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Effects of chronic exposure to simazine on the cladoceran, Daphnia pulex

September 1, 1982

The effects of chronic exposure to simazine, an s-triazine herbicide, on the cladoceranDaphnia pulex were evaluated under laboratory conditions. The daphnids were exposed to simazine concentrations corresponding to previously calculated 48-hr LC5 and LC20 values and the effects on survival, growth, reproduction, and behavior were monitored daily for 26 days. Survival ofD. pulex in 20 mg/L simazine averaged 9.6±1.7 days. Most mortality in 4 mg/L occurred between days 21 and 25, and 65% of the daphnids were dead by day 25. Simazine interfered with molting, and growth was reduced in both concentrations tested. Reproductive maturation was delayed by about one molt cycle (3 days at 20°C) inD. pulex exposed to 4 mg/L simazine and was prevented in daphnids exposed to 20 mg/L. Numbers of live young and broods produced by daphnids in 4 mg/L were significantly lower than those produced by controls.

Publication Year 1982
Title Effects of chronic exposure to simazine on the cladoceran, Daphnia pulex
DOI 10.1007/BF01056369
Authors K. M. Fitzmayer, J. G. Geiger, Michael J. Van Den Avyle
Publication Type Article
Publication Subtype Journal Article
Series Title Archives of Environmental Contamination and Toxicology
Index ID 1013873
Record Source USGS Publications Warehouse
USGS Organization Leetown Science Center