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Group Title: Circular
Title: Water quality sampling and analysis instruments and procedures
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 Material Information
Title: Water quality sampling and analysis instruments and procedures
Series Title: Circular
Physical Description: 10 p. : ill. ; 28 cm.
Language: English
Creator: Taylor, L. A ( Laurene A )
Izuno, Forrest T
Bottcher, A. B
Florida Cooperative Extension Service
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1992
 Subjects
Subject: Agricultural pollution -- Florida   ( lcsh )
Water quality -- Measurement   ( lcsh )
Water -- Pollution -- Measurement   ( lcsh )
Water quality management -- Equipment and supplies   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 10).
Statement of Responsibility: L.A. Taylor, F.T. Izuno, and A.B. Bottcher.
General Note: Cover title.
General Note: "October 1992."
 Record Information
Bibliographic ID: UF00014457
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltqf - AAA6900
ltuf - AJK7665
oclc - 27193866
alephbibnum - 001784290

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October 1992
October 1992


Circular 1040


Water Quality Sampling and Analysis
Instruments and Procedures

L. A. Taylor, F. T. Izuno, and A. B. Bottcher


























Florida Cooperative Extension Service
Institute of Food and Agricultural Sciences
University of Florida
John T. Woeste, Dean
























*Trade names are mentioned with the understanding that no discrimination is intended nor endorse-
ment implied by the authors or the Institute of Food and Agricultural Sciences.


L.A. Taylor is a Scientific Research Manager and F.T. Izuno is an Associate Professor and Water Management Specialist at the
Everglades Research and Education Center; A.B. Bottcher is a Professor and Water Resource and Non-Point Pollution Specialist in
the Agricultural Engineering Department, Gainesville; Institute of Food and Agricultural Sciences, University of Florida.







Introduction
A water sample can be analyzed for numerous
chemical properties. This publication will be
limited to a discussion of pH, electrical
conductivity, turbidity, hardness, nitrogen (N) and
phosphorus (P), with the emphasis being on
nitrogen and phosphorus. Total-N and Total-P
measurements account for all nitrogen and
phosphorus, respectively, in organic and inorganic
forms, measurable using standard chemical
analysis procedures.

Nitrogen is an indispensable part of the life
cycle. However, even though plants, animals and
most micro-organisms require some form of
combined nitrogen for growth and reproduction,
concentrations above certain levels can present
problems. Total-N is the sum of Total Kjeldahl
Nitrogen (TKN) (see Izuno, Davis, and Bottcher,
1991 for details) and nitrate (NO 3). Total
Dissolved Kjeldahl Nitrogen (TDKN) is the fraction
of TKN that passes through a 0.45 Vpm filter.
Ammonium (NH +) is another nitrogen parameter
commonly measured and reported. Inorganic
nitrogen is normally found in soil water as
ammonia (NH3), nitrate, and nitrite (NO ).

Ammonia, a product of microbiological decay of
plant and animal protein, is used in commercial
fertilizers. Its excessive presence in raw surface
waters usually indicates domestic or agricultural
pollution. Above certain levels it is toxic to fish.
Excessive amounts of nitrate or nitrite in water can
cause infant death and adult illness, and produce
spontaneous abortion of cows. Fairly low levels of
nitrite can be harmful to humans and aquatic life.

Phosphorus parameters commonly analyzed for
are Ortho-Phosphate (PO 4), Soluble Reactive
Phosphorus (SRP), Total Dissolved Phosphorus
(TDP), and Total-P (TP). Particulate phosphorus is
calculated as the difference between TP and TDP.
Phosphorus occurs in natural waters as one of the
forms of phosphates: ortho- or reactive phosphate,
meta- or poly- (condensed) phosphate (requires hot
acid digestion) and organic phosphate (requires
severe digestion). Phosphates enter water supplies
from soil runoff, cleaning operations, water
treatment, boiler blowdown and sewage. Although
necessary for plant growth, too much phosphate
causes excessive growth of aquatic plants and
eutrophication of fresh water bodies.


The current SWIM Plan (SFWMD, 1990) focuses
on TP. Hence, the minimal analysis of a water
sample for south Florida should include TP.
However, TP includes particulate forms of
phosphorus, the amount of which can be greatly
influenced by sampling procedures. Hence, it is
advisable to also analyze samples for TDP. Ortho-P
and SRP are of limited value if monitoring is being
conducted for the purpose of complying with terms
of the SWIM Plan.

