||Responses of zooplankton and 'Chaoborus' to temephos in a natural pond and in the laboratory /
Helgen, Judith Cairncross. ;
Helgen, J. C. ;
Larson, N. J. ;
Anderson, R. L.
||Environmental Research Lab.-Duluth, MN. ;Saint Olaf Coll., Northfield, MN. Dept. of Biology. ;Minnesota Pollution Control Agency, St. Paul.
|| U.S. Environmental Protection Agency, Office of Research and Development, Environmental Research Laboratory--Duluth,
Water pollution ;
Phosphorus organic compounds ;
Life cycles ;
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
||15 pages ; 28 cm
Application of the organophosphorus insecticide temephos to a natural pond in central Minnesota was followed by reduction within 24 hr in all cladocerans, in Diaptomus leptopus and in Chaoborus americanus, and increases in cyclopoid copepods, copepod nauplii and rotifer Keratella cochlearis. Daphnia pulex that reappeared 35 days post-application were ex-ephippial. After application, reproduction of cladocerans and Diaptomus was markedly reduced compared to the previous year, an effect attributed to temephos. Daphnia population density was strongly reduced into the fall season, long after the spring applications, compared with both a reference pond's and the previous season's populations. On-site bioassays demonstrated 24-hr mortalities of Daphnia and Chaoborus that were comparable to the population decreases in the pond. Laboratory toxicity tests showed Daphnia was the most sensitive followed by Chaoborus and Diaptomus.
"Journal article." "EPA/600/J-88/308." "Published in Archives of Environmental Contamination and Toxicology, 17:459-471, 1988 (July). Microfiche.