<%BANNER%>

Effect of Alcohol Cosolvents on the Aqueous Solubility of Toxaphene

xml version 1.0 encoding UTF-8
REPORT xmlns http:www.fcla.edudlsmddaitss xmlns:xsi http:www.w3.org2001XMLSchema-instance xsi:schemaLocation http:www.fcla.edudlsmddaitssdaitssReport.xsd
INGEST IEID E20101124_AAAADL INGEST_TIME 2010-11-24T23:24:49Z PACKAGE UFE0011373_00001
AGREEMENT_INFO ACCOUNT UF PROJECT UFDC
FILES
FILE SIZE 21848 DFID F20101124_AACOLT ORIGIN DEPOSITOR PATH paan_p_Page_01.jpg GLOBAL false PRESERVATION BIT MESSAGE_DIGEST ALGORITHM MD5
997b0aaa1b2481cf0d93b24c03098a96
SHA-1
5a2119307f3dea3a073199514a40b7029d183403
1355 F20101124_AACOVO paan_p_Page_02thm.jpg
61550e2af42dc33f61cdf1060d5f6333
7fc5674b4e3205d6a5bc266643d495734141dda1
25271604 F20101124_AACOQQ paan_p_Page_39.tif
4b40b4d06163f85626323122cd6ea1a4
34497859ad027352dccae998487fa7b3a335f4f2
10139 F20101124_AACOLU paan_p_Page_02.jpg
b3a3761fca4f01fbbc5cf99bc6ebfa75
50d00fbc8331cf2c1dfc91b4cadb1c6eb8ce0112
1053954 F20101124_AACOQR paan_p_Page_40.tif
e9fe18d2018b5c065cde4c5066c86770
eb5e6c12e9abf2f0515b9d1270bdcf2155a8798c
17953 F20101124_AACOLV paan_p_Page_03.jpg
5180fd564f3342b1043a1590ccb6dd5b
ce55d1299dcfa12856b033d2876e17ac6d0c3305
4530 F20101124_AACOVP paan_p_Page_06.QC.jpg
abd860cde13f8ce29e1b59eee0de47dd
dab97823ee92ec55c9c0fda7995f4e1c23be7f02
F20101124_AACOQS paan_p_Page_41.tif
4026fd103547f25c6488dc6059888c8d
c3ae6f4fb2ce8023ed99b0570c1047de8f5c7027
30151 F20101124_AACOLW paan_p_Page_04.jpg
18714f3e92c6f6663c5fd140b52fdb81
0824737f2934cd408f8afab5ef483705a5c6b899
25277 F20101124_AACOVQ paan_p_Page_16.QC.jpg
8e0da96cd1131b50cbfb376589731a1b
d5a8ef0abb4f384a7beca22655bedd39c6bf5bef
F20101124_AACOQT paan_p_Page_42.tif
267bc98d9c92b53989e8028f2717a3f8
2753f42cb57ec2eb0f306a700b784bf5819c529b
62953 F20101124_AACOLX paan_p_Page_05.jpg
d1cb1cca46002f96a11c2d053a6fe737
69e276d98958f8f0c3d40c60b1ae8b12037110e6
6149 F20101124_AACOVR paan_p_Page_43thm.jpg
fbc197491ebddbcd6349e885ee6570e2
b07a1a820931d13348cafa91871876266355b990
F20101124_AACOQU paan_p_Page_43.tif
91fa5eed586372e8d2b3177fa69a2104
05cd969dd0396f5be3d6520370a57034ff0b3070
15386 F20101124_AACOLY paan_p_Page_06.jpg
379362f115e7c201c84bf7797b590b0a
70b6993c61ce3fa4929b9a44212fb11a09646c11
6803 F20101124_AACOVS paan_p_Page_01.QC.jpg
de9786cc883bde6c4c797d2c029ee310
8eaad985877f765dd4db66cde59d2dcb028bc13c
F20101124_AACOQV paan_p_Page_45.tif
c0c10159212f4701014610826ee2c7e8
ae5e715a22d0cbef343064dc7368766aff93647f
29918 F20101124_AACOLZ paan_p_Page_07.jpg
777c03ac4847dc5141f814c0de446c25
95bf5dd731d27c33ed397da6bb11b70d54e682b3
1701 F20101124_AACOVT paan_p_Page_06thm.jpg
384bc9ca7f39956cc1a17646901231b8
885818cc412c70ddfa6481ed9cac5205d78e8199
F20101124_AACOQW paan_p_Page_46.tif
74688c7cb53eac67a364c63299e36f99
e5f39b5d175b1c2fae6e848128f3168bfd37c4ee
3213 F20101124_AACOVU paan_p_Page_10thm.jpg
3816bf0ff3d510e70c11f98a0fc97024
1516604346251660f7e2989e84eaf9b2c2d93975
F20101124_AACOQX paan_p_Page_47.tif
0c04392737aa91f24186c889ec1b7904
ca9d5034a530104a39df3ccbbf3217d4e4b35163
23438 F20101124_AACOVV paan_p_Page_22.QC.jpg
718324d29aeb37b47cfcd1d1b5dad606
1e73e27328c426162f8f5ec829c08d9728fc6fda
1011296 F20101124_AACOOA paan_p_Page_15.jp2
81779b677311d2a4a9ebf786c441f6c8
ad42c1f24f9f133378d45e95836a290c78aeb95d
7618 F20101124_AACOQY paan_p_Page_01.pro
9fddbd8c8445a0ee7ee8c2423f9568dd
631319d21031420f0899ae879ad80e5d8bf955b4
2726 F20101124_AACOVW paan_p_Page_25thm.jpg
bc2111523282009127593e2770b51176
6aea26a30cb636ab8bcb34d873e7ce9bca113a63
1051957 F20101124_AACOOB paan_p_Page_16.jp2
8f833458b5e90885bc553a14ea8b7f68
ae03a44783512ce6c8423286816cca7465cfdd53
1041 F20101124_AACOQZ paan_p_Page_02.pro
898e3ecf269550fd5079003cf87b0292
d149eab5321e87b336b63d80c200cc3f92d1fd35
6211 F20101124_AACOVX paan_p_Page_13thm.jpg
316d899c51bf6fc2b0bd55ac7a688963
41108e6ff9b208ac438a05a276dcf38fbf0a826b
93327 F20101124_AACOOC paan_p_Page_17.jp2
09d6bded02f9b63485227730f2a038b7
928c2b7be4c7983a58ffcf2c865f3bc7c4e2febc
739 F20101124_AACOTA paan_p_Page_10.txt
61261cb632004926f681e859f897843b
66ac6f157b9670f0b6f486589affd60bf44b6e70
5857 F20101124_AACOVY paan_p_Page_35thm.jpg
6d8424b50e6aa3f28402c6d098cc7a2b
cc5c3ff163fce2c79e81aa43e6fdf8f8acfd1dd4
99096 F20101124_AACOOD paan_p_Page_18.jp2
cbf7d13608a64b3ef9f9ee3b918d27b4
68a6da78efc322d0051a0e5f8b893f6cb47d3f63
959 F20101124_AACOTB paan_p_Page_12.txt
6e13731ce8fc1b441c4146f05b2db745
4691b6716334308ab3b54e1ae407547bd2b6e7c7
13855 F20101124_AACOVZ paan_p_Page_12.QC.jpg
71cf6990b6a73a993ed8ec220b54f383
b993af56a0a0cffa74404a5d723950edc2b64e09
99703 F20101124_AACOOE paan_p_Page_19.jp2
871fae196dfd0e411e55de225fec9859
2bff8623f79ab47eca7af2f3bf91332da71f40bf
1841 F20101124_AACOTC paan_p_Page_13.txt
c3da3afd43d64b9d6173fe64865edc6c
0146beeb16d325efeafffeab7e0e382e8b0d8ca2
1046394 F20101124_AACOOF paan_p_Page_20.jp2
f028c711d986363e0b993cb691e2e1e3
80ea535e519c8c039a303b16ff5163c141d86506
2053 F20101124_AACOTD paan_p_Page_14.txt
a57446522306c899f0ed7deabf093926
5a73d9815a9ab22fe84ae9cd0851eb8743b37e91
106041 F20101124_AACOOG paan_p_Page_21.jp2
8d5f80ef78ae61ff65afecdeae193f42
d48c11293456bea38f74d4ae91bcfc8d310c0f05
1871 F20101124_AACOTE paan_p_Page_15.txt
073510b770194dd1b22c10bb2edbd515
55b701e5c51be841c6e06a9dbbf0eb35fca18821
937427 F20101124_AACOOH paan_p_Page_23.jp2
c5be4ba9e917330907972312054dc6fb
cc11d4b97a27ee78e03f88f5308b2a4af5f01d9c
1986 F20101124_AACOTF paan_p_Page_16.txt
8c7a363fe071dd5276e484e715695f11
cb3c3ac2c1df1a7838936bdec95fae40a96092d9
1858 F20101124_AACOTG paan_p_Page_17.txt
6510d63e82bd17b71356d38e8fb68ca7
f416e254e9647a269a4440af5b5b52282f38e1f5
111620 F20101124_AACOOI paan_p_Page_24.jp2
1a507d4349ce42eb5e16dc3851ebd6d7
71769d185630a01c7a96bcb00ccd4ae1297d3213
1917 F20101124_AACOTH paan_p_Page_18.txt
7da65b6f34a0e5d27f7c8c6dab0855b4
db8d958e5319e4fe121a8be56f38b614bf80df5f
34131 F20101124_AACOOJ paan_p_Page_25.jp2
daf3020b8f068f99b249a80ec3638126
eff5047f45bf4477479aeeb77f10576ef6f18ed7
1909 F20101124_AACOTI paan_p_Page_19.txt
cbdde7485e798a5082046f650259b5a2
04a2dca532fa20cc43fbfba0409c52892039084d
80012 F20101124_AACOOK paan_p_Page_26.jp2
e46ca51ccf102d8de93867e5dc3c1efa
28fe3a311de67c51e6acadf79fb1a9658212a1b1
2019 F20101124_AACOTJ paan_p_Page_21.txt
4ae18fd9540b0599ab39543659a40732
4aefab2bcbec6cffbae4b14d44745d3d2702c5c1
913623 F20101124_AACOOL paan_p_Page_27.jp2
542790c159e8d7090cea71c2da103ac1
54e09bc01150f6095e000bc6381ccb576a2b57fc
1051953 F20101124_AACOOM paan_p_Page_28.jp2
b7006283546a63fe9acc8c4b63bfec59
cd6f55064af3ab7b107983f41e7629807097742a
1829 F20101124_AACOTK paan_p_Page_22.txt
ab223bccf686cbe94662032f787422eb
f98b1c5a294502393ee648c39e157a973035d75d
38302 F20101124_AACOON paan_p_Page_29.jp2
92c041111527b3c64fafd9088f7988bc
f352f8471747f736e780a82d67c050c56d69bec0
1545 F20101124_AACOTL paan_p_Page_23.txt
e8c0642ebd99842ea372edf3817b485e
4cfc474b882b45f24a6b3b6a78603f95ed267115
595090 F20101124_AACOOO paan_p_Page_30.jp2
6eba12875dc63e605c293290c541e5ba
c9e6f12737e7391d5c8ac42de91fd9a0c389d3e3
2028 F20101124_AACOTM paan_p_Page_24.txt
c1f1d8f0d2e347db68ff10d7dd4f5bb1
6fa69e75776e68dca201bd165016dc93506a0270
557039 F20101124_AACOOP paan_p_Page_31.jp2
c2b4a2d57257da53bb4f330ce542f9b2
8a248df3fef1d9994fc1a8e63ff86490649bb7f1
79777 F20101124_AACOOQ paan_p_Page_32.jp2
7139efd9e5cc23591464dd5ce9fec1b3
54c33528901a870f7f7d1dee4be2d7f2cfe0657a
587 F20101124_AACOTN paan_p_Page_25.txt
541a0a08a4a507d6d8b7b4f74303e890
ffd42df4f6c513860495a69ef6bd84069bd8bb4e
715571 F20101124_AACOOR paan_p_Page_33.jp2
bf238042647238d7e40a8c599ffdbf96
99fef76f46eb22efcbe6204dd7b57ec0551cdad4
1505 F20101124_AACOTO paan_p_Page_26.txt
223ca15ae5b28713d986b9084b3e7998
38117d8cdfb34fb365c6495cf568b4d54eedf626
870342 F20101124_AACOOS paan_p_Page_34.jp2
924bb6438b938cc669ca656c3bb51931
1d3172a56cedca73bc8e26f04a3b6a7aa9bacc23
1919 F20101124_AACOTP paan_p_Page_27.txt
6f6a2fccdd0b36e6a2d523f75e72327f
9d9a54c38fc54d2b61f0d1bf551969af058d30a9
84765 F20101124_AACOOT paan_p_Page_35.jp2
bbf22bef5390a0abc827f933c711d486
bb03a9ec1a6513a9854e03ebdf64bb8b18ab901e
1328 F20101124_AACOTQ paan_p_Page_30.txt
d6f7ca172befc6d5b6bd87ef4ae533b4
2d56e06b6ed987efa19aac4d87a23b26817d5999
95915 F20101124_AACOOU paan_p_Page_36.jp2
2af7e7ae7a4ef4583521edb9bbb80f19
fccdf2456942ff3fe6e71e53267e46298c482108
916 F20101124_AACOTR paan_p_Page_31.txt
08a8cd701754423cbcdc9736707b8c0b
f64b350c4ae6ad28881db0e6ba8be471e8bda0e0
96424 F20101124_AACOOV paan_p_Page_37.jp2
e8ac8df1177cd8d69db68335e771868e
d7652ed6c48147eb7e83ae0aa095668f38e86d6e
1453 F20101124_AACOTS paan_p_Page_32.txt
85ee60862860f7008767e5522cb7a331
0203be1a542c6a69e431b17bd7be04d283ca1b94
534174 F20101124_AACOOW paan_p_Page_38.jp2
18630f7afc28875ba2df66643f2ad5ec
28530a21faa05b20c1a491af9166d58de2091a80
1886 F20101124_AACOTT paan_p_Page_33.txt
6a876b61ff2a9198d60d651bbd695858
b3cd2bdd63bfe79c3424ee345348d1dcb4f13a2b
852354 F20101124_AACOOX paan_p_Page_39.jp2
c78b0ae3b78c5a2b0cfe59bfb0fa9c89
60cf92cac62f4688b0f87c7ed3d1985257a2f8cd
1952 F20101124_AACOTU paan_p_Page_35.txt
69d9133cb3e665857e96fbe4d2478f8d
56069b04143e747e6a9d03e92d02325f383485b0
87430 F20101124_AACOOY paan_p_Page_40.jp2
f4e20d575a6963e104452784bce31ce9
54e4e934372b0a7c656cc002e3b6ee80a14dd743
2006 F20101124_AACOTV paan_p_Page_36.txt
dd5f54c2e555cfc0964792c6b3acb784
017b7c42cda54e6db2c7c3fdc7a277ac997340a4
45447 F20101124_AACOMA paan_p_Page_08.jpg
2259ac7adf30524052a10bb95fcf48fc
4fc423435f33fd94482bc52e7ce7fa4ec93d95f6
95440 F20101124_AACOOZ paan_p_Page_41.jp2
64bb989cdabbdb939b733417259e299b
ecbcedceaeeb6bdc75abcfe9e98cf68132d26e30
2022 F20101124_AACOTW paan_p_Page_37.txt
df2701ba5f925f1233451957c4dd8afa
fe7a190b84ef21a608f0539eb678baa921be419d
58862 F20101124_AACOMB paan_p_Page_09.jpg
f984b5c0c448a8b8487890e323037d41
4d48e035a82e305d06faf8013320a197988e6caa
980 F20101124_AACOTX paan_p_Page_38.txt
6cadd5f296d01d7177dbbfe91d41748e
e992d79f97355aa3bf35912b296cd25d3acc2a75
31580 F20101124_AACOMC paan_p_Page_10.jpg
0c44b48fd6ff146243328b8e59a799eb
2832094d6a3d936e11b345e25ff697d7b1287be0
16367 F20101124_AACORA paan_p_Page_04.pro
c40334dbc642f9e4714795653fa3d7df
e15a1ab23f6394480ff540c988772a89514c9d79
1930 F20101124_AACOTY paan_p_Page_39.txt
3eddd96fdcbad5e560c3c076c2cdf9c7
6e9264d2c6b5984ef409e46e06d6c6b15b1be289
63741 F20101124_AACOMD paan_p_Page_11.jpg
429c37440e6343c435c9bd6c5ec0cd30
ba54f436e067d174e45611bedda6d9f1400e1e71
74079 F20101124_AACORB paan_p_Page_05.pro
15a605b95b179262b0adebdfccf3235c
27c29083f40d12c685eaa2deeea4f413fce6d3fc
1635 F20101124_AACOTZ paan_p_Page_40.txt
0f79af8e28cf85d9c9b3fc1b1147b181
1de49995b8cdd8ecfb98bba178c6fec60847a08c
43572 F20101124_AACOME paan_p_Page_12.jpg
ddba22538e3dfefe9515dcc35a36722f
b17e330b26f2b377e22d481b4fdac478a799a387
9851 F20101124_AACORC paan_p_Page_06.pro
17d2552bc80d3c9bfbfb8f1a30d27e20
abeb3f1a44aa4dfedabce33fdcf98d59c3b72aa7
74424 F20101124_AACOMF paan_p_Page_13.jpg
21e3cfbd952c30f886051bf5a9d82c02
66199d0f21174399914e8685ad23e94344f450ab
2903 F20101124_AACOWA paan_p_Page_29thm.jpg
ecd33061caa3f1871cf8b88308a7d484
2f3602ce952fb232b9b0f384da9b6a8882e688f5
19572 F20101124_AACORD paan_p_Page_07.pro
7883d8ef740e934d13de11031c59264d
f61ef8f06fc32cc8268d671e49a808a524eb804b
5148 F20101124_AACOWB paan_p_Page_09thm.jpg
b8c528f2e83f35c75705b470a9f05243
e35accb59966af9aa9f592c7c0951a8b990b186d
33391 F20101124_AACORE paan_p_Page_08.pro
563a0c6101bb6fe1b2e4987782533838
285f8ad0c8f9f87b70af0cdfb077f2ac395c4767
74060 F20101124_AACOMG paan_p_Page_14.jpg
31576254ba6752263282bcdce8d1ba32
963b9c286fc2eb641a651e425b3b265bef83b06c
3053 F20101124_AACOWC paan_p_Page_04thm.jpg
98c2ed97bb791250d5610993c3e196ac
c32451035ba39f061081cf9accdcfe07f4667281
38069 F20101124_AACORF paan_p_Page_09.pro
171106e92e44da8a906bd6e10142dd1e
bacf9897c234541f521dabc9cfca228c315496f7
72266 F20101124_AACOMH paan_p_Page_15.jpg
463c5779a318e6f9ac31fad72571d58e
5941639435e5703fc14adf3a468198ff6d90a81a
6955 F20101124_AACOWD paan_p_Page_28thm.jpg
f8509e1621e9aa3864cd4d0930f13f46
43febab08e6b86006f847d437766ddb7905f6f17
18551 F20101124_AACORG paan_p_Page_10.pro
00a40a934e3a140894bf5f30b7dacfc3
6e6bf6867af4689defaeea13b74a926845e0eea9
79583 F20101124_AACOMI paan_p_Page_16.jpg
2ca434fc511d68bc45b025324afc18df
08093454617f4b5b16c027e228d5d0844d9d1515
8264 F20101124_AACOWE paan_p_Page_47.QC.jpg
84d20d6734d0c3cee18940fab24f868c
ec70b2f7cbe05f3ee0e7f58f160925fd857dad0d
43578 F20101124_AACORH paan_p_Page_11.pro
8fd45fcb4fa640638a04f7d21093a30c
c5944f0e879a78b3497b7946cf25f00b7b5da181
62006 F20101124_AACOMJ paan_p_Page_17.jpg
27e2e50c39359a07b9f9bf9d45a5a420
31bab14c3c23b762b825c35d020d063139094290
4500 F20101124_AACOWF paan_p_Page_05thm.jpg
71ff84c0d6a9cca756c758fca0aac6d4
fa88c55ad71f82b738c1c730481c64015b130f91
23990 F20101124_AACORI paan_p_Page_12.pro
81a0f0985c9a840fc62bd1f0a9e3e81f
fc18bfa3e31bed8ae46bcaa9dbfc6921883c5c5c
66472 F20101124_AACOMK paan_p_Page_18.jpg
2be2011fa886c1e88a98206da8699c34
2f1eb51f94db35e157267b36d1f0a99a0cf02161
44366 F20101124_AACORJ paan_p_Page_13.pro
ecb4764f2679429f1e205f9441fbecba