Water sample collection devices vary widely in
complexity and cost: samples can be manually
dipped from a body of water, one at a time, using
specially prepared containers; sophisticated
autosamplers are available that collect a series of
samples at equal time intervals or at specific times
or in amounts proportional to flow. Descriptions,
costs, and benefits of using the different sample
collection tools will be discussed. At times,
phosphorus concentrations of the soil solution are
also helpful in assessing BMP efficacy. Hence,
instruments for extracting this water in situ will
also be discussed herein.

Sample Collection and Storage

Preparing Bottles for Water Samples
Containers for collection of water samples for
nitrogen and phosphorus analyses should be made
out of nalgene or some other inert material.
Sample bottle sizes generally should range from
250 to 500 mL to ensure that an adequate sample
will be available for re-analysis when necessary.
The cost of the special bottles will vary according to
size and style.

Prior to use, the sample bottles should be washed
with a phosphate-free detergent, rinsed with
distilled water, rinsed in a dilute hydrochloric acid
(HC1) solution, rinsed with distilled water again,
and dried. The bottles should be capped with foil,
saran wrap, or bottle caps (washed and rinsed in
the same manner as the bottles themselves) to
protect against dust particles and other
contaminants (i. e., free ammonia in the air,
insects) from entering the containers during
storage. Once prepared for receiving water
samples, nothing except the water to be sampled
should come in contact with the insides of the
bottles or caps.

The proper labeling of the sample bottles is
critical to a successful water quality monitoring







program. Bottles should be: labeled in the field as
the sample is being collected to ensure proper
identification. Pre-labeling bottles in the
laboratory before taking them to the field can cause
confusion for the person collecting samples as he or
she searches for the appropriate bottle.

Additionally, field labeling forces the collector to
be fully aware of the site being sampled, limiting
the potential for mislabeling. It may be desirable
to label a bottle for a site even if no water is
available to sample at the site. This ensures that
the receiving personnel in the laboratory know that
the site was visited and no sample was available.

The label should include the time, date, site,
station, and name of the person collecting the
sample. For best results, use waterproof/
permanent marking pens and write directly on the
bottle. The writing will come off in the washing
procedure. Alternatively, self-adhesive waterproof
labels can be used. Removal of the labels, however,
can be a time consuming, messy task.

Grab Sampling
Grab samples are manually collected by a person
present at the site. They may be taken from a
water body randomly, systematically, or at regular
intervals such as daily, weekly, or monthly (see
Izuno, Bottcher, and Davis, 1991 for details). These
samples are generally used for establishing
nutrient concentrations at specific points in time.
Grab samples are useful for establishing long-term
trends or point-in-time concentrations.

Grab samples can be dipped manually or
pumped from a body of water (Izuno, Bottcher, and
Davis, 1991). Pumping is the recommended
method. In this case, a suction strainer assembly
and a peristaltic pump are necessary. The suction
strainer is simply a coarse filtering device with
holes small enough to prevent the passage of
material too big to pass through the suction hose.
These strainers are commercially available from
several different companies that manufacture
water sampling instruments.

Alternatively, suction strainers can be con-
structed out of non-corrosive, chemically inert ma-
terials. The strainer should be attached to a rigid
shaft for ease in lowering the unit to the desired
depth in the water body. A hose should be attached
to the strainer and can be connected to the pump
inlet hose. A battery-operated peristaltic pump is
used to pump the sample into the bottle from the


desired depth (see Izuno, Bottcher, and Davis,
1991, for determining appropriate depth).

Where adequate water is available for grab
samples (i. e., in canals or ditches full of water), the
sample bottle should be rinsed with water from the
source being sampled. To do so, simply collect a
sample as would normally be done, and empty the
bottle before collecting the sample for return to the
laboratory. Do not just dip water from the surface
for the rinse process since the surface of the water
body may have a different chemical and biological
make-up than the water at the desired depth.

The cost of the suction strainer assembly is
approximately $50. A suitable peristaltic pump is
manufactured by Tat Engineering Company* and
costs less than $500. Rechargeable 12-volt ni-cad
or lead acid batteries are available from numerous
vendors. The number of strainers and pumps nec-
essary will depend upon the number of sampling
locations, the number of samples desired, and the
number of personnel assigned to the task. The
equipment necessary for collecting grab samples is
shown in Plate 1.


