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Effect of humic acids on toxicity of DDT and chlorpyrifos to freshwater and estuarine invertebrates
Author(s) -
Mézin Laurent C.,
Hale Robert C.
Publication year - 2004
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/02-431
Subject(s) - chlorpyrifos , pesticide , salinity , organophosphate , invertebrate , environmental chemistry , acute toxicity , toxicity , estuary , cladocera , ecotoxicology , biology , crustacean , daphnia , toxicology , daphnia magna , chemistry , ecology , organic chemistry
Abstract The effects of dissolved humic acids(HA)on the acute toxicities of the organophosphate pesticide chlorpyrifos and the organochlorine pesticide 4,4′‐dichlorodiphenyltrichloroethane (DDT) were assessed by using freshwater crustaceans (Cerio‐daphnia dubia) and saltwater crustaceans (Americamysis bahia). The effects of filtered Aldrich HAs (10–100 mg/L) on organism mortality were determined. Humic acids had no effect on mortality of A. bahia for either pesticide at a salinity of 20%, but greatly reduced the mortality of C. dubia for both pesticides in freshwater (0%). In the latter case, the effect was proportional to the HA concentration. The difference in toxicity mitigation as a function of salinity is believed to be due to conformational changes in the HA molecules, which impact pesticide—HA binding, rather than to organismal effects.