7d8df9232d760cc5acfbf76e3cc0a2e695df2ced
66047 F20101124_AACOML paan_p_Page_19.jpg
c8f42fc8f5e82399140c7eaedf60fa51
96ed1105eac630fd0b4ffbdd617f43fe58f8c3d7
6212 F20101124_AACOWG paan_p_Page_19thm.jpg
def9dcefcf3c6952976c3d807772e545
0d6d258ecab36c660c936fac1ba2f7f9a2b827f9
52332 F20101124_AACORK paan_p_Page_14.pro
4558586f025a17afe69f2569bbef0ab1
120b7a702285b608c35f80abd8d7efebb4d4c858
75906 F20101124_AACOMM paan_p_Page_20.jpg
381df6de2f16d8bb5e30302d04f3a3f9
a8c0a83e9e77cb8689a1bb9ffd38194abd33575d
24279 F20101124_AACOWH paan_p_Page_14.QC.jpg
c357d174eeb85349d0b9eeae4ca1dcf9
0f683610de9cc67b7f1e77013fd8061ed4d0d4e1
70206 F20101124_AACOMN paan_p_Page_21.jpg
990c803241d7246af86a012b75b0fc22
7d445bd6ab153053145abf7f88437506fcf77870
8963 F20101124_AACOWI paan_p_Page_25.QC.jpg
6d9e4fc7b3db346f818560a71acb0615
d4c75c94208a4f3448e23c5197b5209bfd9be5ad
46091 F20101124_AACORL paan_p_Page_15.pro
0efd42316173458b73c4a2e50f49a198
d71e76336181fd883e362306241453621d0941ca
70728 F20101124_AACOMO paan_p_Page_22.jpg
9b4a944ff82bbb35f5d6f7adeae21a18
8891bc8cac7ab56dcf9fb1914766e88e905739c8
22029 F20101124_AACOWJ paan_p_Page_19.QC.jpg
3d08cd4258d2c9703dbff238bc69b4c5
cdfc0770f8e9c378c14534828fce962378176cae
50525 F20101124_AACORM paan_p_Page_16.pro
5c042339923ddbdd952f36989905db24
9a6425e9c655989a70ad78f9d2400fabdda08cb8
69147 F20101124_AACOMP paan_p_Page_23.jpg
58231186145abed761817614a6787554
0d8dacaf54cf309cc755205a18ecaf0eafbb2b56
13404 F20101124_AACOWK paan_p_Page_08.QC.jpg
b1a3f576fb1622d97fdbb31b3f9b60aa
335d1a4cd344daf81dbd0dc2778d9036b2895f11
43711 F20101124_AACORN paan_p_Page_17.pro
c6b3b03ee44400e64579b038cd2e1088
ebd356d3872ea1ae3a9fc379e8ca56b636cd7490
73301 F20101124_AACOMQ paan_p_Page_24.jpg
f7cccb3a48a11a8d49040d200418906e
989ae7abd268ab123377a0d7fbf2697f005d4539
5309 F20101124_AACOWL paan_p_Page_03.QC.jpg
f100859b890931f412cc686ccad54f89
d597a9c7c83d69b64d5fa1cde948e2426abf058d
46480 F20101124_AACORO paan_p_Page_18.pro
d198c5913e5c886dd5a5042467b556e1
f7394ff4cf2376a6dc18dd1c55b15707922c1932
26662 F20101124_AACOMR paan_p_Page_25.jpg
43b76f2416b616422e8cac91a8705fe2
8d8bb5684c3fa4fc85b02caf413b970db4562a12
2807 F20101124_AACOWM paan_p_Page_46thm.jpg
452033fd10d9c22fd20a55a1b0df9cf0
d1473e06eba8a9b564c6fc212fa1eb3e89a3f6bb
47012 F20101124_AACORP paan_p_Page_19.pro
f5f770cc05b4b29748619fa738d79ad5
99bea010c54297b29fb30ef42f71a05e3a5181ab
54306 F20101124_AACOMS paan_p_Page_26.jpg
43ae49f1e53a066b8322c83ceed6609d
156b297cde4a18fecf7daef135b03ee33982d65f
23363 F20101124_AACOWN paan_p_Page_20.QC.jpg
ae3890c070f18a3e3e0ac1e1d10b551a
aa0837ab206a2b0b5e1b5eeb98cc4c62e2a7e2f1
47117 F20101124_AACORQ paan_p_Page_20.pro
c097cf91a1460dc8638012a38ef9adc1
ba833f5d1ec8f9c24b42e73daf9fc958a38476c6
72110 F20101124_AACOMT paan_p_Page_27.jpg
a861e7609cf9b5f8ea8cc6fe5b2e71ea
a12e53a81bfee56a7406d266a9e6ed7520912193
5927 F20101124_AACOWO paan_p_Page_11thm.jpg
015e2c3a3ae028bca4526639dee21742
c2320348289ae1d74c15c8b2d1c611bcc2a3675d
49716 F20101124_AACORR paan_p_Page_21.pro
f8cfe27bf8a174c515b13dd5675d129a
9c65acbab3300a374e5504798eb20b81549837b7
78740 F20101124_AACOMU paan_p_Page_28.jpg
6ccdcb0c7a4f473c3e83d80058dc2d8a
d012325304e399b3d7644845f1fa38b76cbf9f32
24844 F20101124_AACOWP paan_p_Page_44.QC.jpg
737d84755548c8ef8cf228e44f2f77b4
173e3f68a8f927ced51eef4e1af3048cd944f0cc
41284 F20101124_AACORS paan_p_Page_22.pro
726c63800e88bd084a05499ab294fed5
6b00692b46fb6db131ea4695f83ac87ad71c1979
28188 F20101124_AACOMV paan_p_Page_29.jpg
b70b59eb3b5b31fa76485079b6f21b1e
7ecbbf8c3beb19f5bcd124a1f491bbb64d281824
38231 F20101124_AACORT paan_p_Page_23.pro
cd091e0a069b58384b3815b775feaab5
c0ca26dc1345db1a1026a933671c684b49e832ae
45838 F20101124_AACOMW paan_p_Page_30.jpg
a0c4c596d9f17ebc54510b817e1d0f0a
01e600accce8997a9b6d02a5bec9543fc869447c
23657 F20101124_AACOWQ paan_p_Page_15.QC.jpg
f9291ed9634a2e280d740decb0186e0b
9e2b0a2ff3d0fb3b47bece797a44b44017f11478
51465 F20101124_AACORU paan_p_Page_24.pro
7fd4522082b1fcc70fadc117790f597d
0349489fcd2e3386df5b09ba670983ce541c2e6e
42581 F20101124_AACOMX paan_p_Page_31.jpg
237598d8377fa32b11587675934e4441
adbe3d3cfbf3fa1bc2035e4994fa2bd2dd167e9f
19769 F20101124_AACOWR paan_p_Page_35.QC.jpg
708b689a7f781dc44320fafc00072462
9ec7348e0477fd5567423075587e968badb438d8
13745 F20101124_AACORV paan_p_Page_25.pro
9aa34427358beebf39d21554730ff332
f03015b0f82d21f852f4f3e01d651d950f94246b
53840 F20101124_AACOMY paan_p_Page_32.jpg
2dfec0ad05366dac2b8e8246f4be0648
72f1925f0fb1ee263ec623af5fb7d0e58002e1a1
22836 F20101124_AACOWS paan_p_Page_13.QC.jpg
ada3a20f471793c77f78d737f308c013
08d62d913fc8109c0deba614e3e95229de94d974
34911 F20101124_AACORW paan_p_Page_26.pro
20807b612b31078553eb21d4eb533c65
eb41b0acb8f125670912015e2fc4a349254fca6f
55355 F20101124_AACOMZ paan_p_Page_33.jpg
6e894d6ddfbeebf9d73daf7210e5b2f6
a9d262c7ff4e026764a8bae52b6948083454a3d9
9472 F20101124_AACOWT paan_p_Page_29.QC.jpg
ef6f233b2260147a8bb8721b65e45d4b
c73d66be054e7f4f57d43cea1d64d9fee1948e9d
40736 F20101124_AACORX paan_p_Page_27.pro
55f71345247dcba0389d5cb0181ae12b
33d76e2cacc12cc4b968908ac937778612e3fa88
22426 F20101124_AACOWU paan_p_Page_36.QC.jpg
bed96c21224dbcd7498e9e554b13e1e3
40598915af3df8d28a6530dbdc25c45157d46566
49343 F20101124_AACORY paan_p_Page_28.pro
6aa4a89f7e8d419b8c9dd1369f57c67f
11be0cb7b5702c8bf972f03d5ec3623b0140f69b
6605 F20101124_AACOWV paan_p_Page_21thm.jpg
b2acfb333bb9563baba156b74283198e
a62bc18b858f6d76738dc6fbc35516e3f7bb9f87
232407 F20101124_AACOPA paan_p_Page_42.jp2
a7a89de222b75526bbc739a8c9beb112
ad080348e14d39c5bdcac1bf8c6f8996731baed0
15565 F20101124_AACORZ paan_p_Page_29.pro
2d12fa8c785d941ce524641fe7640836
e64149bbed2719a23fa0eefbf40c6557ee54931c
F20101124_AACOWW paan_p_Page_02.QC.jpg
c89594953a1019cae76a25cad810f23c
329bfe84f00f47a440d9f201f1a7685100117fc1
113477 F20101124_AACOPB paan_p_Page_43.jp2
80ca390229317b46f0410e43b635be05
3ac479a7cf790261c9676d1a85870177389ce4e9
6393 F20101124_AACOWX paan_p_Page_15thm.jpg
621d28539f37884327d57bb11cb85a98
bc2ea62d47c90dc71e6e4e56f42e550715dde13e
122127 F20101124_AACOPC paan_p_Page_44.jp2
e638ab74e3996119bb81d910a0a365eb
f8a9e6e0b5765607be029816a0249e1203f4199f
459 F20101124_AACOUA paan_p_Page_42.txt
66d62961edfcd89f188d656f65b91d62
2cc7cbdff595695528fdf6bb719acd0810063f24
1875 F20101124_AACOWY paan_p_Page_03thm.jpg
28837d075993e8f743a9a6d9a2b6dde0
d562c67b975cf55f143a855c8d39c1ac1a5f44d4
119947 F20101124_AACOPD paan_p_Page_45.jp2
2bf1ba2bd706905052e7563bca54bf5a
8eb9de3c385743764385b541a6e145fe1162fe7b
2306 F20101124_AACOUB paan_p_Page_44.txt
4d2bb033e9a15437031f7875e8ed6afb
b1e0d0a10e3b6d169c166c458cfc3ef6f2f90479
4620 F20101124_AACOWZ paan_p_Page_38thm.jpg
6e6b5a3878240ba939a0e1f2346e0414
2f2ee2b24e5c67600b20c13136a6a19a93b49263
39538 F20101124_AACOPE paan_p_Page_46.jp2
7e3ad14c5548c136dd4f4602df42d487
e721eaf671b3910e2af1ae5f659c241e6c5ef2d1
2248 F20101124_AACOUC paan_p_Page_45.txt
23aa480b508057bfb1f190a9e7b90605
4f62a7d0d107bfb98dd1e5ad9c56be5b0e6a3c04
29525 F20101124_AACOPF paan_p_Page_47.jp2
9c1a51d63ef742d2ca633a9a0ea385c3
deeedf2aa5dce66a31d47a4523d58af84996f69d
703 F20101124_AACOUD paan_p_Page_46.txt
b6db74e0224b7c74a2f8100a8223c484
453cbb6cc7a48f96b2a9cc01abed8299023577b7
F20101124_AACOPG paan_p_Page_01.tif
55ed570c1338f3fdea7032aef2f8b30d
526b396e7718da08145c4bd56db3f42186eb417c
520 F20101124_AACOUE paan_p_Page_47.txt
a3838bc794943f059a6f8aaeb3e7ece4
514461f89a5f90e2f6e0b2f5a8a263d316157ee4
F20101124_AACOPH paan_p_Page_02.tif
b119067dc41d18975bcf9064b42f87a0
13b97a60a53912f16806ecadecc183f810c429c1
326649 F20101124_AACOUF paan_p.pdf
be6d1d0f015887518175ae2cbd7703a9
f347bce801b67c8f75b9ac76e1d3fab0dbaea662
F20101124_AACOPI paan_p_Page_03.tif
15b2552d601d1966b02e9e54a2217968
27179b763f367df1af042add9ed395b84ab88e3c
5247 F20101124_AACOUG paan_p_Page_33thm.jpg
f0b34912193668b55a7cacbc1cc84e90
a5b92801df050e9fcbbd92968c6dbf9770261517
10298 F20101124_AACOUH paan_p_Page_10.QC.jpg
e0e657eb3598e43dc7eae1f1b9638360
fb72f24ab5876f81b57ed4ab68af202b461a9117
F20101124_AACOPJ paan_p_Page_04.tif
91558a82e9bbd4ae7fbf360c39dd7b38
3b86842d078ffbc91eb8cae49897c8224bd58f99
14735 F20101124_AACOUI paan_p_Page_30.QC.jpg
03059e21ece5ee4fffaf79ccd19ea6b0
ec464de77bdae76b8f83b725a378ecb71a2cef39
F20101124_AACOPK paan_p_Page_05.tif
78bb14736be2d544bfb731468a6dd90e
4eb2bbbb26a110413e40f0ee2101325512e25563
4731 F20101124_AACOUJ paan_p_Page_31thm.jpg
ce92facac8772b93747ba11a9ebace15
39ebcb17b142a66a499bba92a155e3e5d6937a1b
F20101124_AACOPL paan_p_Page_06.tif
9e93383adc08bff125f72d75bfbc9947
ca6b455007e0fafea552b5f6c48dfad6cc89ea42
6622 F20101124_AACOUK paan_p_Page_24thm.jpg
cb8c230a297c5695bf973e9cf23a7a11
dde21b378daf01e58ba1294b1216baaffe9ad8e8
F20101124_AACOPM paan_p_Page_07.tif
4a5fa9edae5c7d8a1f6ed7051b8e1b15
59fefbf8083837160b495d53b3f7e88130e24c2e
6396 F20101124_AACOUL paan_p_Page_45thm.jpg
c46dc2231f9b605d71298f71576f15d5
22cc34273ab4c6d344f93fc0c21a53a9d992cb9a
F20101124_AACOPN paan_p_Page_08.tif
4ce3ed9e39e5f14b0d55434dbf1e9a4d
4fe88b35f132f95a57a726a129454644aa986a27
6436 F20101124_AACOUM paan_p_Page_44thm.jpg
0b212450ce8d12147202e1ffd30f49a8
f369552e399780838314a442424895fa3211f28b
F20101124_AACOPO paan_p_Page_09.tif
229d8e491672c9428b0250dcf970ca64
b3f9412783db8f94aac59f23644446e11a237227
6251 F20101124_AACOUN paan_p_Page_37thm.jpg
dd2834dfeaad6165cbc7ade66b19e4ce
1f999ff02185160a25968213c21fe16f3d0e11eb
F20101124_AACOPP paan_p_Page_11.tif
ea15e1182b230e9df31fa01f1a0f56e8
266979e13eedcc89fbdaeb05d6597e0d90ec2058
F20101124_AACOPQ paan_p_Page_12.tif
7dd40c4ade3f96f51d0c612d212d961b
8fca0356eccd77a97e722553af7d55db36b642ff
2801 F20101124_AACOUO paan_p_Page_07thm.jpg
af44f97618879d7b4494840166b9e865
38df4f83004a02ee630f96d3e6deed4b54c6255d
F20101124_AACOPR paan_p_Page_13.tif
6e279a20340721ba8eb83a3d48ebbd51
1c98bc18631858f96cb181a0a35eae72392c74cf
9069 F20101124_AACOUP paan_p_Page_07.QC.jpg
ab41aa1ddc4dc52074979b2d8dbdd646
ffd5135c27e4fd64e35650eee1f5e2f4fb42666f
F20101124_AACOPS paan_p_Page_14.tif
9ed91af66fe2781e5fb69602fde90f9e
91a00c70269af9c2158ce1e9cfad145dc63244b3
6193 F20101124_AACOUQ paan_p_Page_36thm.jpg
1037c1986e1e0674692266f027ef6d18
ddeaf529c96785b7a1b6269ea91e3c64ebe5cf72
F20101124_AACOPT paan_p_Page_15.tif
4ab62c8bee5071f1446c2c71983190e7
b39938cf398f00a60e23642b05496c07141ec4a0
6534 F20101124_AACOUR paan_p_Page_14thm.jpg
a2f1f11e771e9e0ddec5378f5741cd6a
2019e9d8fc0d6a3b481e995c0e3ce222c687855c
F20101124_AACOPU paan_p_Page_16.tif
8fd8116f8d4c97c96376a7f2347dd756
3ba04960c0a24bd76cc58535dddea94074e0422f
1791 F20101124_AACOKX paan_p_Page_11.txt
f668cf663e51263e2ea13a5b4a07627d
760b8108166a0e5cd814a4e63efa869d345ae975
22246 F20101124_AACOUS paan_p_Page_27.QC.jpg
3f920a477826b17fb81b25bb75962a88
3c228ef466e3def66b5c3473d4413534552dc0be
F20101124_AACOPV paan_p_Page_17.tif
0c82d6f03f99b279020eb397c289df29
c1c00984533d98a1e3456a210f6fa6e3970a2879
1904 F20101124_AACOKY paan_p_Page_20.txt
58cd1d165bbb17367618ece6717875ed
201a850f007190b839e631909552f6b007c48d4c
20641 F20101124_AACOUT paan_p_Page_11.QC.jpg
2850aacb4be97182a0f2f4983b0c4e5e
99343ed370c781315e2f0f2e1d5eb9b5a4525716
F20101124_AACOPW paan_p_Page_18.tif
40a322743e845dc2da44c28a0eb15d33
9c2cf05c53539ab933ff36b2f746f0a51c1bec4a
F20101124_AACOKZ paan_p_Page_44.tif
27b4bfcc2fe5400141a3af9eb01b6d64
4fe9f3f70445f2df611a5440fb9911a55ddbcaf8
22814 F20101124_AACOUU paan_p_Page_43.QC.jpg
9633145f38817ae4d840e79fbdeba665
99818bde676a3af65704e5bef077a52d877485df
F20101124_AACOPX paan_p_Page_19.tif
054ba400277c39f5ab9a515a5dd152e6
4cd1a0476849bd47e1a5c238653e5ca2cde436dc
5898 F20101124_AACOUV paan_p_Page_34thm.jpg
ae67de93ed3c22f77cb474a3b7994882
feedb271c75d45a0b682de9c1dbd57442cf239a1
64026 F20101124_AACONA paan_p_Page_34.jpg
a4aeced73d9b3626a3b40fe6a7e143e8
6ce85bbe53cc4fe5f8d5cb11eecd74fbe914ca78
F20101124_AACOPY paan_p_Page_20.tif
863210f8ba687c34cbb2c272bd4901b5
70bd42a4418b092d91705b3f1c03b13464c94a89
6174 F20101124_AACOUW paan_p_Page_18thm.jpg
30f3c8cff63a6e8d17d4e109078e285d
451fcf133ce8695720f2b13466f07a104b03862c
60392 F20101124_AACONB paan_p_Page_35.jpg
3c4b94324c61418c03d0d603ed19736d
305dc117a78a4bde029d0c04c46bd6a7571ce1c4
F20101124_AACOPZ paan_p_Page_21.tif
ad4108957b02fb0b080f4018bb041b6e
19ba208060e6662e26eb1b1c9defe6223814093e
20738 F20101124_AACOUX paan_p_Page_34.QC.jpg
77fac9b7aff1f267fadec4c48ec3f3a9
2ab8ed52837f3924880ce246e68e578bdb5e6cd9
67242 F20101124_AACONC paan_p_Page_36.jpg
e4ed19d6860e9bc089306fe30d46616c
2226f1352de9f5b0a9dae2238eac68becc989325
17879 F20101124_AACOUY paan_p_Page_26.QC.jpg
06a7a84c8dd03814e9df9ac0f3fe7fab
beb894c9866db7505ca5ba1391c8f4372198a2d2
71959 F20101124_AACOND paan_p_Page_37.jpg
a93765f190fb5df4edf18c90d65b2152
c2aaae1dde28c0a2054c152bb53db9e08739747e
23292 F20101124_AACOSA paan_p_Page_30.pro
64360dca6718b207b60ed9d05e663ad0
e705ee3af331140791bfe1d3c6afc43f4725c253
5663 F20101124_AACOUZ paan_p_Page_40thm.jpg
04bd968621f4f81ede7071413330fcb9
5c98de2266d50c98b89ba587e5449afdd9f973f3
46049 F20101124_AACONE paan_p_Page_38.jpg
e17f0178590731bb1d8e049a80e36a2e
079f0f62430832020572e2618142959cac9100a8