Plate 1: Collecting water grab samples using a pump with
suction strainer arrangement.

Autosampling
An autosampler is a device that automatically
collects water at preset times, on preset intervals,
and in preset volumes. The instrument consists of
a timer, controller, pump, sample distributor, and
sample bottles. The timer unit can be programmed
to initiate a sampling event and to continue taking
samples on set time increments. Alternatively,
electronic pulses from flow sensors can be used to
trigger sample collection.







A typical autosampler, the ISCO 2900* (ISCO,
Inc., 1987) is an example of a portable device
designed to collect up to 24 separate sequential
(discrete) samples from a liquid source. This
autosampler will be used for the following
discussion although several other models are
available.

In the time mode, the interval between samples
may be set from 1 to 9999 minutes in one minute
increments. In the flow mode, the interval may be
set from 1 to 9999 flow pulses in 1 pulse
increments. A sample may also be collected
manually at any time by simply pushing a button.

Sample volumes of up to 500 mL may be selected
in 10 mL increments. Samples are collected in
custom fitted polyethylene bottles. Each
autosampler holds 24 bottles. It is suggested that a
spare set of clean, empty bottles be available to
replace filled ones at the time of collection.

A standard feature of most autosamplers is a
"bottles per sample" or "samples per bottle"
multiplexer. In the case of the ISCO autosampler,
this allows up to 24 bottles to be filled at each
sampling interval, or up to four samples to be
placed in each sample bottle.

The autosampler uses a peristaltic pump system
to transport the sample from the source to the
sample bottle. The sample is under pumped flow at
all times. The only materials in contact with the
sample are the vinyl or teflon suction line, the
polypropylene and stainless steel inlet strainer
(optional, but recommended), the silicone rubber
pump tubing, and the polyethylene sample bottles.

Each sampling cycle includes an air pre-purge
and post-purge to clear the suction line both before
and after sampling.

The individual sample bottles are held in place
in the autosampler base by a retaining ring. The
ring is held in place by four large rubber bands that
are attached to the bottom of the base. Each of
these rubber bands is stretched up and connected
onto a corresponding hook located on the ring.
Note that the retaining ring is necessary only if ice
is used to cool the samples. The water from the
melting ice will cause the bottles to float,
interfering with the sampler's operation.

The suction line is the piece of tubing that
extends from the sampler's pump to the liquid


source from which a sample is to be collected. The
maximum suction lift is 26 feet.

During the course of monitoring, it may be
necessary to replace the sampler suction tubing for
one of several reasons. The suction tubing may
become worn, cut, contaminated, or otherwise
damaged. Algae growth inside the tube is also a
cause for replacement. It is good practice to
periodically inspect the suction line for damage.

Autosamplers are available in many levels of
sophistication and with a wide assortment of
features. For example, ISCO* also offers a
composite sampler. Accurate, representative
samples are collected in a single, composite sample
container. Four to 19 L glass or polyethylene
containers are available for composite sampling.

Samples can be based on either time or flow.
The flow mode is controlled by external flow meter
pulses. This requires a separate flow meter to be
attached to the control box on the autosampler by a
cable. The flow meter is then programmed to
trigger the collection of a sample after the passage
of a preset flow volume (for example a sample
would be collected after every 1000 gallons passed
the monitoring station), resulting in a composite
sample that is composed of subsamples
proportional to flow rates. Flow meter signal
requirements are a 12-volt DC pulse or an isolated
contact closure of at least 25 milliseconds duration.

Maximum sample volume is 990 mL in the
composite sample. A built-in float mechanism
provides a fail-safe shut off to eliminate overfilling.
Sample volumes can be proportionally increased or
decreased to minimize the potential for overfilling.


Plate 2: A typical portable autosampler and Its major
components.






extracted from the lysimeter using the same
peristaltic pump used for grab sampling.

