Biological field and laboratory methods for measuring the quality of ...

The role of aquatic biology in the water
pollution control program of the U. S.
Environmental Protection Agency includes field
and laboratory studies carried out to establish
water quality criteria for the recognized
beneficial uses of water resources and to
monitor water quality.
Field studies are employed to: measure the
toxicity of specific pollutants or effluents to
individual specitf.> or communities of aquatic
organisms under natural conditions; detect
violations of water quality standards; evaluate
the trophic status of waters; and determine
long-term trends in water quality.
Laboratory studies are employed to: measure
the effects of known or potentially deleterious
substances on aquatic organisms to estimate
"safe" concentrations; and determine environmental
requirements (such as temperature, pH,
dissolved oxygen, etc.) of the more important
and sensitive species of aquatic organisms. Field
surveys and water quality monitoring are
conducted principally by the regional
surveillance and analysis and national enforcement
programs. Laboratory studies of water
quality requirements, toxicity testing, and
methods development are conducted principally
by the national research programs.
The effects of pollutants are reflected in the
population density, species composition and
diversity, physiological condition and metabolic
rates of natural aquatic communities. Methods
for field surveys and long-term water quality
monitoring d"'· sribed in this manual, therefore,
are directed iTIa:ily toward sample collection
and processing, organism identification, and the
measurement ef biomass and metabolic rates.
Guidelines are also provided for data evaluation
and interpretation.
There are three basic types of biological field
studies; reconnaissance surveys, synoptic
surveys, and comparative evaluations. Although
there is a considerable amount of overlap, each
of the above types has specific requirements in
terms of study design.
Reconnaissance SUI veys may range from a
brief perusal of the stW.i)' area by boat, plane, or
INTRODUCTION
ix
car, to an actual field study in which samples are
collected for the purpose of characterizing the
physical boundaries of the various habitat types
(substrate, current, depth, etc.) and obtaining
cursory information on the flora and fauna.
Although they may be an end in themselves,
reconnaissance surveys are generally conducted
with a view to obtaining information adequate
to design more comprehensive studies. They
may be quantitative or qualitative in approach.
As discussed in the biometrics section, quantitative
reconnaissance samples are very useful for
evaluating the amount of sampling effort
required to obtain the desired level of precision
in more detailed studies.
Synoptic surveys generally involve an attempt
to determine the kinds and relative abundance
of organisms present in the environment being
studied. This type of study may be expanded to
include quantitative estimates of standing crop
or production of biomass, but is generally more
qualitative in approach. Systematic sampling, in
which a deliberate attempt is made to collect
specimens from all recognizable habitats, is
generally utilized in synoptic surveys. Synoptic
surveys provide useful background data, are
valuable for evaluating seasonal changes in
species present, and provide useful information
for long-term surveillance programs.
The more usual type of field studies involve
comparative evaluations, which may take various
forms including: comparisons of the flora and
fauna in different areas of the same body of
water, such as conventional "upstreamdownstream"
studies; comparisons of the flora
and fauna at a given location in a body of water
over time, such as is the case in trend
monitoring; and comparisons of the flora and
fauna in different bodies of water.
Comparative studies frequently involve both
quantitative and qualitative approaches. However,
as previously pointed out, the choice is
often dependent upon such factors as available
resources, time limitations, and characteristics of
the habitat to be studied. The latter factor may
be quite important because the habitat to be
studied may not be amenable to the use of quan-