19287 F20101124_AACOSB paan_p_Page_31.pro
04749bc52ed26f2fd4edfbf7eb9bccef
6f4781cacf576f0a0d1a35c954870ad08024fd8f
62299 F20101124_AACONF paan_p_Page_39.jpg
fb24fa2f3fa2a605540ca9962f875c3e
47591191f1e71c4549a5ca2926cc38394be56586
36456 F20101124_AACOSC paan_p_Page_32.pro
251c8698f3d1e26d9b99c0225684f339
2b99e33ac4d314ab49563d2ed6bd6e4b08a3046d
57480 F20101124_AACONG paan_p_Page_40.jpg
7b28df558dd7e5756fbdd69f86e0b55d
bd35ce6244917a7ac76a961438e4f791c8ceb1a9
2299 F20101124_AACOXA paan_p_Page_42thm.jpg
26f3dd67174c1326e869905dc084645a
1afbf15d70f9b437d3d1634a01e3e4ab592d1f12
32625 F20101124_AACOSD paan_p_Page_33.pro
341598972fd8cbd251153952800b29fb
44cbced74ba98ded52c715bc59fddd1a0adb12f9
9291 F20101124_AACOXB paan_p_Page_46.QC.jpg
1969a91dc186ad93a5032bd2419b9918
e0bcbf9c81d980199e06b6c5f64b68a8c79fce87
37983 F20101124_AACOSE paan_p_Page_34.pro
7d146075bb7ac873053168afaf910a85
6ecccf2b838c1efae1289c58accb345d618a5e29
63887 F20101124_AACONH paan_p_Page_41.jpg
5dacc948af1ad28582df3cfc2578f4e6
c234d4445eeea2eec8dce3b492a2193806813dbd
18395 F20101124_AACOXC paan_p_Page_33.QC.jpg
2c570e784e9ba10dbc9fb6847b02aa93
a07bb99a6972913c519bd8323ba6c2dc5c10101c
40724 F20101124_AACOSF paan_p_Page_35.pro
0c14c0e332d833fa86426c4c041bcbc7
6208f81a307395fba36d8d0f64df686fd9f48c06
21822 F20101124_AACONI paan_p_Page_42.jpg
051a6d81b43152eb4951ab7989853c14
b576bf3f8e6ff9384dea56eb305b221bfbd54981
5902 F20101124_AACOXD paan_p_Page_17thm.jpg
c37f3d888816966bf4371b81120f0497
ed330c3747e180316229d0c3820b18dae714788f
45231 F20101124_AACOSG paan_p_Page_36.pro
d3410ad12aed607bd8f0ba36d58af4e9
fa0cefa30bf6821c732c6fb1f33343febd36975f
87090 F20101124_AACONJ paan_p_Page_44.jpg
c23de53569083f26f0acaaba134bb5c1
557f3e91e0542dd6e09bcbaa17ecd261972e9eef
23248 F20101124_AACOXE paan_p_Page_21.QC.jpg
4cbb44dde83f237e10dc42619c446a7d
212d73b3559ae9d8705f483e603fb30569c3f904
45887 F20101124_AACOSH paan_p_Page_37.pro
fa711fa5c8c0ded5b2649aaea2c1de58
0b47325e1465c29646310606b15cbfc452fc2f56
86374 F20101124_AACONK paan_p_Page_45.jpg
ab43a1ff7df07f97f78495b2b54e1b3b
19ab372313776641dcd9ae1290d559a4f15c881a
5406 F20101124_AACOXF paan_p_Page_39thm.jpg
6411edc1622dcfb31630355fe3ee83d7
588cf9b47e2bc817e2adb1e86f69c5eb721b995d
19123 F20101124_AACOSI paan_p_Page_38.pro
094fab9b5ce877ada1613de8f714cdc2
7fad461f64db58e6669be047f815653ebc027cbc
32231 F20101124_AACONL paan_p_Page_46.jpg
b4a949d49dcef7ac71393ac483fa5672
81a9d80cdc1f89d76e16a759da31d9f252b6a13e
20898 F20101124_AACOXG paan_p_Page_41.QC.jpg
ee697e2570714976c7b148a5f34663ef
125394ad622412f48071af2b5ccc288be5ce1a1c
40027 F20101124_AACOSJ paan_p_Page_39.pro
96e354b4a58c9b16764973c1eb7c5f2b
c1987b252fb2cf3ee032cb02f76880e57ef47d15
24824 F20101124_AACONM paan_p_Page_47.jpg
632e0c55aa47bc3159c158edd21bb7d5
4111a191f139829bf7ebfd053c44f8bf229f1ad6
23617 F20101124_AACOXH paan_p_Page_24.QC.jpg
7b608c5a56d79bc49e7cf6878500ff13
665357b14ce83bf3152da55956feed9f1c6c06c7
39847 F20101124_AACOSK paan_p_Page_40.pro
2758d6c63b696a032fb5571f6d84794e
688c3d1b4d721954ebfab3e5b4ada65a58a9d58c
22519 F20101124_AACONN paan_p_Page_01.jp2
7b4f8d7eb6551dfb55b6b7f253c6ee05
61d3c7388a946223529a7d7bc1577a77fc803186
16525 F20101124_AACOXI paan_p_Page_05.QC.jpg
51b0f930c9e51b2f0d8ee520e0f4ba4f
cc5c9233aa0c48f68d73d29155ef2ddb55813a38
44073 F20101124_AACOSL paan_p_Page_41.pro
dd90c8e57d202af66b2179d65821e11f
bd918c15ba370e0c1edf1f60cd3cd968b9095b82
5362 F20101124_AACONO paan_p_Page_02.jp2
9afb3578989e10684cbad62eb795a34b
1c5db292b377753d37377c7a594225f7df95280b
72683 F20101124_AACOXJ UFE0011373_00001.xml FULL
e89d1d4b5cb836def44db9c118f0893f
0e042cfdd2a720eb42ca6dbd634d998723bbc793
18167 F20101124_AACONP paan_p_Page_03.jp2
a326fde125479afb00d4e3fc7f3cddfa
c7a0af8384f444cf09c07070ad820b2d22f10130
2309 F20101124_AACOXK paan_p_Page_01thm.jpg
8aa01f33c16ce7664f052c2a74de05ae
a95fca377b68f86e5069ddb21206e5097ede428f
10246 F20101124_AACOSM paan_p_Page_42.pro
2f4219059c94e6c9f80e273d8cebc34b
646b1579513c4b74c32cc0b6bb8a12c8a6faca9f
39381 F20101124_AACONQ paan_p_Page_04.jp2
41da3473b9a78582a5d659ecd8a8393d
e039745994a5774ae30d56460389ad60cc63460c
9900 F20101124_AACOXL paan_p_Page_04.QC.jpg
ae5de9d498f97b73afde2b2889a4fb7f
1f694b50bdeec616b48ae2c6c4909d9c6674bcda
51971 F20101124_AACOSN paan_p_Page_43.pro
3112e99c83a4a274fc1a6a409155d6e0
cf9c8b824608485d3da78af2e84992c0784e6f09
18744 F20101124_AACOXM paan_p_Page_09.QC.jpg
47b4e3afc3d301cd2aa622e16591bc65
7068d9adc3cc89b858d1086d33644df9b2810f6e
56732 F20101124_AACOSO paan_p_Page_44.pro
dc936b6a3cab11f078c31b100c7692b8
026be3c8823aceca7741aa85bbaef9cbe1ff4546
1051985 F20101124_AACONR paan_p_Page_05.jp2
ba86ed643f9025ea050dfc566d53858d
2456332aed2bcb37ae8a024ff031f1de64ef23f8
4621 F20101124_AACOXN paan_p_Page_30thm.jpg
e5b79d6e10ad78b281c3b4bfc6d19c9c
a79eb3afdea407f4eabf53147cc77941bab3b7ec
55206 F20101124_AACOSP paan_p_Page_45.pro
d5c0c94da8a179f1fa487f3e199a15b8
8fcb90dbce3bd245f8226ebd9802da74441ec483
219163 F20101124_AACONS paan_p_Page_06.jp2
fb623446fb168e9cf188f1eb4623bc69
d86c5c4c8a4f024ce67cdaa6b55c2b3c1c584019
18147 F20101124_AACOXO paan_p_Page_32.QC.jpg
b5e15101a3adb5457fe5d5156de1b06f
cedfbc557b11dec6102ef09b2b62be7e9d7776c3
16298 F20101124_AACOSQ paan_p_Page_46.pro
f778bb145cedd9b1d16b2d379928e941
1afe58212e877d6433a3064bccc720619017f071
658867 F20101124_AACONT paan_p_Page_07.jp2
c8f55d35a4539a521faf601194e63b6c
0db80215015e3b7ef79ae968981efae76d44bcab
5044 F20101124_AACOXP paan_p_Page_32thm.jpg
a173d42cb00004e58d278cc10572e514
db78dfaa3057da5bd33a8f151027b834adefe24b
11839 F20101124_AACOSR paan_p_Page_47.pro
751d3c8fa7120024e5a0d9b8afe9abb0
949737334a1e5526ce8ceeec343714cc9cd5ef32
84293 F20101124_AACONU paan_p_Page_09.jp2
44e19d687e12403ae6c96fbd8d7bc166
296917623cfac5e7ecc0b1bea43709cdb6a33049
23165 F20101124_AACOXQ paan_p_Page_37.QC.jpg
fe9b3c7b247b2e81046329514d2b4637
c362576679578a0100aace3bb73098ec3e24d3bc
429 F20101124_AACOSS paan_p_Page_01.txt
2275415a1d8ecd588752885918e48ae1
44febdb0ba0739f5a7c9d9e397c892d5755ef3c4
43505 F20101124_AACONV paan_p_Page_10.jp2
0887af3596bc635e76f7e15a49876331
9faa9cb3c7cac71ca5d9dfbbf8f68f3c84624f3d
105 F20101124_AACOST paan_p_Page_02.txt
a685d608a27c64bac9bc67b0abb3c50c
57c9b18efa7a8cba30cb19f8e58d767528d27d60
93919 F20101124_AACONW paan_p_Page_11.jp2
816175bfa5f48af542df1888192a241e
c87ef5a2a97d03d77aa588635683866954ead1f1
14725 F20101124_AACOXR paan_p_Page_38.QC.jpg
5eba6cb2a226b43c5e5c638bbb62fa25
f9a06c2bb5133bdf8156727b3e31854c82e5eeb3
388 F20101124_AACOSU paan_p_Page_03.txt
598db0be18cb33158d324a79cb3e5e89
05cee6db66b7747651682b81656565fd7e5ff220
550063 F20101124_AACONX paan_p_Page_12.jp2
12f750f9462ec604649e9e1fb41be969
c66d2e3547be584f3b111d8c4ed54c3773ef8714
2661 F20101124_AACOXS paan_p_Page_47thm.jpg
7a6c2dc225a5bb2328a7b3067f8598b5
c624504d8fbedbd8f490f4011f7991b53dd061a2
3117 F20101124_AACOSV paan_p_Page_05.txt
f8c964373e4d4dffe48dde7ff0d5dbb7
6ae78839395e44ad307253f17aca19a4e8752f91
76485 F20101124_AACOLA paan_p_Page_43.jpg
d1040771715f6eaca07b43dd796fb2d1
50ecc484caf1a4a985b79550a0582d4a04383e9c
1003719 F20101124_AACONY paan_p_Page_13.jp2
65251fb9e6069e77162cbc7895cd41e5
345b65042f26caaf7f57cfbdbdda3f97a2f41634
391 F20101124_AACOSW paan_p_Page_06.txt
ff860a9921941006b4877475509cc143
dee2ad76aba9e5ef776746de682164a83dcfa769
F20101124_AACOLB paan_p_Page_08.jp2
836cd85c6b8d38b1e595f4644a8e8821
088d413eaa924b38f5ec5c09c9e01a2b1f13a83c
112046 F20101124_AACONZ paan_p_Page_14.jp2
88a06cd6e8974f7f7d1f90b06f1fd6a5
c5b103e6eaf5b10d316d2c6fb2c0cdb002f2dc35
824 F20101124_AACOSX paan_p_Page_07.txt
73a021140ea17456010fee7a933630bd
13c8f6556379b8c7f4fa9b78c392b3a76ad0be6d
F20101124_AACOLC paan_p_Page_10.tif
d10c9a9a5bf2100b9737fbef0eb734f7
8d209e0299375e7e7abaedb48610969c3074ecde
F20101124_AACOQA paan_p_Page_22.tif
bf569c201c37ab27dfd1c584681d83ef
76fe207756fe4fab89b4b0e2029889b3bfad6699
1390 F20101124_AACOSY paan_p_Page_08.txt
fea96117d5ad3249e0bc67594ce5d858
46e15e96f238c775ebd9f5d6f1eed84456b255fb
20211 F20101124_AACOLD paan_p_Page_17.QC.jpg
2ec706554ab38a4f7cd69c08c2ed7e4e
ef44b410165d445ca2998b3554b67e16bfcba7c5
F20101124_AACOQB paan_p_Page_23.tif
de73953497687b8c9e07a796ea204e05
af6e862948e11fc8d6290ce8e0c128019b0e937b
1703 F20101124_AACOSZ paan_p_Page_09.txt
6d15cccab5a76a080d58194ec31ef772
a43bce6216bb3384a7a6259bd846b2cae8c0c5f0
F20101124_AACOLE paan_p_Page_22thm.jpg
4da90ac5c9738b2e993eb0e227079ff3
6df77fe4f89c341f9e7ad464400281f279a1c991
F20101124_AACOQC paan_p_Page_24.tif
153ec7c1231ebfbd711b5579f0c1fe53
3971773dba9844c2a469cc257f0b35e72de559e6
F20101124_AACOQD paan_p_Page_25.tif
31e2be05370e711cb773b3ad6de6a15f
fbbb1a46f676959be6538159db676ef06feb291d
F20101124_AACOLF paan_p_Page_27.tif
96cd6d337e0760efcec01ece83fed280
b8c8033ca423f0b4b4b722cc517f050f39a63772
6887 F20101124_AACOVA paan_p_Page_20thm.jpg
0e060e4fbc343b5886fe14655bdafc7f
c454a9e0f00a03abc52dae65a5655daff38ae567
F20101124_AACOQE paan_p_Page_26.tif
0b3fa936f674e22a031bf0de79d87a16
1eaa6eac1fdce749fa49590eee6da2bb77bc8873
1968 F20101124_AACOLG paan_p_Page_28.txt
ed2b2fffa3a00f9e0da980387a298633
7556d8c0fd34684ca280b1019a97c0cf1280fb20
5179 F20101124_AACOVB paan_p_Page_26thm.jpg
cd27c3b960750fde27ddfa22c239b722
ffa3573920aa1947b7badb6401234ee4929157d8
F20101124_AACOQF paan_p_Page_28.tif
5a5d73e09fe9f05d830aa094f41686c6
4e973651df093f182c6fa754faf199d1b3de71e5
13915 F20101124_AACOLH paan_p_Page_31.QC.jpg
37d6034128d4cebce4cd23c05ba9fd4f
115d13203aab0cf03a313f15d2ddcddba34fb645
6004 F20101124_AACOVC paan_p_Page_41thm.jpg
94693a12a1058b4c8c88a25454fc4591
a888fe85115858f9deafde2039247a5465fa7ac0
F20101124_AACOQG paan_p_Page_29.tif
f75b8bde3388d4fec52e77c67d70cbdc
eee9fe3b233f1cc023ca331f4b339c050fa59ea0
92594 F20101124_AACOLI paan_p_Page_22.jp2
0ed4cd838c38c882369bfe5d75384f05
0ef5ff6935381fe5ba2955d5c6af9f669f710802
19477 F20101124_AACOVD paan_p_Page_40.QC.jpg
acd2204c4dd8ae938525de97ac074fef
273360840c0baa8ab845ac6d8f414b91f710ab3f
F20101124_AACOQH paan_p_Page_30.tif
9287b73cc556ab3eb590058a4e6f97b2
49f3a903a34e7706e96344602bfe9c489c2ff104
1705 F20101124_AACOLJ paan_p_Page_34.txt
b3dd772c675a7285c8b081b120e85676
1cf4ef69df780466bc5163e32ab6943b4c7ca53f
6950 F20101124_AACOVE paan_p_Page_16thm.jpg
49b424b3f0630e90299d54a7b43f0d77
6eec2f6518766c1079a10da3f7e5c234d74dd357
F20101124_AACOQI paan_p_Page_31.tif
2cd084b9f2a8b74e0ad23258436ca2cb
85cebfb423e494a3326db6695049b8662dcc2781
2115 F20101124_AACOLK paan_p_Page_43.txt
3d548cf075daabe7f2361e98fb7db436
c603397d79faec80d4fd4593c6c98080784aa21b
19611 F20101124_AACOVF paan_p_Page_39.QC.jpg
5f6d95101b3c7a7546ed92908cc67534
317c7d29697d6d1baaa499e5c2edcb31b3a939c0
F20101124_AACOQJ paan_p_Page_32.tif
812a8e62e9b135709638d19c56e86677
c1cc40358e6c8a84bf667e3e7edb816a1cf26ec2
3959 F20101124_AACOLL paan_p_Page_12thm.jpg
78ec103785bac6753b3dc1fb10f2e7e1
3a7870993011b2c847518ad0cc62bc359303b2ff
6040 F20101124_AACOVG paan_p_Page_27thm.jpg
899adb15c787a0dee714f91ce5ea758f
0740aa925e52f9891e565b62d5fb461946678d01
7712 F20101124_AACOLM paan_p_Page_03.pro
2dc160a487a548d4d7119dc0ff0d5afd
80f4567ba561db7c046a7e2298333d2c641bae23
6839 F20101124_AACOVH paan_p_Page_42.QC.jpg
71f34b560bf5f6420539695a26bedb0f
20bb430beddc9ac633e5fecb929ac657120955ad
F20101124_AACOQK paan_p_Page_33.tif
c018236b475fc0146aa541639204ab99
da2e80de842e20413635ddedfc235b7eb23817ee
665 F20101124_AACOLN paan_p_Page_29.txt
7010c40f3bb53cbe6ab32f7330128852
f6e63b6dc1bea0ba73f6f634ee8e28dd1e6692c7
6139 F20101124_AACOVI paan_p_Page_23thm.jpg
57bf9751c5c58dd6a1fab3b0ad6ec19c
5102c4a04e667d2a22ac2906ffc40a5d20371392
F20101124_AACOQL paan_p_Page_34.tif
c06072eef3c0ff4531625063037b47eb
b2594a8bc519d9b6c1e77e9be749482c7c4a4eb8
1820 F20101124_AACOLO paan_p_Page_41.txt
d9edda3d9e821ae7c707df2bca8ea4ef
8bc08cc8acbba354af4ade5a9f4a85146e899303
21611 F20101124_AACOVJ paan_p_Page_23.QC.jpg
01be5d8099a0c9ebd483700a03c73179
4e57ac15983c345a74263ffe66d94b1091522592
F20101124_AACOQM paan_p_Page_35.tif
c5b13f9f8fcf6e426faa03663656c74d
d905b863f2b987b551ad6a10c0bbb4375eb8e70f
705 F20101124_AACOLP paan_p_Page_04.txt
29b0ddeb51629d299c4927058e12afef
b6d0ac170a10cf2d8894339c6736caf66a890fae
24821 F20101124_AACOVK paan_p_Page_28.QC.jpg
375312e08893ff2726f13143d163b931
ca4b38562811305af8e6c439e727b054f8ce1538
56433 F20101124_AACOLQ UFE0011373_00001.mets
c437a6d9928776ac788d3d9dbc11535a
89ca5461e1bb594cb31d2b06bed8330422a14e65
4022 F20101124_AACOVL paan_p_Page_08thm.jpg
75173e725e1bab7f2bb5884a158c30fb
858411c66e61057870f526d412ea48e9fe6fa182
F20101124_AACOQN paan_p_Page_36.tif
d4962ad8a4fe9d11e83ea0087c02839c
55fffbb76f65be20561c8f717b11a328b3e2adcc
21463 F20101124_AACOVM paan_p_Page_18.QC.jpg
b425d9a04fe10e7647b323ab6622a124
ab37ba6691761237b4d0c6b322fa1d7b20dc6693
F20101124_AACOQO paan_p_Page_37.tif
2cf21f8561e014b8af781d834c06d8eb
45b0325442ddaa58018826d18430ad55de8885a9
24632 F20101124_AACOVN paan_p_Page_45.QC.jpg
676999d785e0076ac932942e542e9239
b670e7ce8e9920b19f385a1cfd3ceeda6db30b89
F20101124_AACOQP paan_p_Page_38.tif
f5cedad4145c7def7ab22581d939ea73
c452572229521cff7adaedfe4271200ad606252b