The pump hose should be rinsed with distilled
water before pumping a sample to avoid cross-
*contamination between lysimeters. It is important
T to make sure that all the rinse water is pumped out
of the tubing prior to filling the sample bottle.
S- t Pumping some lysimeter water through the tube
prior to filling the sample bottle will ensure that
the sample nutrient concentrations are not diluted
with the rinse water. Alternatively, a vacuum flask
S- and vacuum pump can be used to extract the
Sample without passing the sample through the
pump tubing This method is preferred if small
Plate 3: Installation of an autosampler and water level pump tubing. This method is preferred if small
recorder in a main farm canal. sample volumes are available.

The sccations te tbinad the Suction lysimeters can be purchased already
The specifications of the tubing and others b om uc e sg m i
accessories are identical to those described for the assembled or manufactured using commercially
available parts. Each unit costs about $60. A
autosampler previously discussed.
service kit that includes a hand vacuum pump
sts for a gle ut w n must also be purchased. This kit costs a little over
Costs for a single unit with necessary
accessories, but without shelter, start at
approximately $2,000. A typical autosampler is
shown in Plate 2. Plate 3 shows the shelter and
strainer assembly installed in a farm canal.

Soil Solution Sampling/Suction Lysim-
eters
The suction lysimeter is installed in the soil such
that there is a tight fit between the porous cup and
the soil. Without the tight fit, the unit will not
extract water from the soil unless the cup is below
the water table. The assembly should be left in the
field for a suitable period of time prior to use for
collecting samples for analysis. This allows the
ceramic cup to chemically equilibrate with the soil
water. Pumping samples through the system to
flush it is also advisable prior to use.

Any section of the lysimeter tube that protrudes
above the ground surface should be painted black.
Sunlight will pass through the thin walled white
PVC pipe and allow the growth of algae within the
tube. Painting the unit black will alleviate this
problem.

When sampling, the user must first apply a
vacuum to the unit. The vacuum must be held in
the lysimeter for at least two hours to ensure that
an appropriate amount of water will enter the tube.
If the cup is below the water table then very little
time will be needed. Samples may then be
Plate 4: A suction lysimeter and the necessary pumps for col-
lecting soil solution samples.






$100. Suction lysimeter components or complete
assemblies are manufactured by TIMCO
Manufacturing Company'; Soil Moisture,
Incorporated'; and other soil-water specialty
companies. Plate 4 illustrates the components of a
soil solution sampler and the necessary sample
extraction pumps.

Sample Preservation
Grab and soil solution samples are collected
manually and, therefore, require little in the way of
sample preservation in the field. Essentially all
that is required is that the samples be kept cool
(40C) during transportation from the field to the
laboratory. This is easily accomplished by placing
samples in an ice chest or cooler filled with ice.

Autosamplers were originally designed to collect
numerous samples automatically over a variable
length of time. Each sample, therefore, has a
different length of time that it remains in the
sampler between collection and pick-up times.


Additionally, autosampler capacities are generally
up to 24 samples, enabling the sampler to operate
over long time periods prior to pick-up. Thus,
autosamplers require more sophisticated means of
maintaining the viability of collected samples.

Preservation begins in the field with the
appropriate shelter. The shelter should protect the
autosampler from direct sunlight while ensuring
adequate ventilation. Refrigerated shelters are
available for instances where the time between
sampling and pick-up is considerable. In other
cases, a ventilated shelter will suffice if ice is
placed in the autosampler base where the sample
bottles are stored. Ice melts and, therefore, there is
a limitation as to how effective the method is.

The autosamplers are designed with insulated
bases such that with uncontained ice, the samples
will be kept 14C below ambient air temperature
for 24 hours. After 48 hours the samples will be
5C lower than ambient air temperature. Samples


Table 1: Required water sample containers, preservation techniques, and maximum storage times as suggested by the EPA (1984).
Parameter Container1 Preservation Maximum Storage
Time
Ammonia P, G Cool, 4C, 28 days
H2SO4 to pH<2

Color P, G Cool, 40C 48 hours

Hardness P, G HNO3 to pH<2, 6 months
H2SO4 to pH<2

pH P, G None Analyze
immediately

Kjeldahl and organic N P, G Cool, 4C, 28 days
H2SO4 to pH<2

Nitrate P, G Cool, 40C 48 hours

Nitrate-Nitrite P, G Cool, 40C 28 days
H2SO4 to pH<2

Nitrite P, G Cool, 40C 48 hours

Phosphorus (Total) P, G Cool, 40C 28 days
H2SO4 to pH<2

Turbidity P, G Cool, 40C 48 hours
'Polyethylene (P) or Glass (G).






that will be analyzed for ammonia should be
acidified with sulfuric acid (H2SO4) to pH<2 upon
collection.

