Biomonitoring of Industrial Effluents
HERBERT W. JACKSON. Chief Biologist
Water Pollution Training Activities
WILLIAM A. BRUNGS, Jr., Aquatic Biologist
Basic and Applied Sciences Program
Federal Water Pollution Control Administration
Cincinnati Water Research Laboratory
4676 Columbia Parkway
Cincinnati, Ohio
INTRODUCTION
Plant operating personnel need to know the general quality of an effluent being discharged at a fairly constant rate and also must be warned if a slug of toxic
material is released to the receiving water. For example, many of the fish kills
resulting from the release of slugs of highly toxic substances could have been prevented had these slugs been detected before the effluent left the plant.
Conventional bioassay procedures can evaluate only single samples taken at
particular times. Continuous-flow bioassays of single grab samples over a long
period of time can be very useful, but do not solve the problem of transient variations. A technique that does permit exercising continuous surveillance over the
toxicity of an effluent is biomonitoring, a concept similar to the one advanced by
Henderson and Pickering (1) for water supplies.
Some progressive plants have met this need to determine effluent quality by
installing aquaria in which fish are exposed to the plant effluent on a continuous
flow-through basis. A "satisfactory" effluent quality is demonstrated by the survival of the fish. Any deleterious change or effect is evidenced either by the
death of the fish or a change in their behavior.   This is biomonitoring.
Conventional bioassays (2, 3, 4) can provide important information about the
actual toxicity of batches of the effluent in terms of TL *s (that concentration
which will kill half of the test animals in some stipulated period of time) and, if
sufficient samples are tested, about the range of variation. This is a relatively
slow process and would be prohibitive on an hourly or even a shift basis. Bioassays should be run from time to time to ascertain the exact toxicity of a waste
even though it is being monitored as outlined below. Such tests also provide essential guidance in setting up appropriate dilutions for continuous monitoring.
The following procedures refer only to toxic wastes having a relatively rapid
action. Wastes, such as cadmium, that have long delayed cumulative effects at
low concentrations (5), oxygen-demanding wastes, radioactive wastes, and others
would either be in-appropriate or would not elicit a recognizable reaction soon
enough to be of use in the following context.
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