PAGE 1

EFFECT OF ALCOHOL COSOLVENTS ON THE AQUEOUS SOLUBILITY OF TOXAPHENE By PADMA PAAN A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2005

PAGE 2

Copyright 2005 by Padma Paan

PAGE 3

Dedicated to my parents, for all I was, am and will be, I owe it to them. They endured financial and social hardships, and defied age-old traditions, to encourage me to explore my own world. I would never have made it this far without their unw avering strength and unconditional love.

PAGE 4

ACKNOWLEDGMENTS I would like to express my sincere gratitude to Dr. Clayton J. Clark II, chairperson of my supervisory committee, for his invaluable guidance and constant encouragement throughout the duration of this work. I would also like to thank my committee members Dr. Angela Lindner and Dr. Kirk Hatfield for their valuable time and suggestions. I greatly appreciate the help and constant guidance of Mr. Xiaosong Chen, PhD student of the hydrology group, in performing laboratory experiments. I also want to thank my family and friends for their emotional support and encouragement throughout my education. iv

PAGE 5

TABLE OF CONTENTS page ACKNOWLEDGMENTS.................................................................................................iv LIST OF TABLES............................................................................................................vii LIST OF FIGURES.........................................................................................................viii ABSTRACT.......................................................................................................................ix CHAPTER 1 INTRODUCTION........................................................................................................1 2 LITERATURE REVIEW.............................................................................................3 Cosolvents and Enhanced Solubility............................................................................3 Factors Affecting Cosolvency...............................................................................5 Water miscibility of cosolvent.......................................................................5 Solute hydrophobicity....................................................................................6 Predicting Cosolvency...........................................................................................7 Log linear model............................................................................................7 UNIFAC model..............................................................................................9 Extended log linear equations......................................................................10 Toxaphene...................................................................................................................11 Composition of Toxaphene.................................................................................12 Toxaphene in Water............................................................................................14 3 MATERIALS AND METHODS...............................................................................16 Materials.....................................................................................................................16 Experimental Methods................................................................................................17 Analytical Methods for Toxaphene............................................................................18 4 RESULTS AND DISCUSSION.................................................................................20 Experimental Results..................................................................................................20 Theoretical Estimations..............................................................................................25 Comparison of Experimental Values with Estimations..............................................26 Future Work................................................................................................................30 v

PAGE 6

5 CONCLUSIONS........................................................................................................31 LIST OF REFERENCES...................................................................................................33 BIOGRAPHICAL SKETCH.............................................................................................37 vi

PAGE 7

LIST OF TABLES Table page 2-1 Chemical/physical properties of toxaphene.............................................................12 3-1 Cosolvent properties.................................................................................................17 4-1 Cosolvency power of toxaphene in water alcohol mixtures.....................................23 4-2 Estimation of cosolvency power for methanol, ethanol and IPA.............................25 4-3 Comparison of experimental cosolvency power with estimated..............................26 4-4 Comparison of experimental toxaphene solubility with estimations in different cosolvents.................................................................................................................27 vii

PAGE 8

LIST OF FIGURES Figure page 2-1 Basic structure of components of toxaphene............................................................13 4-1 Log solubility of toxaphene in water-methanol system as a function of cosolvent volume fraction........................................................................................................20 4-2 Log solubility of toxaphene in water-ethanol system as a function of cosolvent volume fraction........................................................................................................21 4-3 Log solubility of toxaphene in water-IPA system as a function of cosolvent volume fraction........................................................................................................21 4-4 Log solubility of toxaphene in different cosolvents.................................................23 4-5 Linearity between toxaphene solubility and 0-0.2 volume fraction region of methanol...................................................................................................................24 4-6 Comparison of log linear model with experimental values for methanol................28 4-7 Comparison of log linear model with experimental values for ethanol...................28 4-8 Comparison of log linear model with experimental values for IPA........................29 viii

PAGE 9

Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science EFFECT OF ALCOHOL COSOLVENTS ON THE AQUEOUS SOLUBILITY OF TOXAPHENE By Padma Paan August 2005 Chair: Clayton J. Clark II Major Department: Civil and Coastal Engineering Remediation of sites contaminated with chlorinated organic compounds is a significant priority in the environmental field. Traditional pump and treat methods have been found to be inefficient for removal of hydrophobic contaminants from subsurface environments. Research has shown that addition of chemicals known as cosolvents to water increases the aqueous solubility and thus the ease of removal of hydrophobic organic compounds. Toxaphene, a chlorinated hydrophobic organic contaminant, was widely in use as a pesticide until it was banned in 1982 by the USEPA (Environmental Protection Agency). Despite the ban, it is still prevalent in groundwater and is listed by the USEPA as a priority pollutant. The purpose of this research was to evaluate the aqueous solubility of toxaphene as a function of addition of alcohol cosolvents. Experiments were conducted with three completely water miscible alcohols: methanol, ethanol, and isopropyl alcohol. Results showed a log linear increase of toxaphene solubility in water-cosolvent systems as a function of cosolvent fraction added. The ix

PAGE 10

experimental results were compared with estimations using a log linear model from the literature. The logarithm of ratios of solubilities of toxaphene in pure cosolvent and pure water, known as the cosolvency power, for methanol, ethanol, and isopropyl alcohol was found to be 3.5, 3.6 and 4.3, respectively. It was also seen that cosolvency power increased with increasing carbon numbers in cosolvent. Addition of 75% alcohol cosolvents increased the solubility of the toxaphene in water ranging from 300-800%, depending on the cosolvent type. This provides a promising application such as in-situ flushing, in the field of environmental remediation of hazardous sites contaminated with toxaphene. x

PAGE 11

CHAPTER 1 INTRODUCTION Toxaphene is a pesticide that was banned by the United States Environmental Protection Agency (USEPA) in 1982, due to its high toxicity and health hazards (Glassmeyer et al., 1999), and has also identified as a priority pollutants by the USEPA. It has been found in at least 58 of the 1,430 current or former National Priorities List (NPL) sites (Agency for Toxic Substances and Disease Registry [ATSDR], 1996). Due to its hydrophobic nature, toxaphene may be immobilized in the subsurface as entrapped pools, as ganglia in soil macropores, or as a residual saturation in soil micropores. As with most hydrophobic, dense non-aqueous phase liquids, traditional pump and treat methods are not likely to be very effective. Also, the immobilized toxaphene may serve as a long-term source of soil and groundwater contamination due to its slow dissolution in water. Groundwater contamination due to hydrophobic organic compounds continues to be a significant problem in the environmental field. As a result, new remediation techniques including in-situ flushing using cosolvent-water solutions have been demonstrated successfully in the field (Imhoff et al., 1995; Rao et al., 1997; USEPA, 1999). It has been well-established that when added to water, cosolvents increase the solubilization of hydrophobic contaminants in water and hence the rate at which the contaminant can be removed from a contaminated environment (Morris et al., 1988; Falta, 1988; Li and Andren, 1994). In addition to the environmental field, cosolvent-enhanced solubilization was also seen in the fields of enhanced oil recovery and 1

PAGE 12

2 pharmaceutical sciences, where use of smaller molecular weight alcohols has been reported to be effective (Rubino and Yalkowsky, 1987a; Imhoff et al., 1995; Rao et al., 1997). Compounds of interest for environmental cosolvent research to date have been dense non-aqueous phase liquids (DNAPLs) such as trichloroethylene (TCE), tetrachloroethylene (PCE), polychlorinated biphenyls (PCBs), etc. (Pinal et al., 1990; Li and Andren, 1994; Chawla et al., 2001). It is not known whether cosolvent technologies are effective with other compound types, especially pesticides like toxaphene. The purpose of this research was to investigate how the addition of different alcohol cosolvents affected the aqueous solubility of toxaphene. In this investigation, a comparison was conducted between experimentally derived cosolvency powers of different alcohols and their theoretical values estimated from the literature.

PAGE 13

CHAPTER 2 LITERATURE REVIEW Cosolvents and Enhanced Solubility One of the most common groundwater contamination problems is the presence of dense non-aqueous phase liquids (DNAPLs) like trichloroethene (TCE), tetrachloroethene (PCE) and many pesticides. Due to their wide usage in industrial and environmental settings, groundwater at these sites is often contaminated. Removal of these contaminants from groundwater using traditional pump and treat methods, in which contaminated groundwater is pumped out and treated above ground, is not very efficient (Jafvert 1996; USEPA, 1999). There are two primary reasons for the ineffectiveness of pump and treat technologies in removing DNAPLs. Firstly, hydrophobic compounds are tightly held within the pore space of the soil sediments by capillary forces; and secondly, their low aqueous solubility results in a slow rate of removal and necessitates elevated time to achieve remedial objectives (Jafvert 1996; USEPA, 1999). In-situ flushing using alcohol cosolvents or surfactants has been shown to be a solution to the problem of low removal efficiencies of DNAPLs (Imhoff et al., 1995; Rao et al., 1997). Research in this area has shown that cosolvents can promote contaminant removal in a number of complementary mechanisms. First, by increasing the aqueous solubility of the contaminant in water, the mass removal per pore volume is improved and the dissolution process expedited (Banerjee and Yalkowsky, 1988; Pinal et al., 1990; Li and Andren, 1994; Imhoff et al., 1995). The second mechanism is the reduction of the interfacial tension between the water and the contaminant, which may result in physical 3

PAGE 14

4 mobilization of NAPLs (Brandes and Farley, 1993; Rao et al., 1997). In addition to these main mechanisms, others such as the swelling of the NAPL phase relative to the aqueous phase (Brandes and Farley, 1993; Imhoff et al., 1995); and, under certain conditions, complete miscibility of the aqueous and NAPL phases take place (USEPA, 1999). The relative importance of these different mechanisms depends on the phase behavior of the specific system including the water, cosolvent, and NAPL (Falta, 1998). Solubility enhancements caused by cosolvent addition generally occur because of changes in the bulk properties of the isotropic solution (Jafvert, 1996). The addition of cosolvents to water results in a cosolvent effect that affects the ideal equilibrium partitioning relationships. Cosolvents reduce the polarity of the aqueous phase, resulting in reduction in the aqueous phase activity coefficient that allows higher concentrations of hydrophobic solutes to solubilize in the aqueous phase (Groves, 1988). As a water-miscible or partially miscible organic solvent, the cosolvent reduces strong water-water interactions and thereby reduces the ability of water to squeeze out a nonpolar solute (Li et al., 1999). Conversely, there are cosolvents such as chloroform that depress the solubility of the hydrophobic chemicals in water, a polar solvent (Cho et al., 2003). Ladaa et al. (2001) stated that only hydrophilic compounds that are completely miscible in water, such as low molecular weight alcohols and ketones, can be used as cosolvents. In their study that evaluated the cosolvent effects of ethanol, isopropyl alcohol, and tert-butyl alcohol on aqueous solubility of PCE, all three alcohols were observed to increase the aqueous solubility of PCE with tert-butyl alcohol performing better than isopropyl alcohol, which, in turn, performed better than ethanol as a cosolvent. Cosolvency in this case increased with the increase in carbon number in the

PAGE 15

5 cosolvent. According to Jafvert (1996), short-chained linear alcohols are excellent in solubilizing small chlorohydrocarbons, whereas larger hydrocarbon cosolvents work best for larger and more hydrophobic contaminants. Factors Affecting Cosolvency Cosolvency is defined as the effect of the addition of one or more completely water-miscible organic cosolvents on the water solubility of organic compounds (Li and Yalkowsky, 1998). Cosolvency is a phenomenon that can be applied for many purposes in various scientific and engineering fields, such as environmental remediation, pharmaceutical research, etc. (Rubino and Yalkowsky, 1987a; Imhoff et al. 1995). Cosolvency power is used to quantify cosolvency and it is defined as the ratio of solute solubility in a specific organic solvent to the solubility of that solute in pure water as shown below: = log (Sc/Sw) (2-1) where Sc and Sw are the molar solubilities of solute in pure organic cosolvent and in pure water, respectively (Fu and Luthy, 1986; Li et al., 1998b; Pinal et al., 1990; Lee et al., 1993). The values of can be positive, near-zero, or negative, depending on the relative polarity of water, solute, and cosolvent (Li et al., 1998b). There are two main factors that affect cosolvency in solutionthe water solubility of the cosolvent and the solute hydrophobicity. Water miscibility of cosolvent The power of cosolvency is stronger for more highly water-miscible alcohols. According to Ladaa et al. (2001), as the carbon chain length of the alcohols increases, and thus as they become more hydrophobic, their cosolvency power is expected to increase. Li and Andren (1994) studied the solubility of polychlorinated biphenyls (PCB) in

PAGE 16

6 water/alcohol mixtures and found that for a given PCB congener, the solubility enhancement increased with increasing carbon number in the water miscible alcohols used such as methanol, ethanol and IPA. Also, the cosolvency of completely miscible organic solvents (CMOS) increases with decreasing solvent polarity. Pinal and co-workers (1990) investigated the cosolvency of CMOSsmethanol, 2-propanol, acetone, acetonitrite, dioxane, dimethyl sulfoxide on solubility of various hydrophobic organic chemicals, and these authors concluded that the lower the polarity of the solvent, the better its ability to solubilize a hydrophobic solute (Pinal et al., 1990). Rubino and Yalkowsky (1987a) discussed the variation of cosolvency power with different polarity indices such as dielectric constant, solubilization parameter, interfacial tension, surface tension and octanol water partition coefficient. It was concluded that cosolvency power decreased linearly with the increase in all of these parameters except log (octanol water partition coefficient), in which case the trend was in reverse order. Overall, as the polarity of the cosolvent increased, the cosolvency power decreased. Solute hydrophobicity It is also evident that solubility enhancement is related to the degree of chlorination or the hydrophobicity of the organic solutes. The extent of solubility enhancement by the same alcohol increases as the solute hydrophobicity increases. Li and Andren (1994) found that using the same alcohol, methanol, the aqueous solubilities of different PCB congeners were increased to a higher degree in increasing order of the their chlorination. In a 20% methanol solution, the aqueous solubilities of 4-monochlorobiphenyl, 2, 4, 6trichlorobiphenyl and 2, 2, 4, 4', 6, 6'-hexachloroblphenyl were determined to be 3.89, 6.14, and 14.88 times their solubilities in pure water, respectively.

PAGE 17

7 Predicting Cosolvency In addition to experimental data, there are approximations for estimation of solubility enhancement in aqueous solutions due to the addition of cosolvents. Various models are available in literature based on regression analysis from experimental data (Morris et al, 1988; Li et al, 1998b); however, the most widely used is the log linear model (Yalkowsky and Roseman, 1981; Imhoff et al., 1995; Rao et al., 1997) Log linear model The log linear model, proposed by Yalkowsky and Roseman (1981), estimates the solubility of a non polar solute in a mixed (cosolvent-water) solvent (Sm) by ln(Sm) = f ln(Sc) + (1-f) ln(Sw) (2-2) where f is the cosolvent volume fraction and Sc and Sw are the solubilities in pure cosolvent and pure water (Morris et al., 1988). It assumes the absence of specific solute-solvent interactions and is based upon a linear relationship between the free energy of the solution and solute surface area. The solute contacts both water and cosolvent, and the fraction of the solute component is approximately proportional to the volume fraction of that component. Eq. (2-2) can be rewritten as log(Sm) = f log(Sc/Sw) + log(Sw) (2-3) log(Sm) = f + log(Sw) (2-4) Plotting log solubility of hydrophobic solute in water and cosolvent mixture vs. volume fraction of cosolvent used generally results in a straight line, and the slope of this line is referred to as cosolvency power (). Also, there is a correlation between cosolvency power of an organic solvent and the log octanol water partition coefficient (log Kow) of the solute (Li et al., 1998a; Corseuil et

PAGE 18

8 al., 2004). Cosolvency power has been reported by these authors to correlate linearly with the log Kow, as given below: = M Kow + N (2-5) For a specified solute/cosolvent/water system, the regression parameters M and N are specific for the cosolvent and independent of the solutes, and can be viewed as measures of cosolvent polarity (Rubino and Yalkowsky, 1987a; Li et al., 1998a). Eq. (2-2) treats water and cosolvent as two distinct entities and neglects the interaction between them. Sometimes, this approximation cannot hold under conditions where the cosolvent is present at infinite dilution. In these situations, the solute will on average be influenced by only one cosolvent molecule at a time, and any solubility enhancement will be proportional to the number of cosolvent molecules present (Powers et al., 2001). Work by Banerjee and Yalkowsky (1988), and Cho et al. (2003) focusing on cosolvency in dilute systems seems to indicate that the magnitude of the solubility enhancement is linear up to some 10-20% cosolvent fraction. At very low concentrations of cosolvent, the assumption of non-interaction between the cosolvent and water does not hold. In dilute solutions, the individual cosolvent molecules will be fully hydrated and, as a result, will disrupt the water network structure (Grunwald, 1986). If the total volume disrupted is regarded as the extended hydration shell and if Sc* is the average solubility of the solute within this shell, then the overall solubility Sm of the solute in the water-cosolvent mixture will be approximated by Sm = fcVH Sc* + (1fcVH) Sw ; fcVH < 1 (2-6) where VH is the ratio of the hydration shell volume to the volume of the cosolvent (Banerjee and Yalkowsky, 1988).

PAGE 19

9 In dilute solutions, the solute will generally contact only one hydrated cosolvent molecule at a time, and the degree of solubilization should be a linear rather than a logarithmic function of cosolvent content (Banerjee and Yalkowsky, 1988). Thus, it is expected that the log-linear relationship between Sm and fc that applies at high cosolvent concentrations will become linear at low cosolvent levels due to a change in the mechanism of solubilization. UNIFAC model An alternative approach to modeling the solubilities of hydrophobic organic compounds in a cosolvent mixture uses a thermodynamic basis to estimate the activity coefficients of each component in each phase. The activity coefficient of component i, i, is a measure of the extent of deviation from the ideal behavior. These activity coefficients in different phases are then used in a set of equations that equate the chemical activities of a species between the two phases. A model known as UNIFAC divides the activity coefficient, into a combinatorial part, c, which reflects the size and shape of the molecules, and a residual portion r, which depends on the functional group interactions. ln = ln c + ln r (2-7) The basic assumption of UNIFAC is that a physical property of a fluid is due to the sum of contributions made by the molecules functional groups (Li, 2001). The UNIFAC model, allows the necessary parameters to be estimated from the number and type of functional groups that comprise the chemical species (Gupte and Danner, 1987; Pinal et al., 1990; Powers et al., 2001; Li, 2001). One of the major advantages of the UNIFAC model is that two of the assumptions made in the log linear model are not necessary because all the possible interactions are

PAGE 20

10 explicitly considered. Furthermore, calculations of in mixtures with UNIFAC are possible using only pure component data. One disadvantage, however, is that a number of interaction parameters of environmental interest are not yet available. In addition, being a group contribution method, distribution between isomers is not possible with UNIFAC. For ternary solvent systems where mutual solubility is significant, UNIFAC can be implemented into available algorithms for constructing phase diagrams. The composition of each component in each phase as well as the relative amounts of organic and aqueous phases present can be obtained from the phase diagram. Gupte et al. (1987) discussed that UNIFAC predictions are not always very accurate, especially for systems including water and alcohol (Pinal et al., 1990). Extended log linear equations Work by Yalkowsky et al. (1985), Rubino and Yalkowsky (1987b), Morris et al. (1988), and Li and Andren (1994), showed that deviations from the log linear model were also observed in the case of water and miscible cosolvent mixtures, which are considered mainly due to nonideality of the solvent mixture. The nonideality of a mixture is quantitatively measured by the excess free energy of mixing, ln EiGRTX i (2-8) where R is the gas constant, T is the absolute temperature, and Xi is the mole fraction of component i in the solution. The activity coefficient of component i, i, is a measure of the extent of deviation from the ideal behavior. Pinal et al. (1991) proposed that a term 2.303 (fi log i), which is the analogue to (Xi ln i), be added to the simple log linear model to account for the effect of the solvent nonideality. Li (2001) further provided an approach to accurately predict

PAGE 21

11 cosolvency by extending the log linear model. Activity coefficients of the system components are estimated using UNIFAC group contribution method, and the sum of their logarithms weighted by either mole fractions or volume fractions is added to the log-linear model. Four such extended forms were given: Equation I: Log Sm = Log Sw + f + log w + f log(c / w) (2-9) Equation II: Log Sm = Log Sw + f + log w + x log(c / w) (2-10) Equation III: Log Sm = Log Sw + f + ln w + f ln(c / w) (2-11) Equation IV: Log Sm = Log Sw + f + ln w + x ln(c / w) (2-12) where Sm and Sw are the molar solubilities of hydrophobic solute in mixed solvent and pure water, respectively. The constants w and c are activity coefficients of water and cosolvent in a solute-free mixed solvent, respectively. The volume fraction of the cosolvent is labeled f and x is the mole fraction of the cosolvent. The last two terms in the above equations are the infinite dilution activity coefficient of a solute in a solvent mixture expressed as a power series in the volume fractions of solvent components. Toxaphene Toxaphene is identified by CAS# 8001-35-2 and by its United Nations Department of Transportation number, UN# 2761 (USEPA, 1998). Because of its toxicity, persistence and heavy use, toxaphene is one of the dirty dozen, 12 chlorinated compounds designated for international action by the United Nations Environmental Program (ATSDR, 1996). In the United States, about 85% of the toxaphene was used for the control of cotton insect pests, 15% was used to control insect pests on livestock, poultry, and a few field crops other than cotton (IARC, 1979). Toxaphene solutions were often mixed with other pesticides partly because toxaphene solutions appear to help solubilize other insecticides with low water solubility. Toxaphene was frequently applied

PAGE 22

12 with methyl or ethyl parathion and lindane (WHO 1974; IARC 1979; ATSDR, 1996). Table 2-1 gives the physical/chemical properties of toxaphene (ATSDR, 1996). Table 2-1. Chemical/physical properties of toxaphene Property Value or Information Chemical name(s) Toxaphene, camphechlor; chlorinated camphene Chemical formula C10H10Cl8 (average; includes components with 6 to 10 chlorines) Molecular weight 414 (average) CAS number 8001-35-2 USEPA hazardous waste code P123 Trade names Agricide Maggot Killer, Alltox, Camphofene, Huilex, Geniphene, Hercules 3956, Hercules Toxaphene, Motto, Penphene, Phenicide, Phenatox, Strobane-T, Synthetic 3956, Toxakil Color/form/odor Yellow waxy solid with mild turpentine odor Melting pointa 65-90 0C Octanol-water partition coefficient (Kow) 3.3 (Log Kow) Density/specific gravity 1.65 at 25 oC Solubility in water 3 mg/L Composition of Toxaphene Toxaphene is a mixture of chlorinated camphenes that occurs as a waxy yellow or amber solid, with a pleasant odor (Sergeant and Onuska, 1989). It consists of 600 hexato decachlorinated bornanes and bornenes. Toxaphene, also known as chlorinated camphene, is a complex mixture of polychlorobicyclic terpenes, with chlorinated camphenes predominating (67-69% chlorine) (Food and Agricultural Organization [FAO], World Health Organization [WHO], 1968). The source of terpene and the degree of chlorination outside the 67-69 percent range alter the insecticidal activity. The

PAGE 23

13 composition of toxaphene is very complex, consisting of over 32,000 possible congeners, of these, only a limited number of congeners have been individually isolated and characterized. The average empirical formula is C10H10Cl8 (ATSDR, 1996). A double bond is present in some congeners but absent in others and the level of chlorination ranges between 6 and 10. Ten different carbon atoms are present which can be substituted with 1 or 2 chlorines, each leading to a very large number of isomers, many of which are chiral. The basic structure of components in toxaphene is as shown in figure 2-1 (Buser and Muller, 1994). Figure 2-1. Basic structure of components of toxaphene Toxaphene was first synthesized in 1947 by the Hercules Chemical Co. and was patented in 1951 (James and Hites, 2002). The mixture was produced in three steps: (a) the extraction of -pinene from pine stumps, (b) the isomerization of this compound to camphene, and (c) the photochlorination of camphene to produce toxaphene (Rumker et al., 1975). The toxaphene mixtures are prepared commercially as dusts, sprays, and wettable powders and are used alone or in combination with other pesticides for use on cotton and food crops. Toxaphene is now most often produced by the controlled chlorination of camphene (2,2-dimethyl-3-methylene-bicyclo[2.2.1]heptane) under UV light (James and Hites, 2002).