Once the samples are brought into the
laboratory, preservation activities must continue.
There are a number of procedures to be used,
depending on the nutrient parameters to be
measured. The EPA (1984) provides information as
to the treatment of the samples and acceptable
storage times. The storage and preservation
specifications for chemical parameters most often
measured in agricultural water are listed in
Table 1.

Laboratory Water Analysis Instru-
ments and Procedures

Sample Filtration
Water samples can be filtered in the field,
especially if grab samples are being collected.
Special equipment exists, enabling the filtration of
the sample to occur as the sample is being pumped
from the water body. Obviously, when numerous
autosamplers are in use, field filtration techniques
are not applicable nor practical.

When samples are brought in from the fields,
they are filtered immediately. The filtration step
allows for the determination of the concentrations
of dissolved nutrient species (i. e., NOg, NH +,
TDKN, Ortho-P, and TDP) without interference
from particulate matter.

The filtration process involves passing the
sample through a 0.45 pLm chemically inert
(polysulfone) filter membrane into a properly
prepared vial. The filter membranes should be
rinsed in de-ionized water prior to use. Once
rinsed, to avoid contamination, they should not be
touched directly by human hands Each filter
membrane should only be used once.

A vacuum filtration apparatus can be purchased
to accelerate the process. Alternatively, a high-
capacity vacuum filtration unit can be constructed
out of readily available materials. Such a unit is
shown in Plate 5.

To assemble a multi-sample filtration unit
requires plexiglass, caulking, solenoid valves,
electrical materials, filter funnels, O-rings, and
plastic tubing. The primary expense will be the
vacuum pump, which costs approximately $1,400.


Plate 5: A "home-made" high capacity vacuum filtration unit.

The cost of filtration will vary with the sample
load. The membrane filters are the major expense,
as they cost approximately $60 per 100.

Sample Digestion
Water samples are digested prior to analyses for
TDKN, TKN, TDP, and TP analyses. The Kjeldahl
digestion process involves adding acid to the
sample and heating it at 200C for 1 hour. The
heat is then turned up to 3600C for 1 1/2 hours to
break down complex chemical compounds into ones
suitable for colorimetric analyses. Primarily, the
process converts complex compounds of nitrogen
and phosphorus to NH + and PO respectively.

In addition to the major hardware, various
laboratory utensils such as pipettes, repipettors,
balances, and an assortment of glassware will be
necessary. The costs of chemicals necessary for the
digestion procedure, as well as potential hazardous
waste disposal (method dependent), are also major
expenses to consider.

The materials and apparatus necessary for
sample digestions are a major expense. Digestion
blocks (heating units) are available in 6, 12, 20, and
40 sample capacity models. Commercial suppliers
offer the units at prices ranging from $3,500 to
$6,000. The digestion tubes (specialized test tubes)
cost approximately $700 for a set of 40. Stands for
holding the digestion tubes cost about $300. The
necessary high temperature thermometers cost
about $40 each. Additionally, exhaust systems and
acid fume hoods are necessary. Fume hoods cost
between $4,500 and $11,000, depending on size and
features.







The total cost of setting up a laboratory for
digesting water samples ranges from $14,000 to
$23,000. This figure is based on a sample
processing capability of approximately 80 samples
per digestion. The figure does not include the costs
of skilled labor, electricity, waste disposal,
equipment maintenance, distilled water, and
environmentally controlled laboratory space, all of
which will add greatly to sample digestion costs.

pH
The pH of water is measured using a pH meter.
The pH of a sample is defined as the logarithm of
the reciprocal of the concentration of free hydrogen
ions. Acid waters will have pH values below 7.
Alkaline waters will have pH values ranging from
above 7 to 14. A pH of seven indicates that the
water is neither acidic nor alkaline.

Surface water samples will generally range in
pH from five to eight. The pH of soil water will
affect the amount of nitrogen and phosphorus
available for plant use and drainage water loading.
Higher pH values will result in less available
phosphorus for plants.

