SYMPOSIA PAPER Published: 01 January 1985
STP33568S

Biological Effects of Continuous and Intermittent Dosing of Outdoor Experimental Streams with Chlorpyrifos

Source

Two outdoor experimental streams fed by water pumped from the Mississippi River were dosed with the organophosphorus pesticide chlorpyrifos (the active ingredient of Dursban® and Lorsban 4E® insecticides) for 100 days, and the responses of individual species and communities compared to those of a control stream. Chlorpyrifos was continuously metered into one stream whereas the other received 8 biweekly additions, each lasting 24 h, at 14 times the concentration in the continuously dosed stream. Therefore, nearly equal amounts of pesticide were introduced into each stream during the experiment. The biological study area of each stream was approximately 245 m long, contained a naturally colonizing plant and invertebrate assemblage, and was stocked with fathead minnows and bluegills. Measured system characteristics included macroinvertebrate drift and riffle benthos composition; fish survival, growth, reproduction, food habits, tissue residues, and AChE inhibition; and system functional process indicators (P/R ratios, biodegradation, nitrate and dissolved organic carbon [DOC] concentrations, and bacterial growth and heterotrophic activity).

The macroinvertebrate communities reacted similarly in the continuously and pulse-dosed streams. Species diversity decreased by equal amounts and was still decreasing at the end of the test. Crippling of fathead minnows and reversible acute toxicity symptoms (lethargy, tetany when startled) in bluegills were observed only in the pulse-dosed stream. Fish survived, reproduced, and grew equally well in all streams. There seemed to be good agreement between laboratory and field effect concentrations for fish and invertebrates. Functional process indices, with the possible exception of biodegradation, appeared unaffected and considerably less sensitive than other characteristics measured. The results of the project are discussed in relation to lab to field extrapolation and the need for further testing.

Author Information

Eaton, J
U.S. Environmental Protection Agency, Environmental Research Laboratory-Duluth, Duluth, MN
Arthur, J
U.S. Environmental Protection Agency, Environmental Research Laboratory-Duluth, Monticello Ecological Research Station, Monticello, MN
Hermanutz, R
U.S. Environmental Protection Agency, Environmental Research Laboratory-Duluth, Monticello Ecological Research Station, Monticello, MN
Kiefer, R
College of William and Mary, Williamsburg, VA
Mueller, L
U.S. Environmental Protection Agency, Environmental Research Laboratory-Duluth, Duluth, MN
Anderson, R
U.S. Environmental Protection Agency, Environmental Research Laboratory-Duluth, Duluth, MN
Erickson, R
University of Wisconsin-Superior, Superior, WI
Nordling, B
U.S. Environmental Protection Agency, Environmental Research Laboratory-Duluth, Duluth, MN
Rogers, J
University of Wisconsin-Superior, Superior, WI
Pritchard, H
U.S. Environmental Protection Agency, Environmental Research Laboratory-Gulf Breeze, Gulf Breeze, FL
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Details
Developed by Committee: E47
Pages: 85–118
DOI: 10.1520/STP33568S
ISBN-EB: 978-0-8031-4952-6
ISBN-13: 978-0-8031-0437-2