PAGE 24

14 Toxaphene in Water Deposition of airborne toxaphene and/or its direct application to water bodies for the elimination of undesirable species has resulted in the detection of significant quantities in surface waters (ATSDR, 1996). Due to the low water solubility (3 mg/L), a majority of the toxaphene molecules strongly bind to particles and is deposited on sediments; however, there is a presence in groundwater as a result of normal agricultural use. Toxaphene enters surface waters through runoff from rain, by direct application to lakes as a pesticide, by wastewater release from manufacturing facilities, and through activities related to disposal of waste pesticides (James and Hites, 2002). Toxaphene also enters water bodies when it is transported with soil particles. In water, toxaphene appears to be resistant to all forms of degradation. It is not known to undergo photolysis or photo-oxidation. A hydrolytic half-life of 10 years was estimated for water at pH 5 to 8 (ATSDR, 1996). The ability to persist in the environment with little or extremely slow decay, its ability to bioaccumulate (Bioconcentration factor of the order of 10,000) and the general toxicity danger to environment and humans make toxaphene a pollutant of concern (ATSDR, 1996). Toxaphene has been detected at hazardous waste sites in surface water, groundwater, and leachates (ATSDR, 1996). Toxaphene was detected at a maximum concentration of 17 ppb in surface water samples taken from 2 of 9 disposal ponds at a Super-fund site (USEPA 1986). In a study of the chemical composition of leachates within existing landfills, toxaphene was not detected in any of the municipal landfill leachates examined; however, the mixture was detected in industrial landfill leachates at a concentration of 10 ppb. In a review of groundwater monitoring data collected in 1981-1984 from more than 500 wells at 334 hazardous waste disposal sites (RCRA and

PAGE 25

15 CERCLA sites) located in all 10 USEPA regions and 42 states, Plumb (1987) reported that toxaphene was detected at 0.2% frequency at the 178 CERCLA sites examined and at 1.1% frequency at the 156 RCRA sites examined. Toxaphene has also been detected in surface water samples from 12 of 58 NPL sites, in groundwater samples from 20 of 58 NPL sites and in leachate samples from 1 of 58 NPL sites where toxaphene has been detected in some environmental media; however, concentrations were not reported (ATSDR 1996).

PAGE 26

CHAPTER 3 MATERIALS AND METHODS Enhanced solubilization of toxaphene by addition of alcohol cosolvents in the water was evaluated by performing batch experiments according to Pinal et al. (1990) but changed for toxaphene according to analytical methods for toxaphene using USEPA method 8081B, which suggests the total area approach for toxaphene analysis using a gas chromatograph fitted with an electron capture detector (GC-ECD). Materials Toxaphene was obtained from Chem Service, West Chester, PA as a mix of isomers and was used as received for batch tests. For GC-ECD analytical calibration curve, toxaphene was obtained from AccuStandard with a concentration of 1000-ppm in hexane matrix. Methanol, ethanol, and IPA were chosen as cosolvents in this research. They were used as received from Fisher-Scientific. Alcohols with higher carbon numbers were found to be only partially miscible in water and hence were not used. The following criteria were used for the selection of cosolvents for this research and were similar to those considered by Chawla et al. (2001) a) non-toxic, b) biodegradable, c) completely miscible with water, d) relatively inexpensive; and e) commonly available. Physical/chemical properties of the cosolvents, methanol, ethanol and IPA are provided in Table 3-1 (Chawla et al., 2001). 16

PAGE 27

17 Table 3-1. Cosolvent properties Property Methanol Ethanol IPA Boiling point (C) 65 79 80 Vapor pressure at 20 C (mm Hg) 127 40 33 Specific gravity at 20 C 0.791 0.79 0.786 Solubility in water 100% 100% 100% Carcinogenicity No No No Biodegradability in soil Readily Readily Moderately Biodegradability in water Readily Readily Moderately Half life in soil (days) 1-10 N/A 1-10 Environmental toxicity Slightly toxic Not toxic Not toxic LD50 (mg/kg) 5628 7060 5045 Bioaccumulation No No No Price ($/200L) 672.50 917.80 868.15 Dipole moment (debye) (Lide, 1996) 1.70 1.69 1.58 Experimental Methods Cosolvent solutions, over a wide range of concentrations (10%, 20%, 30%, 40%, 50%, 60%, and 75% alcohol by volume), were prepared by adding methanol/ethanol/IPA separately in water in 50 ml flasks. Samples were prepared in 5 ml glass vials fitted with a Teflon-coated, septum-lined screw cap to prevent potential volatilization. Each vial was weighed empty; and 5 mg of toxaphene was then added to each vial and the vials were weighed again. The vials were subsequently filled with cosolvent solutions allowing no headspace and reweighed. All samples were prepared in triplicate. Samples were then placed on a rotator (40% revolution, 24 rpm) for about a 24-hr equilibrium period. Tests were conducted for equilibrium period of 1 week, results from which did

PAGE 28

18 not show a significant difference from those of the equilibrium period of 24 hrs; hence it was assumed that the equilibrium was reached. A known volume (2 ml for 0%, 10% and 20%, 1 ml for 30% and 40%, and 0.5 ml for 50%, 60% and 75% cosolvent concentration) of these solutions was transferred to other 5 ml glass vials for volatilization. After approximately 48 hrs, a known volume of hexane was added to the vials, which were then put on the rotator. After about 24 hrs, two layers could distinctly be seen in the vials. Samples from the upper layer containing hexane and toxaphene were used for GC-ECD analysis. Analytical Methods for Toxaphene GC-ECD is the most frequently used analytical method for characterization and quantification of toxaphene in air, drinking water, fish, and other environmental samples. Analysis of the sample includes extraction in organic solvent; a Florisil silica, gel permeation, or TLC clean-up step; and detection by GC. It is also the standardized method used by USEPA (method 8081B) for determining toxaphene in water and soil samples. A typical gas chromatogram contains a series of hills and valleys with three main peaks (USEPA, 1998; Clark et al., In press). While toxaphene contains a large number of compounds that will produce well-resolved peaks in a GC-ECD chromatogram, it also contains many other components that are not chromatographically resolved. Although, the resolved peaks are important for the identification of the mixture, the area of the unresolved complex mixture contributes a significant portion of the area of the total response (USEPA, 1998). For the above reason, the area under the curve is used for the quantitation of total toxaphene (USEPA, 1998; Clark et al., In press). Detection limits of 0.086 g/L of water and 5.7 g/kg of soil were reported for toxaphene (ATSDR, 1996).

PAGE 29

19 For this research, GC-17A Shimadzu equipped with DB-30 column and a 63Ni electron capture detector was used for analysis of samples. The program was set for calculating constant velocity and total area approach was used for measuring the toxaphene present in the hexane extracted aqueous phase. Concentration of toxaphene in each solution was determined from an 8-point calibration curve, ranging from 0.2-50 ppm of toxaphene concentration, developed experimentally using known standard toxaphene solution. Samples were diluted to bring the solute concentrations within this range.

PAGE 30

CHAPTER 4 RESULTS AND DISCUSSION Toxaphene solubility in binary water-cosolvent solutions was determined experimentally by performing batch experiments. In addition, the cosolvency powers for toxaphene solubilized in different alcohols/water systems were determined using the experimental results from the batch tests and compared with theoretical values predicted from the literature. Experimental Results Toxaphene concentrations in the cosolvent-water mixture were obtained using GC-ECD methods as previously described. Solubility of toxaphene was plotted as a function of the volume fraction of the cosolvents (Figures 4-1 4-3): Methanol as cosolventSlope = 3.46 R2 = 0.990123400.20.40.60.81Volume fraction cosolventlog solubility (ppm) Figure 4-1. Log solubility of toxaphene in water-methanol system as a function of cosolvent volume fraction 20

PAGE 31

21 Ethanol as cosolventSlope = 3.60R2 = 0.980123400.20.40.60.81Volume fraction cosolventlog solubility (ppm) Figure 4-2. Log solubility of toxaphene in water-ethanol system as a function of cosolvent volume fraction IPA as cosolventSlope = 4.30R2 = 0.980123400.20.40.60.81Volume fraction cosolventlog solubility (ppm) Figure 4-3. Log solubility of toxaphene in water-IPA system as a function of cosolvent volume fraction In Figures 4-1 4-3, each datum point represents the logarithm of single batch test solubility result and each error bar represents a fixed value of 0.1. These log-linear plots show that the aqueous solubility of toxaphene increases with an increase in volume

PAGE 32

22 fraction (f) of cosolvent in the solution. This trend is similar to the previous works on solubility of PCBs, PCE and other chlorinated compounds (Yalkowsky et al., 1985; Pinal et al., 1990; Li and Andren, 1994; Chawla et al., 2001). Previously mentioned, the slopes of these plots (Figures 4-1 4-3) represent the cosolvency powers of the cosolvents, which is the parameter used for evaluation of the effectiveness of the cosolvent in enhancing solubilization of toxaphene in water (Pinal et al., 1990). Therefore, solvents with higher cosolvency power values solubilize more contaminant for equivalent amount of volume fraction in binary solution. It was observed from plots (Figures 4-1 4-3), that they display two distinctive regions, divided at a volume fraction of 0.2. More specifically, slope of the line f < 0.2 is usually less than the slope of the line f > 0.2. For clarification, solubility values at each fraction of cosolvent, f, were averaged and then plotted as shown in Figure 4-4, which clearly shows the two parts of the curve for each cosolvent, similar to observations have been made by Banerjee and Yalkowsky (1988), Morris et al. (1988), Pinal et al. (1990) and Li and Andren (1994). Banerjee and Yalkowsky (1988) attributed this to the hydration of cosolvent molecules in dilute solutions, and interaction between hydrated shells of the cosolvent molecules.

PAGE 33

23 Log solubility of toxpahene in different cosolvents0123400.20.40.60.8Volume fraction cosolventlog solubility (ppm) Methanol Ethanol IPA Figure 4-4. Log solubility of toxaphene in different cosolvents Cosolvency powers of toxaphene in binary solutions containing water for methanol, ethanol and IPA were determined and listed in Table 4-1. Table 4-1. Cosolvency power of toxaphene in water alcohol mixtures Cosolvent Fraction range Cosolvency power R2 Overall cosolvency power R2 0 0.2 2.71 0.94 Methanol 0.2 0.75 3.63 0.99 3.46 0.99 0 0.2 4.00 0.80 Ethanol 0.2 0.75 3.79 0.98 3.60 0.98 0 0.2 2.97 0.98 IPA 0.2 0.75 4.37 0.95 4.30 0.98 Results indicate that toxaphene cosolvency was directly related to the number of carbons in the cosolvent utilized. As the number of carbon atoms in the cosolvent increases, so did the toxaphene solubility. A similar trend was observed by Ladaa et al. (2001) and, Li and Andren (1994). The following trend was observed for this research: IPA > ethanol > methanol

PAGE 34

24 It was found that the cosolvency of toxaphene in the aqueous solution increased with decreasing solvent polarity in agreement with Pinal et al. (1990). Methanol was most polar (highest dipole moment; Table 3-1) among the three alcohols used and was found to be least effective in solubilization of toxaphene. It has a smaller non-polar alkyl group than ethanol and IPA, and, hence, its ability to reduce the polarity of the whole solution is less than other two alcohols, as a result, its cosolvency on the solubility of the toxaphene was the least. Also, it was found that for methanol fractions less than 20%, the relationship between solubility and volume fraction of methanol is linear. The similar observation for methanol was also seen by Banerjee and Yalkowsky (1988), and Li (2001). These differences are attributed to the hydration of the cosolvent molecules at low concentrations (Banerjee and Yalkowsky, 1988). This trend was only seen for methanol, perhaps because methanol has a smaller molecular weight and size, it may become integrated into water structure better than other two cosolvents, which tend to perturb the water network (Grunwald, 1986; Rubino and Yalkowsky, 1987b). Linearit y between solubilit y and volume fraction of methanol0481200.1Volume fraction cosolventSolubility (ppm)) 0.2 Figure 4-5. Linearity between toxaphene solubility and 0-0.2 volume fraction region of methanol

PAGE 35

25 Theoretical Estimations Cosolvency power can also be estimated using its relationship with log (octanol water partition coefficient) using the relationship: = a log P + b (4-1) Where P is the octanol/water partition coefficient of the solute and a, b are the regression parameters (slope and y-intercept) obtained from the vs. log P curve (Morris et al., 1988). For toxaphene, the value of log P of 3.3 was used for these estimations (ATSDR, 1996). Estimated values of cosolvency power for methanol, ethanol and IPA are as listed in Table 4-2. Table 4-2. Estimation of cosolvency power for methanol, ethanol and IPA Cosolvency power Cosolvent Morris et al., 1988 Li et al., 1998b Methanol 3.31 3.16 3.43 Ethanol 3.62 3.33 3.54 IPA 3.57 2.75 3.57 Based on cosolvency power and using the log linear model, the solubility of toxaphene can also be estimated in the presence of different volume fractions of different cosolvents. Toxaphene solubility in different water-cosolvent systems were determined theoretically using the log linear model (Equation 2-4) by substituting the value of toxaphene solubility in pure water (3 ppm, ATSDR 1996) and cosolvency power values (Table 4-2). Equation 2-2b takes the final form for different cosolvents as shown below (Equations 4-2 4-4): Methanol: Log(Sm)est = 3.31*f + log (3) (4-2) Ethanol: Log(Sm)est = 3.62*f + log (3) (4-3) IPA: Log(Sm)est = 3.57*f + log (3) (4-4)

PAGE 36

26 Comparison of Experimental Values with Estimations Values of cosolvency powers for methanol, ethanol and IPA were estimated from data available in literature. These estimated values of cosolvency powers were plotted and compared with experimental results from solubility batch tests. The percentage difference between estimated values and experimental values were also calculated using the following relationship, exp)est)exp)(-)*100% difference= (4-5) Table 4-3. Comparison of experimental cosolvency power with estimated Cosolvency power Cosolvent Estimated (est) Experimental (exp) % Difference Methanol 3.31 3.46 4.34 Ethanol 3.62 3.60 -0.56 IPA 3.57 4.30 16.98 There was a discrepancy found in estimated and experimental cosolvency powers of IPA, which may be due to the branched nature of the IPA molecule compared to the other straight-chain alcohols. Cho et al. (2002) studied the effect of molecular structures of surfactants on the solubility enhancement of polycyclic aromatic compounds and found that surfactants with a bulky polar heads were somewhat less efficient for solute solubilization. Overall, research in this field seems to be limited and requires further exploration. For the straight chain alcohols, methanol and ethanol, theoretical and experimental values of cosolvency power, are within a range of 95-100%. Toxaphene solubility obtained theoretically using equations 4-2 4-4 were compared with experimental values as shown in Table 4-4, where log(Sm)exp and log(Sm)est are the logarithms of toxaphene solubility in ppm in mixed water-cosolvent

PAGE 37

27 system, obtained experimentally and estimated from log linear model. Each (Sm)exp is the mean of at least 2 experimental values of solubility. Diff. is the difference between log(Sm)exp and log(Sm)est. Table 4-4. Comparison of experimental toxaphene solubility with estimations in different cosolvents Methanol Ethanol IPA f log(Sm)exp log(Sm)est Diff. Log(Sm)exp Log(Sm)est Diff. log(Sm)exp Log(Sm)est Diff. 0 0.48 0.48 0.00 0.46 0.48 -0.01 0.52 0.48 0.04 0.1 0.83 0.81 0.02 1.16 0.84 0.32 0.82 0.83 -0.01 0.2 0.99 1.14 -0.15 1.27 1.20 0.06 1.11 1.19 -0.08 0.3 1.43 1.47 -0.04 1.59 1.56 0.02 1.67 1.55 0.13 0.4 1.72 1.80 -0.08 1.86 1.93 -0.06 2.34 1.91 0.43 0.5 2.17 2.13 0.04 2.48 2.29 0.19 2.78 2.26 0.52 0.6 2.59 2.46 0.12 2.75 2.65 0.10 3.17 2.62 0.55 0.75 3.01 2.96 0.05 3.30 3.19 0.11 3.45 3.15 0.30 Average absolute difference 0.06 0.11 0.26 Results in Table 4-4 show that the solubility of toxaphene was increased from 3 ppm in pure water to 1000-2000 ppm for high concentrations of cosolvents, varying with the cosolvent. Average absolute difference was calculated for each cosolvent. These differences or deviations from log linear model were generally negative for dilute solutions and positive for higher volume fractions of cosolvent, similar to results reported by Rubino and Yalkowsky (1987b) and Li (2001). To further quantify these deviations, log linear model was modified as with the equations offered by Li (2001). Extended log linear equations described in Chapter 2 were plotted and compared with experimental results, as shown in the Figures 4-6 4-8.

PAGE 38

28 Best fit for methanol0.00.51.01.52.02.53.00.00.20.40.60.81.0Volume fraction cosolventLog (Sm/Sw) Experimental Log linear Extended log linear I Extended log linear II Extended log linear III Extended log linear IV Figure 4-6. Comparison of log linear model with experimental values for methanol Best fit for ethanol0.00.51.01.52.02.53.03.50.00.20.40.60.81.0Volume fraction cosolventLog (Sm/Sw) Experimental Log linear Extended log linear I Extended log linear II Extended log linear III Extended log linear IV Figure 4-7. Comparison of log linear model with experimental values for ethanol

PAGE 39

29 Best fit for IPA0.00.51.01.52.02.53.03.50.00.20.40.60.81.0Volume fraction cosolventLog (Sm/Sw) Experimental Log linear Extended log linear I Extended log linear II Extended log linear III Extended log linear IV Figure 4-8. Comparison of log linear model with experimental values for IPA Equations 2-9 2-12 were used and the mole fraction, x, of the cosolvent was calculated on the basis of solute-free solvent mixture. Activity coefficients for different mole fractions and different cosolvents were taken from Li (2001). Average absolute differences in estimations from different extended log linear equations and experimental results were calculated in a similar fashion as done previously for log linear model and experimental results. For methanol, none of the extended equations generate improved solubility estimates than the original log linear model. For ethanol, extended log linear equation II gives the best results, and the lowest average absolute difference. For IPA, however, the trend has a jump from log linear for the low cosolvent fractions (f <0.3) to extended log linear equation III. These extended log linear equations give estimated solubility in mixed solvent higher than log linear model because of the additional terms in the equations which take

PAGE 40

30 nonideality of solvent mixture into consideration. Therefore, the extended log linear model did not improve the negative deviations from log linear model, however the positive deviations were improved in case of methanol, ethanol, and greatly in case of IPA. Overall, toxaphene solubility in water increased significantly with addition of cosolvent. The log linear model can be used for predicting the cosolvency power and, therefore, the solubility of toxaphene in other water-cosolvent solutions as well. Results from this research have promising applications in the field of environmental remediation using in-situ flushing and studies of fate and transport of pollutants. The results from this research has a limitation to field application, Since cosolvency of alcohols also depends on the solute hydrophobicity (Yalkowsky et al., 1985; Li and Andren, 1994), toxaphene in the field sites can have a different chlorine atom number and hence different hydrophobicity levels than that were explored in the present research. Pilot studies could be performed using samples from the site under consideration. Future Work As it was concluded from this research that toxaphene cosolvency increases with increase in carbon numbers in the cosolvent, higher molecular weight alcohols (e.g., butanol, pentanol etc.) should be used for further research in order to quantify the deviations from log linear model. Effect of branched and straight chain alcohols on aqueous solubility of toxaphene can also be evaluated.

PAGE 41

CHAPTER 5 CONCLUSIONS The purpose of this research was to evaluate the effectiveness of alcohol cosolvents in enhancing the solubility of toxaphene in water. Batch experiments were conducted for toxaphene solubility in binary water-cosolvent solutions, including methanol, ethanol and IPA. It was concluded that alcohol cosolvents do indeed increase the solubility of toxaphene in water, sometimes on the order of hundred-fold increase. Plots of toxaphene solubility in mixed solvent vs. volume fraction of cosolvent in the mixed solvent showed a log linear relationship. The cosolvency power was determined and found to be within the range of 83-100% of the values estimated from literature. Methanol showed linearity for the above-mentioned plot for cosolvent fractions less than 20% which was attributed to its lower molecular weight. Deviations from the log linear model were observed, similar to what has been seen in the literature as well. Approaches from literature were used to modify the log linear model to more accurately predict the toxaphene cosolvency. It was found that for methanol none of the approaches used gave less average absolute difference than the log linear. For ethanol, one of the approaches based on the nonideality of the solvent mixture gave better match with experimental results. For IPA, the experimental values moved from the log linear to modified log linear. Comparing the effect of different alcohols, it was found that with increasing carbon number in the cosolvent, the solubility enhancement was increased. IPA is more polar than ethanol, which in turn is more polar than methanol. The performance of the 31

PAGE 42

32 cosolvents in increasing aqueous solubility of toxaphene was in reverse order of their polarity. Overall, this research proved the potential of alcohol cosolvents in increasing aqueous solubility of toxaphene. Prospective applications of this research are in the field of environmental remediation of hazardous sites or aquifers contaminated with toxaphene by in-situ flushing.