Common causes of acidic surface waters are acid
rainfall due to atmospheric carbon dioxide and
other airborne pollutants, runoff from mining
spoils, and decomposition of plant materials. Acidic
ground water can also be caused by the above
factors, but is mostly controlled naturally by the
equilibrium relationship with surrounding
minerals. For example, because of the geologic
composition of the aquifer (limestone), most ground
water in Florida is alkaline, with pH values
ranging from 7 to 10 (Haman and Bottcher, 1986).

The cost of a typical pH meter starts at $500.
They range in sophistication from simple portable
units to computer-interfaced instruments.

Electrical Conductivity
The electrical conductivity (EC) of a water
sample is a measure of the total amount of salts in
solution, measured by the ability of the solution to
conduct electricity. Electrical conductivity is
usually expressed in units of pmho/cm (or dS/m).
There is a correlation between the electrical
conductivity and the amount of extractable
phosphorus available. As the conductivity
increases, the amount of extractable phosphorus
increases (Stumm et al., 1981). Thus, EC provides


a potential indication of the amount of phosphorus
in the sample. Conductivity meters range in price
from $600 to $2,000.

Hardness
Water hardness is defined as the concentrations
of calcium and magnesium ions, expressed in units
of mg/L or ppm. These two cations readily combine
with phosphate to form particles that settle out of
solution. Hence, hardness has a potential
importance as an influence over the amount of
soluble phosphorus in a water sample. Hardness is
measured using the EDTA titrimetric method
(APHA, 1985). Titrations can be done manually
using a pipette or using partially automated
instruments that range in cost from $1,000 to
$6,000, depending on the level of sophistication
desired.

Turbidity
Turbidity in water is caused by suspended
matter such as clay, silt, finely divided organic
matter, soluble colored organic compounds,
plankton, and other microscopic organisms. These
solid particles can absorb and/or reflect light and
cause the water to appear cloudy. The extent of the
"cloudiness" of the water sample is represented by
the turbidity level.

The suspended particles that cause turbidity can
contain nitrogen and phosphorus. Hence, the
turbidity of a water sample has the potential for
being an indicator of total phosphorus in the
sample, especially in cases where a large proportion
of the phosphorus in the sample is not dissolved.

The standard methods for the determination of
turbidity are the nephelometric and visual
methods. The turbidity of a water sample
measured using a nephelometric method (APHA,
1985) is reported in "nephelometric turbidity units"
(NTU's). The visual Jackson Turbidity Method
(APHA, 1985) reports turbidity in "Jackson
turbidity units" (JTU's). Meters for measuring tur-
bidity range in cost from about $1,400 to $2,000.

Nitrogen and Phosphorus
Colorimetry is one method of analysis used to
determine the concentrations of nitrogen and
phosphorus in a water sample. The procedure
involves the use of a colorimeter as a detection
device. Essentially, upon chemical treatment in an







explicit manner, a water sample will yield unique
color traits, dependent on the concentrations of nu-
trients in the sample.

Colorimeters range from simple to
extraordinarily sophisticated instruments. In
situations that require analyses of a large number
of samples in a limited amount of time, it is
advantageous to use an autoanalyzer. An
autoanalyzer is simply a colorimeter that has most
of its functions automated, including the addition of
the chemicals necessary to produce the measurable
color.

Autoanalyzers are capable of analyzing an
extremely large number of samples while
eliminating much of the potential for human error.
The instruments are, however, subject to the usual
maintenance problems associated with electronic
and computerized equipment operating in "wet
chemistry" environments.

The analytical procedures used to measure
nitrogen and phosphorus are detailed in APHA
(1985). The procedures can be automated using
high-capacity autoanalyzers manufactured by
Technicon* or ALPKEM*, or comparable
instruments. For laboratories with limited sample
loads, the less sophisticated, but still computerized
(if desired), Technicon AA-IV, AA-II*, or comparable
machines will suffice.

Prices for these instruments range from
approximately $2,000 to $70,000, depending on the
daily sample capacity desired and the number of
nutrient parameters that can be analyzed
simultaneously. These figures do not include the
cost of maintenance for the instrument, nor the
chemicals and replacement parts necessary for day-
to-day operation. They do include the computer
hardware and software for the more sophisticated
units.

Field Test Kits
Many field test kits are available for analyzing
water samples for nitrogen and phosphorus
concentrations. Accuracy, range, and detection
limits vary among kits. Specifications of a
sampling of these kits are listed in Table 2.

