SYMPOSIA PAPER Published: 01 January 1988
STP10288S

Comparison of Estimates of Effects of a Complex Effluent at Differing Levels of Biological Organization

Source

Impact of a toxic municipal sewage effluent containing textile dyes was evaluated using standard acute and chronic single-species tests and a microcosm test using indigenous microbiota from the receiving stream. Estimated effect levels were compared with the calculated in-stream waste concentration and measured impacts on stream microbiota and macrobenthos. Acute tests examined effluent effects on Daphnia pulex, and short-term chronic effluent dilution tests were conducted using Ceriodaphnia dubia and larval Pimephales promelas. Microcosm tests examined effluent effects on the structure and function of microbial communities on artificial substrates. Additional tests examined effects of receiving stream water on C. dubia and microcosms.

Effluent concentrations of 70% were acutely toxic in median effective concentrations) to D. pulex. Estimates of the no-observable-effect concentration (NOEC) were 10 and 7.5% for C. dubia and P. promelas, respectively. Responses in the microcosm systems were nonlinear and showed significant subsidy of both structure and function at concentrations of >30% and toxicity at concentrations >30%. Tests of receiving stream water below the effluent outfall showed a slight depression of reproduction in C. dubia and recovery to upstream levels for water sampled from farther downstream. Microcosms treated with ambient stream water did not show effects on taxonomic richness, but reduced midmorning oxygen levels were observed for microcosms dosed with water from stations below the effluent outfall. Surveys of in-stream microbiota and macrobenthos confirmed adverse impacts below the discharge and indicated recovery 11 km downstream. Microcosm tests were generally less sensitive than single-species tests in detecting toxicity of the effluent. None of the laboratory tests corresponded to observed in-stream effects. The sensitivity of the tests may have been improved by improving the test conditions, including continuous replacement of effluent, as was done in larval P. promelas tests. To be effective in predicting in-stream effects, the design of intensive toxicity surveys should make every effort to mimic local conditions.

Author Information

Pratt, JR
School of Forest Resources, The Pennsylvania State University, University Park, PA
Mitchell, J
State Water Control Board, Commonwealth of Virginia, Richmond, VA
Ayers, R
State Water Control Board, Commonwealth of Virginia, Richmond, VA
Cairns, J
University Center for Environmental and Hazardous Materials Studies, Virginia Polytechnic Institute and State University, Blacksburg, VA
Price: $25.00
Contact Sales
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Developed by Committee: E47
Pages: 174–188
DOI: 10.1520/STP10288S
ISBN-EB: 978-0-8031-5027-0
ISBN-13: 978-0-8031-1180-6