PAGE 43

LIST OF REFERENCES Agency for Toxic Substances and Disease Registry (ATSDR), 1996. Toxicological Profile for Toxaphene (Update), U.S. Department of Health and Human Services, Public Health Service, August, Atlanta, GA. Banerjee S, Yalkowsky S H, 1988. Cosolvent-induced Solubilization of Hydrophobic Compounds into Water, Analytical Chemistry, 60, 2153-2155. Brandes D, Farley K, 1993. Importance of Phase Behavior on the Removal of Residual DNAPLs from Porous Media by Alcohol Flooding. Water Environmental Research, 65, 896-878. Chawla R C, Doura K F, McKay D, 2001. Effect of Alcohol Cosolvents on the Aqueous Solubility of Trichloroethylene. Proceedings of the 2001 Conference on Environmental Research, Kansas State University, Manhattan, Kansas, 52-66. Cho J, Annable M D, Rao P S C, 2003. Residual Alcohol Influence on NAPL Saturation Estimates based on Partition Tracers. Environmental Science and Technology, 37, 1639-1644. Clark II C J, Chen X, Babu S, In Press. Degradation of Toxaphene by Zero-Valent Iron and Bimetallic Substrates. Journal of Environmental Engineering. Corseuil H X, Kaipper B I A, Fernandes M, 2004. Cosolvency Effect in Subsurface Systems Contaminated with Petroleum Hydrocarbons and Ethanol. Water Research, 38, 1449-1456. Falta RW, 1998. Using Phase Diagrams to Predict the Performance of Cosolvent Floods for NAPL Remediation, Ground Water Monitoring and Remediation, 18 (3), 94-102. Food and Agricultural Organization (FAO) of the United Nations, World Health Organization (WHO), 1968. Evaluations of Some Pesticide Residues in Food, The Monographs, Joint Meeting on Pesticide Residues, International Programme on Chemical Safety, Geneva. Fu J K, Luthy R G, 1986. Aromatic Compound Solubility in Solvent/Water Mixtures. Journal of Environmental Engineering, 112 (2), 328-345. Glassmeyer S T, Shanks K E, Hites R A, 1999. Automated Toxaphene Quantitation by GC/MS. Analytical Chemistry, 71, 1448-1453. 33

PAGE 44

34 Groves F R, 1988. Effects of Cosolvents on the Solubility of Hydrocarbons in Water. Environmental Science and Technology, 22 (3), 282-286. Grunwald E, 1986. Thermodynamic Properties of Nonpolar Solutes in Water and the Structure of Hydrophobic Hydration Shells. Journal of American Chemical Society, 108, 5726-5731. Gupte P A, Danner R P, 1987. Prediction of Liquid-Liquid Equilibria with UNIFAC: a Critical Evaluation. Industrial & Engineering Chemistry Research, 26, 2036-2042. International Agency for Research on Cancer (IARC), 1979. Second Annual Report on Carcinogens, 20, Geneva. Imhoff P T, Glyzer S, McBride J, Vancho L, Okuda I, Miller T, 1995. Cosolvent-Enhanced Remediation of Residual Non-Aqueous Phase Liquids: Experimental Investigation. Environmental Science and Technology, 29, 1966-1975. Jafvert C T, 1996. Technology Evaluation Report: Surfactants/Cosolvents. TE-96-02, Ground-Water Remediation Technologies Analysis Center, Pittsburgh, PA. James R R and Hites R A, 2002. Atmospheric Transport of Toxaphene from the Southern United States to the Great Lakes Region. Environmental Science and Technology, 36 (16), 3474-3481. Ladaa T I, Lee C M, Coates J T, Falta R W Jr, 2001. Cosolvent Effects of Alcohols on the Henrys Law Constant and Aqueous Solubility of Tetrachloroethylene (PCE). Chemosphere, 44, 1137-1143. Lee L S, Bellin C A, Pinal R, Rao P S C, 1993. Cosolvent Effects of Sorption of Organic Acids by Soils from Mixed Solvents. Environmental Science and Technology, 27, 165-171. Li A, 2001. Predicting cosolvency. 3. Evaluation of Extended Log Linear Model. Industrial & Engineering Chemistry Research. 40, 5029-5035. Li A, Andren A W, 1994. Solubility of Polychlorinated Biphenyls in Water/Alcohol Mixtures. 1. Experimental data. Environmental Science and Technology, 28 (1), 47-52. Li A, Yalkowsky S H, 1998a. Predicting Cosolvency. 1. Solubility Ratio and Solute Log Kow. Industrial & Engineering Chemistry Research. 37, 4470-4475. Li A, Yalkowsky S H, 1998b. Predicting Cosolvency. 2. Correlation with Solvent Physicochemical Properties. Industrial & Engineering Chemistry Research. 37, 4476-4480.

PAGE 45

35 Li P, Zhao L, Yalkowsky S H, 1999. Combined Effect of Cosolvent and Cyclodextrin on Solubilization of Non Polar Drugs. Journal of Pharmaceutical Sciences, 88 (11), 1107-1111. Lide D R, 1996. CRC Handbook of Chemistry and Physics, 76th Ed, 1995-1996. CRC Press, Boca Raton, Fl. Morris K R, Abramowitz R, Pinal R, Davis P, Yalkowsky S H, 1988. Solubility of Aromatic Pollutants in Mixed Solvents. Chemosphere, 17, 285-298. Pinal R, Rao P S C, Lee L S, Cline P V, 1990. Cosolvency of Partially Miscible Organic Solvents on the Solubility of Hydrophobic Organic Chemicals. Environmental Science and Technology, 24(5), 639-647. Pinal R, Lee S L, Rao P S C, 1991. Prediction of the Solubility of Hydrophobic Compounds in Nonideal Solvent Mixtures, Chemosphere, 22, 939-951. Plumb R H, 1987. A Comparison of Ground Water Monitoring Data from CERCLA and RCRA Sites. Ground Water Monitoring Review, 7, 94-100. Powers S E, Hunt C S, Heermann S E, Corseuil H X, Rice D, Alvarez P J J, 2001. The Transport and Fate of Ethanol and BTEX in Groundwater Contaminated by Gasohol. Critical Review in Environmental Science and Technology, 31 (1), 79-123. Rao P S C, Annable M D, Sillan R K, Dai D, Hatfield K, Graham W D, Wood A L, Enfield C G, 1997. Field-Scale Evaluation of In Situ Cosolvent Flushing for Enhanced Aquifer Remediation. Water Resources Research, 33 (12), 2673-2686. Rubino J T, Yalkowsky S H, 1987a. Cosolvency and Cosolvent Polarity. Pharmaceutical Research, 4 (3), 220-230. Rubino J T, Yalkowsky S H, 1987b. Cosolvency and Deviations from Log Linear Solubilization. Pharmaceutical Research, 4 (3), 231-236. Rumker V, Lawless W, Neiners A F, Lawrence K A, Kelso G C, Horaz F, 1975. A Case Study of the Efficiency of the Use of Pesticides on Agriculture. USEPA 540/9-75-025, Washington, DC. Sergeant D B, Onuska F, 1989. Analysis of Trace Organics in the Aquatic Environment. CRC Press, Boca Raton, FL, 69-118. United States Environmental Protection Agency (USEPA), 1986. Superfund Record of Decision (USEPA region 4) Gallaway Ponds Site. USEPA/ROD/R04-X6/013, Gallaway, TN.

PAGE 46

36 United States Environmental Protection Agency (USEPA), 1998. Method 8081B: Organochlorine Pesticides by Gas Chromatography. Test Methods for Evaluating Solid Waste, Physical/Chemical Methods. Revision 2, Washington, DC. United States Environmental Protection Agency (USEPA), 1999. In Situ Enhanced Source Removal. Project Completion Report. USEPA/600/C-99/002, Ada, OK. Yalkowsky S H, 1985. Solubility of Organic Solutes in Mixed Aqueous Solvent. Project Completion Report, USEPA CR811852-01-0, Ada, OK Yalkowsky S H, Roseman T J, 1981. Techniques of Solubilization of Drugs. Marcel Dekker, New York, 91-134.

PAGE 47

BIOGRAPHICAL SKETCH Padma Paan was born in 1980 in Dhamnod, Madhya Pradesh, India. She did her undergraduate studies in civil engineering and received a Bachelor of Technology degree from the Indian Institute of Technology (IIT) Bombay, India, in 2003. In the spring of 2004, she joined the University of Florida for a Master of Science degree in the Department of Civil and Coastal Engineering under the tutelage of Dr. Clayton J. Clark II. 37


Permanent Link: http://ufdc.ufl.edu/UFE0011373/00001

Material Information

Title: Effect of Alcohol Cosolvents on the Aqueous Solubility of Toxaphene
Physical Description: Mixed Material
Copyright Date: 2008

Record Information

Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
System ID: UFE0011373:00001

Permanent Link: http://ufdc.ufl.edu/UFE0011373/00001

Material Information

Title: Effect of Alcohol Cosolvents on the Aqueous Solubility of Toxaphene
Physical Description: Mixed Material
Copyright Date: 2008

Record Information

Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
System ID: UFE0011373:00001


This item has the following downloads:


Full Text












EFFECT OF ALCOHOL COSOLVENTS ON THE AQUEOUS
SOLUBILITY OF TOXAPHENE


















By

PADMA PAAN


A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE

UNIVERSITY OF FLORIDA


2005

































Copyright 2005

by

Padma Paan

































Dedicated to my parents, for all I was, am and will be, I owe it to them. They endured
financial and social hardships, and defied age-old traditions, to encourage me to explore
my own world. I would never have made it this far without their unwavering strength and
unconditional love.















ACKNOWLEDGMENTS

I would like to express my sincere gratitude to Dr. Clayton J. Clark II, chairperson

of my supervisory committee, for his invaluable guidance and constant encouragement

throughout the duration of this work. I would also like to thank my committee members

Dr. Angela Lindner and Dr. Kirk Hatfield for their valuable time and suggestions. I

greatly appreciate the help and constant guidance of Mr. Xiaosong Chen, PhD student of

the hydrology group, in performing laboratory experiments.

I also want to thank my family and friends for their emotional support and

encouragement throughout my education.
















TABLE OF CONTENTS

page

A C K N O W L E D G M E N T S ................................................................................................. iv

LIST OF TA BLE S .............................. ....... ...... .. .............. .. vii

LIST OF FIGURES ...................................................... ................... viii

ABSTRACT .............. .......................................... ix

CHAPTER

1 IN TRODU CTION ................................................. ...... .................

2 LITER A TU R E REV IEW ............................................................. ....................... 3

Cosolvents and Enhanced Solubility ........................................ ........................ 3
Factors A affecting Cosolvency ..................................................... ...... ......... 5
W after m iscibility of cosolvent ............................................ .....................5
Solute hydrophobicity ............................................................................. 6
Predicting Cosolvency .............................................. .. ......... ........ .. ..
L og linear m odel ................... .. ........................ .. ....... ................ .7
U N IFA C m odel .................................. .... ............ .... .
Extended log linear equations ............................. ..... ....... ............... 10
T o x ap h en e ............................................................................................................ 1 1
Com position of Toxaphene ........................................ ........................... 12
T oxaphene in W ater ..................... .. ...... .................. ....... .... ...........14

3 M ATERIALS AND M ETHOD S ........................................ ......................... 16

M a te ria ls .......................................................................................................1 6
E xperim ental M ethods........................................................................ .................. 17
Analytical M methods for Toxaphene .................................. .............................. ...... 18

4 RESULTS AND DISCU SSION ........................................... .......................... 20

E xperim mental R results ............................................................................ ........... 20
Theoretical E stim nations ............. .............................................. ......... ...... 25
Comparison of Experimental Values with Estimations............................................26
F u tu re W o rk ...................................................... ................ 3 0



v









5 C O N C L U SIO N S ..................... .... .......................... .. .... ........ .... ......... ..3 1

L IST O F R E FE R E N C E S ............................................................................. .............. 33

B IO G R A PH IC A L SK E T C H ...................................................................... ..................37
















LIST OF TABLES


Table page

2-1 Chemical/physical properties of toxaphene .................. ............ ...............12

3-1 Cosolvent properties........................................................... .. ............... 17

4-1 Cosolvency power of toxaphene in water alcohol mixtures................................23

4-2 Estimation of cosolvency power for methanol, ethanol and IPA...........................25

4-3 Comparison of experimental cosolvency power with estimated............................26

4-4 Comparison of experimental toxaphene solubility with estimations in different
cosolvents ..................................... ................................. ........... 27
















LIST OF FIGURES


Figure p

2-1 Basic structure of components of toxaphene ............... .................... ............... 13

4-1 Log solubility of toxaphene in water-methanol system as a function of cosolvent
volume e fraction .......................................................................20

4-2 Log solubility of toxaphene in water-ethanol system as a function of cosolvent
volume e fraction .......................................................................2 1

4-3 Log solubility of toxaphene in water-IPA system as a function of cosolvent
volume e fraction .......................................................................2 1

4-4 Log solubility of toxaphene in different cosolvents..............................................23

4-5 Linearity between toxaphene solubility and 0-0.2 volume fraction region of
m eth a n o l .......................................................................... 2 4

4-6 Comparison of log linear model with experimental values for methanol ...............28

4-7 Comparison of log linear model with experimental values for ethanol ...................28

4-8 Comparison of log linear model with experimental values for IPA ......................29















Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science

EFFECT OF ALCOHOL COSOLVENTS ON THE AQUEOUS
SOLUBILITY OF TOXAPHENE

By

Padma Paan

August 2005

Chair: Clayton J. Clark II
Major Department: Civil and Coastal Engineering

Remediation of sites contaminated with chlorinated organic compounds is a

significant priority in the environmental field. Traditional pump and treat methods have

been found to be inefficient for removal of hydrophobic contaminants from subsurface

environments. Research has shown that addition of chemicals known as cosolvents to

water increases the aqueous solubility and thus the ease of removal of hydrophobic

organic compounds. Toxaphene, a chlorinated hydrophobic organic contaminant, was

widely in use as a pesticide until it was banned in 1982 by the USEPA (Environmental

Protection Agency). Despite the ban, it is still prevalent in groundwater and is listed by

the USEPA as a priority pollutant. The purpose of this research was to evaluate the

aqueous solubility of toxaphene as a function of addition of alcohol cosolvents.

Experiments were conducted with three completely water miscible alcohols: methanol,

ethanol, and isopropyl alcohol. Results showed a log linear increase of toxaphene

solubility in water-cosolvent systems as a function of cosolvent fraction added. The









experimental results were compared with estimations using a log linear model from the

literature. The logarithm of ratios of solubilities of toxaphene in pure cosolvent and pure

water, known as the cosolvency power, for methanol, ethanol, and isopropyl alcohol was

found to be 3.5, 3.6 and 4.3, respectively. It was also seen that cosolvency power

increased with increasing carbon numbers in cosolvent. Addition of 75% alcohol

cosolvents increased the solubility of the toxaphene in water ranging from 300-800%,

depending on the cosolvent type. This provides a promising application such as in-situ

flushing, in the field of environmental remediation of hazardous sites contaminated with

toxaphene.














CHAPTER 1
INTRODUCTION

Toxaphene is a pesticide that was banned by the United States Environmental

Protection Agency (USEPA) in 1982, due to its high toxicity and health hazards

(Glassmeyer et al., 1999), and has also identified as a priority pollutants by the USEPA.

It has been found in at least 58 of the 1,430 current or former National Priorities List

(NPL) sites (Agency for Toxic Substances and Disease Registry [ATSDR], 1996). Due

to its hydrophobic nature, toxaphene may be immobilized in the subsurface as entrapped

pools, as ganglia in soil macropores, or as a residual saturation in soil micropores. As

with most hydrophobic, dense non-aqueous phase liquids, traditional pump and treat

methods are not likely to be very effective. Also, the immobilized toxaphene may serve

as a long-term source of soil and groundwater contamination due to its slow dissolution

in water.

Groundwater contamination due to hydrophobic organic compounds continues to

be a significant problem in the environmental field. As a result, new remediation

techniques including in-situ flushing using cosolvent-water solutions have been

demonstrated successfully in the field (Imhoff et al., 1995; Rao et al., 1997; USEPA,

1999). It has been well-established that when added to water, cosolvents increase the

solubilization of hydrophobic contaminants in water and hence the rate at which the

contaminant can be removed from a contaminated environment (Morris et al., 1988;

Falta, 1988; Li and Andren, 1994). In addition to the environmental field, cosolvent-

enhanced solubilization was also seen in the fields of enhanced oil recovery and









pharmaceutical sciences, where use of smaller molecular weight alcohols has been

reported to be effective (Rubino and Yalkowsky, 1987a; Imhoff et al., 1995; Rao et al.,

1997). Compounds of interest for environmental cosolvent research to date have been

dense non-aqueous phase liquids (DNAPLs) such as trichloroethylene (TCE),

tetrachloroethylene (PCE), polychlorinated biphenyls (PCBs), etc. (Pinal et al., 1990; Li

and Andren, 1994; Chawla et al., 2001). It is not known whether cosolvent technologies

are effective with other compound types, especially pesticides like toxaphene.

The purpose of this research was to investigate how the addition of different

alcohol cosolvents affected the aqueous solubility of toxaphene. In this investigation, a

comparison was conducted between experimentally derived cosolvency powers of

different alcohols and their theoretical values estimated from the literature.














CHAPTER 2
LITERATURE REVIEW

Cosolvents and Enhanced Solubility

One of the most common groundwater contamination problems is the presence of

dense non-aqueous phase liquids (DNAPLs) like trichloroethene (TCE),

tetrachloroethene (PCE) and many pesticides. Due to their wide usage in industrial and

environmental settings, groundwater at these sites is often contaminated. Removal of

these contaminants from groundwater using traditional pump and treat methods, in which

contaminated groundwater is pumped out and treated above ground, is not very efficient

(Jafvert 1996; USEPA, 1999). There are two primary reasons for the ineffectiveness of

pump and treat technologies in removing DNAPLs. Firstly, hydrophobic compounds are

tightly held within the pore space of the soil sediments by capillary forces; and secondly,

their low aqueous solubility results in a slow rate of removal and necessitates elevated

time to achieve remedial objectives (Jafvert 1996; USEPA, 1999).

In-situ flushing using alcohol cosolvents or surfactants has been shown to be a

solution to the problem of low removal efficiencies of DNAPLs (Imhoff et al., 1995; Rao

et al., 1997). Research in this area has shown that cosolvents can promote contaminant

removal in a number of complementary mechanisms. First, by increasing the aqueous

solubility of the contaminant in water, the mass removal per pore volume is improved

and the dissolution process expedited (Banerjee and Yalkowsky, 1988; Pinal et al., 1990;

Li and Andren, 1994; Imhoff et al., 1995). The second mechanism is the reduction of the

interfacial tension between the water and the contaminant, which may result in physical









mobilization ofNAPLs (Brandes and Farley, 1993; Rao et al., 1997). In addition to these

main mechanisms, others such as the swelling of the NAPL phase relative to the aqueous

phase (Brandes and Farley, 1993; Imhoff et al., 1995); and, under certain conditions,

complete miscibility of the aqueous and NAPL phases take place (USEPA, 1999). The

relative importance of these different mechanisms depends on the phase behavior of the

specific system including the water, cosolvent, and NAPL (Falta, 1998). Solubility

enhancements caused by cosolvent addition generally occur because of changes in the

bulk properties of the isotropic solution (Jafvert, 1996). The addition of cosolvents to

water results in a "cosolvent effect" that affects the ideal equilibrium partitioning

relationships. Cosolvents reduce the polarity of the aqueous phase, resulting in reduction

in the aqueous phase activity coefficient that allows higher concentrations of hydrophobic

solutes to solubilize in the aqueous phase (Groves, 1988). As a water-miscible or

partially miscible organic solvent, the cosolvent reduces strong water-water interactions

and thereby reduces the ability of water to squeeze out a nonpolar solute (Li et al., 1999).

Conversely, there are cosolvents such as chloroform that depress the solubility of the

hydrophobic chemicals in water, a polar solvent (Cho et al., 2003).

Ladaa et al. (2001) stated that only hydrophilic compounds that are completely

miscible in water, such as low molecular weight alcohols and ketones, can be used as

cosolvents. In their study that evaluated the cosolvent effects of ethanol, isopropyl

alcohol, and tert-butyl alcohol on aqueous solubility of PCE, all three alcohols were

observed to increase the aqueous solubility of PCE with tert-butyl alcohol performing

better than isopropyl alcohol, which, in turn, performed better than ethanol as a

cosolvent. Cosolvency in this case increased with the increase in carbon number in the









cosolvent. According to Jafvert (1996), short-chained linear alcohols are excellent in

solubilizing small chlorohydrocarbons, whereas larger hydrocarbon cosolvents work best

for larger and more hydrophobic contaminants.

Factors Affecting Cosolvency

Cosolvency is defined as the effect of the addition of one or more completely

water-miscible organic cosolvents on the water solubility of organic compounds (Li and

Yalkowsky, 1998). Cosolvency is a phenomenon that can be applied for many purposes

in various scientific and engineering fields, such as environmental remediation,

pharmaceutical research, etc. (Rubino and Yalkowsky, 1987a; Imhoff et al. 1995).

Cosolvency power is used to quantify cosolvency and it is defined as the ratio of

solute solubility in a specific organic solvent to the solubility of that solute in pure water

as shown below:

S= log (S//Sw) (2-1)

where Sc and S, are the molar solubilities of solute in pure organic cosolvent and in pure

water, respectively (Fu and Luthy, 1986; Li et al., 1998b; Pinal et al., 1990; Lee et al.,

1993). The values of a can be positive, near-zero, or negative, depending on the relative

polarity of water, solute, and cosolvent (Li et al., 1998b). There are two main factors that

affect cosolvency in solution-the water solubility of the cosolvent and the solute

hydrophobicity.