Field test kit data are useful as indicators of
nutrient concentrations, with the general
consensus being that the resulting concentrations
will be "ball park" figures.


Because of the limited sensitivities and/or
detection limits of the kits, the resulting data will
have limited usefulness in matters concerning
south Florida, where arguments occur over
concentrations below 0.03 ppm (mg/L). The user
must also be extremely careful regarding what
nutrient species are actually being measured. For
example, a kit measuring "total phosphorus," with
no digestion procedure involved, is probably only
measuring total soluble inorganic phosphorus.
Acid reagents used in these kits will account for
some, but not all, of the particulate organic and
inorganic compounds.

Hach and LaMotte Chemical Companies* (Hach
Company, 1990; LaMotte Chemical Company,
1991) are two of many suppliers of test kits for
nitrogen and phosphorus analyses. Prices range
from about $50 to $500, depending upon the
method or chemistry used. The test kits are
reliable as long as the user is aware of their
inherent limitations. Field test kits should not be
looked upon as inexpensive substitutes for
laboratory analyses.

Quality Assurance/Quality
Control (QA/QC)
Quality assurance is attained by employing
adequately trained and experienced personnel,
having good physical facilities and equipment,
using certified reagents and standards, frequently
servicing and calibrating instruments, and using
replicate and known-addition sample analysis.

It is desirable that QA/QC programs are
approved by the Department of Environmental
Regulation. A good analytical quality control
program consists of an organized plan for sampling
procedures, sample custody, analytical procedures,
calibration procedures and frequency, routine
maintenance of equipment, quality control checks
(matrix spikes, method blanks, standard
calibration, check samples, laboratory duplicates,
field quality controls, precision, accuracy), data
reduction, data validation, and reporting.

Quality assurance/control is important to make
sure each organization or laboratory involved with
sample collection or analysis has the responsibility
of implementing procedures that assure that the
precision, accuracy, and comparability of the data
submitted is of a known and documented level of
quality.






Table 2: Nutrient species, range, smallest increment, and method/chemistry for various field test kits (Hach Company', 1990).
Nutrient Range Smallest Method/Chemistry
Species (mg/L) Increment
(mg/L)


Ammonia (NH3N)
Low range
Mid range



Nitrate (NO3N)
Low range


High range



Nitrate/Nitrite (NO N/NO;N)


Nitrite (NO N)
Low range


High range


Orthophosphate
(reactive)


0 to 0.8
0 to 2.5
0 to 3.0
0 to 3.0


0 to 0.4
0 to 1.0
0to 10.0
0 to 30
0 to 50
0 to 50


0 to 0.5

0 to 50


0 to 0.2
0 to 0.5
0to 1.0
0 to 100
0to 150
0 to 2000


0 to 3
0 to 5
0 to 5
0 to 50


0.2
0.5
0.1
0.1


0.02
0.02
0.2
1
10
1


0.01

1.0


0.01
0.01
0.2
2
5
40

0.1
0.1
1
1


Color cube/Salicylate
Color cube/Nessler Reagent
Color disc/Nessler Reagent
Colorimeter/Nessler Reagent


Color disc/Cadmium Reduction
Color disc/Cadmium Reduction
Color disc/Cadmium Reduction
Colorimeter/Cadmium Reduction
Color cube/Cadmium Reduction
Color disc/Cadmium Reduction


Color disc/Cadmium Reduction,
Diazotization
Color disc/Cadmium Reduction,
Diazotization


Colorimeter/Diazotization
Color disc/Diazotization
Color cube/Diazotization
Color disc/Ferrous sulfate
Colorimeter/Ferrous sulfate
Colorimeter/Ferrous sulfate

Colorimeter/Ascorbic acid
Color disc/Ascorbic acid
Color cube/Ascorbic acid
Color disc/Ascorbic acid


Orthophosphate
(Stannous method)


Total phosphate
(ortho-, meta-, organic)


0 to 2, 0 to 10
0 to 4.5
0 to 45


0to 1
0 to 5
0 to 50


0.02
0.1
1


Color ampule/Stannous
Color disc/Stannous
Color disc/Stannous

Color disc/Ascorbic acid
Color disc/Ascorbic acid
Color disc/Ascorbic acid


Summary
Collecting water quality samples is not a task to
be taken lightly. There are specific procedures to
follow and equipment to use in order to ensure
viable data. Activities that may seem trivial, such
as labeling and filling bottles with water, must be
conducted properly. Equipment and procedures for


collecting grab, soil solution, and automatically
time sequenced and flow proportioned water
samples have been discussed, along with the
approximate costs of the equipment.