Water miscibility of cosolvent

The power of cosolvency is stronger for more highly water-miscible alcohols.

According to Ladaa et al. (2001), as the carbon chain length of the alcohols increases, and

thus as they become more hydrophobic, their cosolvency power is expected to increase.

Li and Andren (1994) studied the solubility of polychlorinated biphenyls (PCB) in









water/alcohol mixtures and found that for a given PCB congener, the solubility

enhancement increased with increasing carbon number in the water miscible alcohols

used such as methanol, ethanol and IPA.

Also, the cosolvency of completely miscible organic solvents (CMOS) increases

with decreasing solvent polarity. Pinal and co-workers (1990) investigated the

cosolvency of CMOSs-methanol, 2-propanol, acetone, acetonitrite, dioxane, dimethyl

sulfoxide on solubility of various hydrophobic organic chemicals, and these authors

concluded that the lower the polarity of the solvent, the better its ability to solubilize a

hydrophobic solute (Pinal et al., 1990). Rubino and Yalkowsky (1987a) discussed the

variation of cosolvency power with different polarity indices such as dielectric constant,

solubilization parameter, interfacial tension, surface tension and octanol water partition

coefficient. It was concluded that cosolvency power decreased linearly with the increase

in all of these parameters except log (octanol water partition coefficient), in which case

the trend was in reverse order. Overall, as the polarity of the cosolvent increased, the

cosolvency power decreased.

Solute hydrophobicity

It is also evident that solubility enhancement is related to the degree of chlorination

or the hydrophobicity of the organic solutes. The extent of solubility enhancement by the

same alcohol increases as the solute hydrophobicity increases. Li and Andren (1994)

found that using the same alcohol, methanol, the aqueous solubilities of different PCB

congeners were increased to a higher degree in increasing order of the their chlorination.

In a 20% methanol solution, the aqueous solubilities of 4-monochlorobiphenyl, 2, 4, 6-

trichlorobiphenyl and 2, 2, 4, 4', 6, 6'-hexachloroblphenyl were determined to be 3.89,

6.14, and 14.88 times their solubilities in pure water, respectively.









Predicting Cosolvency

In addition to experimental data, there are approximations for estimation of

solubility enhancement in aqueous solutions due to the addition of cosolvents. Various

models are available in literature based on regression analysis from experimental data

(Morris et al, 1988; Li et al, 1998b); however, the most widely used is the log linear

model (Yalkowsky and Roseman, 1981; Imhoff et al., 1995; Rao et al., 1997)

Log linear model

The log linear model, proposed by Yalkowsky and Roseman (1981), estimates the

solubility of a non polar solute in a mixed (cosolvent-water) solvent (Sm) by

ln(Sm) = fln(S) + (1-f) ln(Sw) (2-2)

where f is the cosolvent volume fraction and So and Sw are the solubilities in pure

cosolvent and pure water (Morris et al., 1988). It assumes the absence of specific solute-

solvent interactions and is based upon a linear relationship between the free energy of the

solution and solute surface area. The solute contacts both water and cosolvent, and the

fraction of the solute component is approximately proportional to the volume fraction of

that component. Eq. (2-2) can be rewritten as

log(Sm) = flog(Sc/Sw) + log(Sw) (2-3)

log(Sm) = fo + log(Sw) (2-4)

Plotting log solubility of hydrophobic solute in water and cosolvent mixture vs.

volume fraction of cosolvent used generally results in a straight line, and the slope of this

line is referred to as cosolvency power (a).

Also, there is a correlation between cosolvency power of an organic solvent and the

log octanol water partition coefficient (log Kow) of the solute (Li et al., 1998a; Corseuil et









al., 2004). Cosolvency power has been reported by these authors to correlate linearly

with the log Kow, as given below:

c = M Kow + N (2-5)

For a specified solute/cosolvent/water system, the regression parameters M and N are

specific for the cosolvent and independent of the solutes, and can be viewed as measures

of cosolvent polarity (Rubino and Yalkowsky, 1987a; Li et al., 1998a).

Eq. (2-2) treats water and cosolvent as two distinct entities and neglects the

interaction between them. Sometimes, this approximation cannot hold under conditions

where the cosolvent is present at infinite dilution. In these situations, the solute will on

average be influenced by only one cosolvent molecule at a time, and any solubility

enhancement will be proportional to the number of cosolvent molecules present (Powers

et al., 2001). Work by Banerjee and Yalkowsky (1988), and Cho et al. (2003) focusing

on cosolvency in dilute systems seems to indicate that the magnitude of the solubility

enhancement is linear up to some 10-20% cosolvent fraction. At very low concentrations

of cosolvent, the assumption of non-interaction between the cosolvent and water does not

hold. In dilute solutions, the individual cosolvent molecules will be fully hydrated and,

as a result, will disrupt the water network structure (Grunwald, 1986). If the total volume

disrupted is regarded as the extended hydration shell and if S,* is the average solubility

of the solute within this shell, then the overall solubility Sm of the solute in the water-

cosolvent mixture will be approximated by

Sm = fcVH Sc* + (1- fcVH) Sw ; fcVH < 1 (2-6)

where VH is the ratio of the hydration shell volume to the volume of the cosolvent

(Banerjee and Yalkowsky, 1988).









In dilute solutions, the solute will generally contact only one hydrated cosolvent

molecule at a time, and the degree of solubilization should be a linear rather than a

logarithmic function of cosolvent content (Banerjee and Yalkowsky, 1988). Thus, it is

expected that the log-linear relationship between Sm and f, that applies at high cosolvent

concentrations will become linear at low cosolvent levels due to a change in the

mechanism of solubilization.

UNIFAC model

An alternative approach to modeling the solubilities of hydrophobic organic

compounds in a cosolvent mixture uses a thermodynamic basis to estimate the activity

coefficients of each component in each phase. The activity coefficient of component i, yi,

is a measure of the extent of deviation from the ideal behavior. These activity

coefficients in different phases are then used in a set of equations that equate the

chemical activities of a species between the two phases. A model known as UNIFAC

divides the activity coefficient, y, into a combinatorial part, y7, which reflects the size and

shape of the molecules, and a residual portion yr, which depends on the functional group

interactions.

In y = In yc + In yr (2-7)

The basic assumption of UNIFAC is that a physical property of a fluid is due to the

sum of contributions made by the molecule's functional groups (Li, 2001). The UNIFAC

model, allows the necessary parameters to be estimated from the number and type of

functional groups that comprise the chemical species (Gupte and Danner, 1987; Pinal et

al., 1990; Powers et al., 2001; Li, 2001).

One of the major advantages of the UNIFAC model is that two of the assumptions

made in the log linear model are not necessary because all the possible interactions are









explicitly considered. Furthermore, calculations of y in mixtures with UNIFAC are

possible using only pure component data. One disadvantage, however, is that a number

of interaction parameters of environmental interest are not yet available. In addition,

being a group contribution method, distribution between isomers is not possible with

UNIFAC. For ternary solvent systems where mutual solubility is significant, UNIFAC

can be implemented into available algorithms for constructing phase diagrams. The

composition of each component in each phase as well as the relative amounts of organic

and aqueous phases present can be obtained from the phase diagram. Gupte et al. (1987)

discussed that UNIFAC predictions are not always very accurate, especially for systems

including water and alcohol (Pinal et al., 1990).

Extended log linear equations

Work by Yalkowsky et al. (1985), Rubino and Yalkowsky (1987b), Morris et al.

(1988), and Li and Andren (1994), showed that deviations from the log linear model were

also observed in the case of water and miscible cosolvent mixtures, which are considered

mainly due to nonideality of the solvent mixture. The nonideality of a mixture is

quantitatively measured by the excess free energy of mixing,

AGE= RT (X, In y,) (2-8)

where R is the gas constant, T is the absolute temperature, and Xi is the mole fraction of

component i in the solution. The activity coefficient of component i, yi, is a measure of

the extent of deviation from the ideal behavior.

Pinal et al. (1991) proposed that a term 2.303 (fi log yi), which is the analogue to

(Xi In Yi), be added to the simple log linear model to account for the effect of the

solvent nonideality. Li (2001) further provided an approach to accurately predict









cosolvency by extending the log linear model. Activity coefficients of the system

components are estimated using UNIFAC group contribution method, and the sum of

their logarithms weighted by either mole fractions or volume fractions is added to the

log-linear model. Four such extended forms were given:

Equation I: Log Sm = Log Sw + o f+ log yw + f log(y7 / yw) (2-9)

Equation II: Log Sm = Log Sw + f + log yw + x log(y7 / yw) (2-10)

Equation III: Log Sm= Log Sw + o f+ In yw + f ln(y7 / yw) (2-11)

Equation IV: Log Sm = Log Sw + o f+ In yw + x ln(y7 / y) (2-12)

where Sm and Sw are the molar solubilities of hydrophobic solute in mixed solvent and

pure water, respectively. The constants yw and y are activity coefficients of water and

cosolvent in a solute-free mixed solvent, respectively. The volume fraction of the

cosolvent is labeled f and x is the mole fraction of the cosolvent. The last two terms in

the above equations are the infinite dilution activity coefficient of a solute in a solvent

mixture expressed as a power series in the volume fractions of solvent components.

Toxaphene

Toxaphene is identified by CAS# 8001-35-2 and by its United Nations Department

of Transportation number, UN# 2761 (USEPA, 1998). Because of its toxicity,

persistence and heavy use, toxaphene is one of the "dirty dozen," 12 chlorinated

compounds designated for international action by the United Nations Environmental

Program (ATSDR, 1996). In the United States, about 85% of the toxaphene was used for

the control of cotton insect pests, 15% was used to control insect pests on livestock,

poultry, and a few field crops other than cotton (IARC, 1979). Toxaphene solutions were

often mixed with other pesticides partly because toxaphene solutions appear to help

solubilize other insecticides with low water solubility. Toxaphene was frequently applied









with methyl or ethyl parathion and lindane (WHO 1974; IARC 1979; ATSDR, 1996).

Table 2-1 gives the physical/chemical properties of toxaphene (ATSDR, 1996).

Table 2-1. Chemical/physical properties of toxaphene
Property Value or Information
Chemical name(s) Toxaphene, camphechlor; chlorinated camphene
Chemical formula C0oH10Cls (average; includes components with 6 to
10 chlorines)
Molecular weight 414 (average)
CAS number 8001-35-2
USEPA hazardous waste code P123
Trade names Agricide Maggot Killer, Alltox, Camphofene,
Huilex, Geniphene, Hercules 3956, Hercules
Toxaphene, Motto, Penphene, Phenicide, Phenatox,
Strobane-T, Synthetic 3956, Toxakil
Color/form/odor Yellow waxy solid with mild turpentine odor
Melting point 65-90 C
Octanol-water partition 3.3 (Log Kow)
coefficient (Kow)
Density/specific gravity 1.65 at 25 C
Solubility in water 3 mg/L


Composition of Toxaphene

Toxaphene is a mixture of chlorinated camphenes that occurs as a waxy yellow or

amber solid, with a pleasant odor (Sergeant and Onuska, 1989). It consists of 600 hexa-

to decachlorinated bornanes and bornenes. Toxaphene, also known as chlorinated

camphene, is a complex mixture of polychlorobicyclic terpenes, with chlorinated

camphenes predominating (67-69% chlorine) (Food and Agricultural Organization

[FAO], World Health Organization [WHO], 1968). The source ofterpene and the degree

of chlorination outside the 67-69 percent range alter the insecticidal activity. The









composition of toxaphene is very complex, consisting of over 32,000 possible congeners,

of these, only a limited number of congeners have been individually isolated and

characterized. The average empirical formula is CloHioCls (ATSDR, 1996). A double

bond is present in some congeners but absent in others and the level of chlorination

ranges between 6 and 10. Ten different carbon atoms are present which can be

substituted with 1 or 2 chlorines, each leading to a very large number of isomers, many of

which are chiral. The basic structure of components in toxaphene is as shown in figure 2-

1 (Buser and Muller, 1994).










Camphene Polychlorobornane Polychlorobornene
Figure 2-1. Basic structure of components of toxaphene

Toxaphene was first synthesized in 1947 by the Hercules Chemical Co. and was

patented in 1951 (James and Hites, 2002). The mixture was produced in three steps: (a)

the extraction of a-pinene from pine stumps, (b) the isomerization of this compound to

camphene, and (c) the photochlorination of camphene to produce toxaphene (Rumker et

al., 1975). The toxaphene mixtures are prepared commercially as dusts, sprays, and

wettable powders and are used alone or in combination with other pesticides for use on

cotton and food crops. Toxaphene is now most often produced by the controlled

chlorination of camphene (2,2-dimethyl-3-methylene-bicyclo[2.2.1 ]heptane) under UV

light (James and Hites, 2002).









Toxaphene in Water

Deposition of airborne toxaphene and/or its direct application to water bodies for

the elimination of undesirable species has resulted in the detection of significant

quantities in surface waters (ATSDR, 1996). Due to the low water solubility (3 mg/L), a

majority of the toxaphene molecules strongly bind to particles and is deposited on

sediments; however, there is a presence in groundwater as a result of normal agricultural

use. Toxaphene enters surface waters through runoff from rain, by direct application to

lakes as a pesticide, by wastewater release from manufacturing facilities, and through

activities related to disposal of waste pesticides (James and Hites, 2002). Toxaphene also

enters water bodies when it is transported with soil particles.

In water, toxaphene appears to be resistant to all forms of degradation. It is not

known to undergo photolysis or photo-oxidation. A hydrolytic half-life of 10 years was

estimated for water at pH 5 to 8 (ATSDR, 1996). The ability to persist in the

environment with little or extremely slow decay, its ability to bioaccumulate

(Bioconcentration factor of the order of 10,000) and the general toxicity danger to

environment and humans make toxaphene a pollutant of concern (ATSDR, 1996).

Toxaphene has been detected at hazardous waste sites in surface water,

groundwater, and leachates (ATSDR, 1996). Toxaphene was detected at a maximum

concentration of 17 ppb in surface water samples taken from 2 of 9 disposal ponds at a

Super-fund site (USEPA 1986). In a study of the chemical composition of leachates

within existing landfills, toxaphene was not detected in any of the municipal landfill

leachates examined; however, the mixture was detected in industrial landfill leachates at

a concentration of 10 ppb. In a review of groundwater monitoring data collected in 1981-

1984 from more than 500 wells at 334 hazardous waste disposal sites (RCRA and






15


CERCLA sites) located in all 10 USEPA regions and 42 states, Plumb (1987) reported

that toxaphene was detected at 0.2% frequency at the 178 CERCLA sites examined and

at 1.1% frequency at the 156 RCRA sites examined. Toxaphene has also been detected

in surface water samples from 12 of 58 NPL sites, in groundwater samples from 20 of 58

NPL sites and in leachate samples from 1 of 58 NPL sites where toxaphene has been

detected in some environmental media; however, concentrations were not reported

(ATSDR 1996).














CHAPTER 3
MATERIALS AND METHODS

Enhanced solubilization of toxaphene by addition of alcohol cosolvents in the water

was evaluated by performing batch experiments according to Pinal et al. (1990) but

changed for toxaphene according to analytical methods for toxaphene using USEPA

method 8081B, which suggests the total area approach for toxaphene analysis using a gas

chromatograph fitted with an electron capture detector (GC-ECD).

Materials

Toxaphene was obtained from Chem Service, West Chester, PA as a mix of

isomers and was used as received for batch tests. For GC-ECD analytical calibration

curve, toxaphene was obtained from AccuStandard with a concentration of 1000-ppm in

hexane matrix. Methanol, ethanol, and IPA were chosen as cosolvents in this research.

They were used as received from Fisher-Scientific. Alcohols with higher carbon

numbers were found to be only partially miscible in water and hence were not used. The

following criteria were used for the selection of cosolvents for this research and were

similar to those considered by Chawla et al. (2001) a) non-toxic, b) biodegradable, c)

completely miscible with water, d) relatively inexpensive; and e) commonly available.

Physical/chemical properties of the cosolvents, methanol, ethanol and IPA are provided

in Table 3-1 (Chawla et al., 2001).









Table 3-1. Cosolvent properties
Property Methanol Ethanol IPA
Boiling point (C) 65 79 80
Vapor pressure at 20 C (mm Hg) 127 40 33
Specific gravity at 20 C 0.791 0.79 0.786
Solubility in water 100% 100% 100%
Carcinogenicity No No No
Biodegradability in soil Readily Readily Moderately
Biodegradability in water Readily Readily Moderately
Half life in soil (days) 1-10 N/A 1-10
Environmental toxicity Slightly toxic Not toxic Not toxic
LD5o (mg/kg) 5628 7060 5045
Bioaccumulation No No No
Price ($/200L) 672.50 917.80 868.15
Dipole moment (debye) 1.70 1.69 1.58
(Lide, 1996)

Experimental Methods

Cosolvent solutions, over a wide range of concentrations (10%, 20%, 30%, 40%,

50%, 60%, and 75% alcohol by volume), were prepared by adding methanol/ethanol/IPA

separately in water in 50 ml flasks. Samples were prepared in 5 ml glass vials fitted with

a Teflon-coated, septum-lined screw cap to prevent potential volatilization. Each vial

was weighed empty; and 5 mg of toxaphene was then added to each vial and the vials

were weighed again. The vials were subsequently filled with cosolvent solutions

allowing no headspace and reweighed. All samples were prepared in triplicate. Samples

were then placed on a rotator (40% revolution, 24 rpm) for about a 24-hr equilibrium

period. Tests were conducted for equilibrium period of 1 week, results from which did









not show a significant difference from those of the equilibrium period of 24 hrs; hence it

was assumed that the equilibrium was reached.

A known volume (2 ml for 0%, 10% and 20%, 1 ml for 30% and 40%, and 0.5 ml

for 50%, 60% and 75% cosolvent concentration) of these solutions was transferred to

other 5 ml glass vials for volatilization. After approximately 48 hrs, a known volume of

hexane was added to the vials, which were then put on the rotator. After about 24 hrs,

two layers could distinctly be seen in the vials. Samples from the upper layer containing

hexane and toxaphene were used for GC-ECD analysis.

Analytical Methods for Toxaphene

GC-ECD is the most frequently used analytical method for characterization and

quantification of toxaphene in air, drinking water, fish, and other environmental samples.

Analysis of the sample includes extraction in organic solvent; a Florisil silica, gel

permeation, or TLC clean-up step; and detection by GC. It is also the standardized

method used by USEPA (method 8081B) for determining toxaphene in water and soil

samples. A typical gas chromatogram contains a series of hills and valleys with three

main peaks (USEPA, 1998; Clark et al., In press). While toxaphene contains a large

number of compounds that will produce well-resolved peaks in a GC-ECD

chromatogram, it also contains many other components that are not chromatographically

resolved. Although, the resolved peaks are important for the identification of the

mixture, the area of the unresolved complex mixture contributes a significant portion of

the area of the total response (USEPA, 1998). For the above reason, the area under the

curve is used for the quantitation of total toxaphene (USEPA, 1998; Clark et al., In

press). Detection limits of 0.086 tg/L of water and 5.7 pg/kg of soil were reported for

toxaphene (ATSDR, 1996).






19


For this research, GC-17A Shimadzu equipped with DB-30 column and a 63Ni

electron capture detector was used for analysis of samples. The program was set for

calculating constant velocity and total area approach was used for measuring the

toxaphene present in the hexane extracted aqueous phase. Concentration of toxaphene in

each solution was determined from an 8-point calibration curve, ranging from 0.2-50 ppm

of toxaphene concentration, developed experimentally using known standard toxaphene

solution. Samples were diluted to bring the solute concentrations within this range.















CHAPTER 4
RESULTS AND DISCUSSION

Toxaphene solubility in binary water-cosolvent solutions was determined

experimentally by performing batch experiments. In addition, the cosolvency powers for

toxaphene solubilized in different alcohols/water systems were determined using the

experimental results from the batch tests and compared with theoretical values predicted

from the literature.

Experimental Results

Toxaphene concentrations in the cosolvent-water mixture were obtained using GC-

ECD methods as previously described. Solubility of toxaphene was plotted as a function

of the volume fraction of the cosolvents (Figures 4-1 4-3):



Methanol as cosolvent

4





Slope = 3.46
R2 = 0.99
1-1


0
0 0.2 0.4 0.6 0.8 1
Volume fraction cosolvent

Figure 4-1. Log solubility of toxaphene in water-methanol system as a function of
cosolvent volume fraction












Ethanol as cosolvent


Slope = 3.60
R2 = 0.98


0 0.2 0.4 0.6 0.8 1
Volume fraction cosolvent

Figure 4-2. Log solubility of toxaphene in water-ethanol system as a function of
cosolvent volume fraction


IPA as cosolvent


Slope = 4.30
R2 = 0.98


0 0.2 0.4 0.6 0.8 1
Volume fraction cosolvent

Figure 4-3. Log solubility of toxaphene in water-IPA system as a function of cosolvent
volume fraction

In Figures 4-1 4-3, each datum point represents the logarithm of single batch test

solubility result and each error bar represents a fixed value of 0.1. These log-linear plots

show that the aqueous solubility of toxaphene increases with an increase in volume









fraction (f) of cosolvent in the solution. This trend is similar to the previous works on

solubility ofPCBs, PCE and other chlorinated compounds (Yalkowsky et al., 1985; Pinal

et al., 1990; Li and Andren, 1994; Chawla et al., 2001). Previously mentioned, the slopes

of these plots (Figures 4-1 4-3) represent the cosolvency powers of the cosolvents,

which is the parameter used for evaluation of the effectiveness of the cosolvent in

enhancing solubilization of toxaphene in water (Pinal et al., 1990). Therefore, solvents

with higher cosolvency power values solubilize more contaminant for equivalent amount

of volume fraction in binary solution.

It was observed from plots (Figures 4-1 4-3), that they display two distinctive

regions, divided at a volume fraction of 0.2. More specifically, slope of the line f< 0.2 is

usually less than the slope of the line f > 0.2. For clarification, solubility values at each

fraction of cosolvent, f, were averaged and then plotted as shown in Figure 4-4, which

clearly shows the two parts of the curve for each cosolvent, similar to observations have

been made by Banerjee and Yalkowsky (1988), Morris et al. (1988), Pinal et al. (1990)

and Li and Andren (1994). Banerjee and Yalkowsky (1988) attributed this to the

hydration of cosolvent molecules in dilute solutions, and interaction between hydrated

shells of the cosolvent molecules.










Log solubility of toxpahene in different cosolvents

4


S---- Methanol
2 --Ethanol
SL--IPA


0
0 0.2 0.4 0.6 0.8
Volume fraction cosolvent

Figure 4-4. Log solubility of toxaphene in different cosolvents

Cosolvency powers of toxaphene in binary solutions containing water for methanol,

ethanol and IPA were determined and listed in Table 4-1.

Table 4-1. Cosolvency power of toxaphene in water alcohol mixtures
Fraction Cosolvency 2 Overall cosolvency
Cosolvent R R
range power power

0 0.2 2.71 0.94
Methanol 3.46 0.99
0.2 0.75 3.63 0.99

0 -0.2 4.00 0.80
Ethanol 3.60 0.98
0.2 0.75 3.79 0.98

0 -0.2 2.97 0.98
IPA 4.30 0.98
0.2-0.75 4.37 0.95


Results indicate that toxaphene cosolvency was directly related to the number of

carbons in the cosolvent utilized. As the number of carbon atoms in the cosolvent

increases, so did the toxaphene solubility. A similar trend was observed by Ladaa et al.

(2001) and, Li and Andren (1994). The following trend was observed for this research:

IPA > ethanol > methanol









It was found that the cosolvency of toxaphene in the aqueous solution increased

with decreasing solvent polarity in agreement with Pinal et al. (1990). Methanol was

most polar (highest dipole moment; Table 3-1) among the three alcohols used and was

found to be least effective in solubilization of toxaphene. It has a smaller non-polar alkyl

group than ethanol and IPA, and, hence, its ability to reduce the polarity of the whole

solution is less than other two alcohols, as a result, its cosolvency on the solubility of the

toxaphene was the least.

Also, it was found that for methanol fractions less than 20%, the relationship

between solubility and volume fraction of methanol is linear. The similar observation for

methanol was also seen by Banerjee and Yalkowsky (1988), and Li (2001). These

differences are attributed to the hydration of the cosolvent molecules at low

concentrations (Banerjee and Yalkowsky, 1988). This trend was only seen for methanol,

perhaps because methanol has a smaller molecular weight and size, it may become

integrated into water structure better than other two cosolvents, which tend to perturb the

water network (Grunwald, 1986; Rubino and Yalkowsky, 1987b).


Linearity between solubility and
volume fraction of methanol



12 -



0 ,

0 0.1 0.2
Volume fraction cosolvent

Figure 4-5. Linearity between toxaphene solubility and 0-0.2 volume fraction region of
methanol









Theoretical Estimations

Cosolvency power can also be estimated using its relationship with log (octanol

water partition coefficient) using the relationship:

o = a log P + b (4-1)

Where P is the octanol/water partition coefficient of the solute and a, b are the regression

parameters (slope and y-intercept) obtained from the a vs. log P curve (Morris et al.,

1988). For toxaphene, the value of log P of 3.3 was used for these estimations (ATSDR,

1996). Estimated values of cosolvency power for methanol, ethanol and IPA are as listed

in Table 4-2.

Table 4-2. Estimation of cosolvency power for methanol, ethanol and IPA
Cosolvent Cosolvency power
Cosolvent
Morris et al., 1988 Li et al., 1998b
Methanol 3.31 3.16-3.43
Ethanol 3.62 3.33 3.54
IPA 3.57 2.75 3.57


Based on cosolvency power and using the log linear model, the solubility of

toxaphene can also be estimated in the presence of different volume fractions of different

cosolvents. Toxaphene solubility in different water-cosolvent systems were determined

theoretically using the log linear model (Equation 2-4) by substituting the value of

toxaphene solubility in pure water (3 ppm, ATSDR 1996) and cosolvency power values

(Table 4-2). Equation 2-2b takes the final form for different cosolvents as shown below

(Equations 4-2 4-4):

Methanol: Log(Sm)est = 3.31 *f+ log (3) (4-2)

Ethanol: Log(Sm)est = 3.62*f+ log (3) (4-3)

IPA: Log(Sm)est = 3.57*f+ log (3) (4-4)









Comparison of Experimental Values with Estimations

Values of cosolvency powers for methanol, ethanol and IPA were estimated from

data available in literature. These estimated values of cosolvency powers were plotted

and compared with experimental results from solubility batch tests. The percentage

difference between estimated values and experimental values were also calculated using

the following relationship,

% difference= exp)-est))*100 (4-5)
[ G(exp) J

Table 4-3. Comparison of experimental cosolvency power with estimated
Cosolvent Cosolvency power
Cosolvent
Estimated G(est) Experimental G(exp) % Difference
Methanol 3.31 3.46 4.34
Ethanol 3.62 3.60 -0.56
IPA 3.57 4.30 16.98


There was a discrepancy found in estimated and experimental cosolvency powers

of IPA, which may be due to the branched nature of the IPA molecule compared to the

other straight-chain alcohols. Cho et al. (2002) studied the effect of molecular structures

of surfactants on the solubility enhancement of polycyclic aromatic compounds and

found that surfactants with a bulky polar heads were somewhat less efficient for solute

solubilization. Overall, research in this field seems to be limited and requires further

exploration. For the straight chain alcohols, methanol and ethanol, theoretical and

experimental values of cosolvency power, are within a range of 95-100%.

Toxaphene solubility obtained theoretically using equations 4-2 4-4 were

compared with experimental values as shown in Table 4-4, where log(Sm)exp and

log(Sm)est are the logarithms of toxaphene solubility in ppm in mixed water-cosolvent









system, obtained experimentally and estimated from log linear model. Each (Sm)exp is the

mean of at least 2 experimental values of solubility. Diff. is the difference between

log(Sm)exp and log(Sm)est.

Table 4-4. Comparison of experimental toxaphene solubility with estimations in different
cosolvents
Methanol Ethanol IPA
f log(Sm)exp log(Sm)est Diff. Log(SLog(S) og(Sm)est Diff. log(Sm)exp Log(Sm)est Diff.
0 0.48 0.48 0.00 0.46 0.48 -0.01 0.52 0.48 0.04
0.1 0.83 0.81 0.02 1.16 0.84 0.32 0.82 0.83 -0.01
0.2 0.99 1.14 -0.15 1.27 1.20 0.06 1.11 1.19 -0.08
0.3 1.43 1.47 -0.04 1.59 1.56 0.02 1.67 1.55 0.13
0.4 1.72 1.80 -0.08 1.86 1.93 -0.06 2.34 1.91 0.43
0.5 2.17 2.13 0.04 2.48 2.29 0.19 2.78 2.26 0.52
0.6 2.59 2.46 0.12 2.75 2.65 0.10 3.17 2.62 0.55
0.75 3.01 2.96 0.05 3.30 3.19 0.11 3.45 3.15 0.30
Average absolute difference 0.06 0.11 0.26


Results in Table 4-4 show that the solubility of toxaphene was increased from 3

ppm in pure water to 1000-2000 ppm for high concentrations of cosolvents, varying with

the cosolvent. Average absolute difference was calculated for each cosolvent. These

differences or deviations from log linear model were generally negative for dilute

solutions and positive for higher volume fractions of cosolvent, similar to results reported

by Rubino and Yalkowsky (1987b) and Li (2001). To further quantify these deviations,

log linear model was modified as with the equations offered by Li (2001). Extended log

linear equations described in Chapter 2 were plotted and compared with experimental

results, as shown in the Figures 4-6 4-8.












Best fit for methanol


Experimental
-- Log linear
- Extended log linear I
....... Extended log linear II
----- Extended log linear III
----- Extended log linear IV


0.2 0.4 0.6 0.8


Volume fraction cosolvent


Figure 4-6. Comparison of log linear model with experimental values for methanol



Best fit for ethanol


Experimental
-- Log linear
- Extended log linear I
-...... Extended log linear II
----- Extended log linear III
----- Extended log linear IV


0.0 0.2 0.4 0.6 0.8 1.0

Volume fraction cosolvent


Figure 4-7. Comparison of log linear model with experimental values for ethanol


1.5


1.0


0.5


0.0


3.0


2.5


2.0
E

S1.5


1.0


0.5

0.0











Best fit for IPA

3.5

3.0 -

2.5 -. Experimental
S- Log linear
S2.0 "
S2/ / -Extended log linear I
S1.5 -./ -.......-- Extended log linear II
Sl *' -.- Extended log linear III
1^ -.. -. Extended log linear IV



0.0
0.0 0.2 0.4 0.6 0.8 1.0
Volume fraction cosolvent


Figure 4-8. Comparison of log linear model with experimental values for IPA

Equations 2-9 2-12 were used and the mole fraction, x, of the cosolvent was

calculated on the basis of solute-free solvent mixture. Activity coefficients for different

mole fractions and different cosolvents were taken from Li (2001). Average absolute

differences in estimations from different extended log linear equations and experimental

results were calculated in a similar fashion as done previously for log linear model and

experimental results. For methanol, none of the extended equations generate improved

solubility estimates than the original log linear model. For ethanol, extended log linear

equation II gives the best results, and the lowest average absolute difference. For IPA,

however, the trend has a jump from log linear for the low cosolvent fractions (f <0.3) to

extended log linear equation III.

These extended log linear equations give estimated solubility in mixed solvent

higher than log linear model because of the additional terms in the equations which take









nonideality of solvent mixture into consideration. Therefore, the extended log linear

model did not improve the negative deviations from log linear model, however the

positive deviations were improved in case of methanol, ethanol, and greatly in case of

IPA.

Overall, toxaphene solubility in water increased significantly with addition of

cosolvent. The log linear model can be used for predicting the cosolvency power and,

therefore, the solubility oftoxaphene in other water-cosolvent solutions as well. Results

from this research have promising applications in the field of environmental remediation

using in-situ flushing and studies of fate and transport of pollutants.

The results from this research has a limitation to field application, Since cosolvency

of alcohols also depends on the solute hydrophobicity (Yalkowsky et al., 1985; Li and

Andren, 1994), toxaphene in the field sites can have a different chlorine atom number and

hence different hydrophobicity levels than that were explored in the present research.

Pilot studies could be performed using samples from the site under consideration.

Future Work

As it was concluded from this research that toxaphene cosolvency increases with

increase in carbon numbers in the cosolvent, higher molecular weight alcohols (e.g.,

butanol, pentanol etc.) should be used for further research in order to quantify the

deviations from log linear model. Effect of branched and straight chain alcohols on

aqueous solubility of toxaphene can also be evaluated.














CHAPTER 5
CONCLUSIONS

The purpose of this research was to evaluate the effectiveness of alcohol cosolvents

in enhancing the solubility of toxaphene in water. Batch experiments were conducted for

toxaphene solubility in binary water-cosolvent solutions, including methanol, ethanol and

IPA. It was concluded that alcohol cosolvents do indeed increase the solubility of

toxaphene in water, sometimes on the order of hundred-fold increase. Plots of toxaphene

solubility in mixed solvent vs. volume fraction of cosolvent in the mixed solvent showed

a log linear relationship. The cosolvency power was determined and found to be within

the range of 83-100% of the values estimated from literature. Methanol showed linearity

for the above-mentioned plot for cosolvent fractions less than 20% which was attributed

to its lower molecular weight.

Deviations from the log linear model were observed, similar to what has been seen

in the literature as well. Approaches from literature were used to modify the log linear

model to more accurately predict the toxaphene cosolvency. It was found that for

methanol none of the approaches used gave less average absolute difference than the log

linear. For ethanol, one of the approaches based on the nonideality of the solvent mixture

gave better match with experimental results. For IPA, the experimental values moved

from the log linear to modified log linear.

Comparing the effect of different alcohols, it was found that with increasing carbon

number in the cosolvent, the solubility enhancement was increased. IPA is more polar

than ethanol, which in turn is more polar than methanol. The performance of the






32


cosolvents in increasing aqueous solubility of toxaphene was in reverse order of their

polarity.

Overall, this research proved the potential of alcohol cosolvents in increasing

aqueous solubility of toxaphene. Prospective applications of this research are in the field

of environmental remediation of hazardous sites or aquifers contaminated with toxaphene

by in-situ flushing.















LIST OF REFERENCES


Agency for Toxic Substances and Disease Registry (ATSDR), 1996. Toxicological
Profile for Toxaphene (Update), U.S. Department of Health and Human Services,
Public Health Service, August, Atlanta, GA.

Banerjee S, Yalkowsky S H, 1988. Cosolvent-induced Solubilization of Hydrophobic
Compounds into Water, Analytical Chemistry, 60, 2153-2155.

Brandes D, Farley K, 1993. Importance of Phase Behavior on the Removal of Residual
DNAPLs from Porous Media by Alcohol Flooding. Water Environmental
Research, 65, 896-878.

Chawla R C, Doura K F, McKay D, 2001. Effect of Alcohol Cosolvents on the Aqueous
Solubility of Trichloroethylene. Proceedings of the 2001 Conference on
Environmental Research, Kansas State University, Manhattan, Kansas, 52-66.

Cho J, Annable M D, Rao P S C, 2003. Residual Alcohol Influence on NAPL Saturation
Estimates based on Partition Tracers. Environmental Science and Technology, 37,
1639-1644.

Clark II C J, Chen X, Babu S, In Press. Degradation of Toxaphene by Zero-Valent Iron
and Bimetallic Substrates. Journal of Environmental Engineering.

Corseuil H X, Kaipper B I A, Fernandes M, 2004. Cosolvency Effect in Subsurface
Systems Contaminated with Petroleum Hydrocarbons and Ethanol. Water
Research, 38, 1449-1456.

Falta RW, 1998. Using Phase Diagrams to Predict the Performance of Cosolvent Floods
for NAPL Remediation, Ground Water Monitoring and Remediation, 18 (3), 94-
102.

Food and Agricultural Organization (FAO) of the United Nations, World Health
Organization (WHO), 1968. Evaluations of Some Pesticide Residues in Food, The
Monographs, Joint Meeting on Pesticide Residues, International Programme on
Chemical Safety, Geneva.

Fu J K, Luthy R G, 1986. Aromatic Compound Solubility in Solvent/Water Mixtures.
Journal of Environmental Engineering, 112 (2), 328-345.

Glassmeyer S T, Shanks K E, Hites R A, 1999. Automated Toxaphene Quantitation by
GC/MS. Analytical Chemistry, 71, 1448-1453.









Groves F R, 1988. Effects of Cosolvents on the Solubility of Hydrocarbons in Water.
Environmental Science and Technology, 22 (3), 282-286.

Grunwald E, 1986. Thermodynamic Properties of Nonpolar Solutes in Water and the
Structure of Hydrophobic Hydration Shells. Journal of American Chemical Society,
108, 5726-5731.

Gupte P A, Danner R P, 1987. Prediction of Liquid-Liquid Equilibria with UNIFAC: a
Critical Evaluation. Industrial & Engineering Chemistry Research, 26, 2036-2042.

International Agency for Research on Cancer (IARC), 1979. Second Annual Report on
Carcinogens, 20, Geneva.

ImhoffP T, Glyzer S, McBride J, Vancho L, Okuda I, Miller T, 1995. Cosolvent-
Enhanced Remediation of Residual Non-Aqueous Phase Liquids: Experimental
Investigation. Environmental Science and Technology, 29, 1966-1975.

Jafvert C T, 1996. Technology Evaluation Report: Surfactants/Cosolvents. TE-96-02,
Ground-Water Remediation Technologies Analysis Center, Pittsburgh, PA.

James R R and Hites R A, 2002. Atmospheric Transport of Toxaphene from the Southern
United States to the Great Lakes Region. Environmental Science and Technology,
36 (16), 3474-3481.

Ladaa T I, Lee C M, Coates J T, Falta R W Jr, 2001. Cosolvent Effects of Alcohols on
the Henry's Law Constant and Aqueous Solubility of Tetrachloroethylene (PCE).
Chemosphere, 44, 1137-1143.

Lee L S, Bellin C A, Pinal R, Rao P S C, 1993. Cosolvent Effects of Sorption of Organic
Acids by Soils from Mixed Solvents. Environmental Science and Technology, 27,
165-171.

Li A, 2001. Predicting cosolvency. 3. Evaluation of Extended Log Linear Model.
Industrial & Engineering Chemistry Research. 40, 5029-5035.

Li A, Andren A W, 1994. Solubility of Polychlorinated Biphenyls in Water/Alcohol
Mixtures. 1. Experimental data. Environmental Science and Technology, 28 (1),
47-52.

Li A, Yalkowsky S H, 1998a. Predicting Cosolvency. 1. Solubility Ratio and Solute Log
Kow. Industrial & Engineering Chemistry Research. 37, 4470-4475.

Li A, Yalkowsky S H, 1998b. Predicting Cosolvency. 2. Correlation with Solvent
Physicochemical Properties. Industrial & Engineering Chemistry Research. 37,
4476-4480.









Li P, Zhao L, Yalkowsky S H, 1999. Combined Effect of Cosolvent and Cyclodextrin on
Solubilization of Non Polar Drugs. Journal of Pharmaceutical Sciences, 88 (11),
1107-1111.

Lide D R, 1996. CRC Handbook of Chemistry and Physics, 76th Ed, 1995-1996. CRC
Press, Boca Raton, Fl.

Morris K R, Abramowitz R, Pinal R, Davis P, Yalkowsky S H, 1988. Solubility of
Aromatic Pollutants in Mixed Solvents. Chemosphere, 17, 285-298.

Pinal R, Rao P S C, Lee L S, Cline P V, 1990. Cosolvency of Partially Miscible Organic
Solvents on the Solubility of Hydrophobic Organic Chemicals. Environmental
Science and Technology, 24(5), 639-647.

Pinal R, Lee S L, Rao P S C, 1991. Prediction of the Solubility of Hydrophobic
Compounds in Nonideal Solvent Mixtures, Chemosphere, 22, 939-951.

Plumb R H, 1987. A Comparison of Ground Water Monitoring Data from CERCLA and
RCRA Sites. Ground Water Monitoring Review, 7, 94-100.

Powers S E, Hunt C S, Heermann S E, Corseuil H X, Rice D, Alvarez P J J, 2001. The
Transport and Fate of Ethanol and BTEX in Groundwater Contaminated by
Gasohol. Critical Review in Environmental Science and Technology, 31 (1), 79-
123.

Rao P S C, Annable M D, Sillan R K, Dai D, Hatfield K, Graham W D, Wood A L,
Enfield C G, 1997. Field-Scale Evaluation of In Situ Cosolvent Flushing for
Enhanced Aquifer Remediation. Water Resources Research, 33 (12), 2673-2686.

Rubino J T, Yalkowsky S H, 1987a. Cosolvency and Cosolvent Polarity. Pharmaceutical
Research, 4 (3), 220-230.

Rubino J T, Yalkowsky S H, 1987b. Cosolvency and Deviations from Log Linear
Solubilization. Pharmaceutical Research, 4 (3), 231-236.

Rumker V, Lawless W, Neiners A F, Lawrence K A, Kelso G C, Horaz F, 1975. A Case
Study of the Efficiency of the Use of Pesticides on Agriculture. USEPA 540/9-75-
025, Washington, DC.

Sergeant D B, Onuska F, 1989. Analysis of Trace Organics in the Aquatic Environment.
CRC Press, Boca Raton, FL, 69-118.

United States Environmental Protection Agency (USEPA), 1986. Superfund Record of
Decision (USEPA region 4) Gallaway Ponds Site. USEPA/ROD/R04-X6/013,
Gallaway, TN.






36


United States Environmental Protection Agency (USEPA), 1998. Method 8081B:
Organochlorine Pesticides by Gas Chromatography. Test Methods for Evaluating
Solid Waste, Physical/Chemical Methods. Revision 2, Washington, DC.

United States Environmental Protection Agency (USEPA), 1999. In Situ Enhanced
Source Removal. Project Completion Report. USEPA/600/C-99/002, Ada, OK.

Yalkowsky S H, 1985. Solubility of Organic Solutes in Mixed Aqueous Solvent. Project
Completion Report, USEPA CR811852-01-0, Ada, OK

Yalkowsky S H, Roseman T J, 1981. Techniques of Solubilization of Drugs. Marcel
Dekker, New York, 91-134.















BIOGRAPHICAL SKETCH

Padma Paan was born in 1980 in Dhamnod, Madhya Pradesh, India. She did her

undergraduate studies in civil engineering and received a Bachelor of Technology degree

from the Indian Institute of Technology (IIT) Bombay, India, in 2003. In the spring of

2004, she joined the University of Florida for a Master of Science degree in the

Department of Civil and Coastal Engineering under the tutelage of Dr. Clayton J. Clark

II.