The proper handling, preservation, and storage
of water samples were detailed. Guidelines were
given regarding sample preservation techniques







and storage times. If commercial laboratories are
used for sample analysis, both the grower's and the
company's sample storage and handling must be
considered.

The basic laboratory equipment necessary for
processing samples was briefly discussed, including
cost estimates. This information was provided to
help grower's appreciate the costs of analyzing
samples and the importance of a well thought out
water quality monitoring program.

Field test kits are available for determination of
nitrogen and phosphorus concentrations. However,
the user must be fully aware of what nutrient
species the kit is designed to detect. The user
should also be aware of the resolution of the test
kits. Although these test kits can be very accurate,
they should not be considered to be a substitute for
laboratory analysis. It should also be stressed that
the data resulting from any nutrient analysis
method is only as good as the level of care that was
taken in sample collection and preservation.

References
American Sigma. 1985. American Sigma.
Middleport, New York.

APHA. 1985. Standard Methods For the Examina-
tion of Water and Wastewater, 16th ed. Ameri-
can Public Health Association, Washington,
D.C.

Bottcher, A. B. and F. T. Izuno, eds. 1991. Water,
Agriculture, and the Environment in South
Florida. Book draft submitted to University
Presses, Gainesville, Florida. (In review).

EPA. 1984. Guidelines Establishing Test
Procedures for the Analysis of Pollutants Under
the Clean Water Act. Federal Register, Part
VIII, Vol. 49(209). Environmental Protection
Agency, Washington, D. C. p. 28. October.

Florida Department of Administration. 1976.
Final report on the special project to prevent
eutrophication of Lake Okeechobee. 341 pp.
November.


Hach Company. 1990. Products For Analysis
1990. Loveland, Colorado. January.

Haman, Dorota Z. and Del B. Bottcher, 1986.
Home Water Quality and Safety. IFAS
Extension Circular 703. Florida Cooperative
Extension Service, Institute of Food and Agricul-
tural Sciences, University of Florida, Gainesville.
May.

ISCO, Inc. 1987. Instruction Manual Model 2900
Sampler. Part #60-2903-023. Lincoln,
Nebraska. March.

Izuno, F. T., W. A. Davis, and A. B. Bottcher. 1991.
Terms related to agricultural nutrient loading in
south Florida. IFAS Extension Circular 905.
Florida Cooperative Extension Service, Institute
of Food and Agricultural Sciences, University of
Florida, Gainesville. February.

LaMotte Chemical. 1991. Water Testing Products.
Chestertown, Maryland.

LOTAC I. 1986. Final Report. Submitted to the
Governor of the State of Florida, the Secretary of
the Department of Environmental Regulation,
and the Governing Board of the South Florida
Water Management District. Tallahassee.

LOTAC II. 1990. Final Report. Submitted to the
Governor of the State of Florida, the Secretary of
the Department of Environmental Regulation,
and the Governing Board of the South Florida
Water Management District. Tallahassee.

SFWMD. 1990. Surface water improvement and
management plan for the Everglades, Final
Draft. South Florida Water Management
District, West Palm Beach. September.

Stumm, Werner, James J. Morgan. 1981. Aquatic
Chemistry An Introduction Emphasizing
Chemical Equilibria in Natural Waters, 2nd ed.
New York, New York.


COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLORIDA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES, John T. Woeste,
Director, in cooperation with the United States Department of Agriculture, publishes this information to further the purpose of the May 8 and June
30, 1914 Acts of Congress; and is authorized to provide research, educational information and other services only to individuals and institutions that
function without regard to race, color, sex, age, handicap or national origin. Single copies of extension publications (excluding 4-H and youth
publications) are available free to Florida residents from county extension offices. Information on bulk rates or copies for out-of-state purchasers
is availablefrom C.M. Hinton, Publications Distribution Center, IFAS Building 664, University of Florida, Gainesville, Florida 32611. Before publicizing
this publication, editors should contact this address to determine availability. Printed 10/92.




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