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Identification of methyl parathion toxicity in colusa basin drain water
Author(s) -
Finlayson B. J.,
Harrington J. A.,
Fujimura R.,
Isaac G.
Publication year - 1993
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 - 10.1002/etc.5620120212
Subject(s) - cadmium , parathion methyl , parathion , pesticide , environmental chemistry , carbofuran , ecotoxicology , malathion , toxicology , environmental science , fishery , chemistry , biology , ecology , organic chemistry
The cause of toxicity to young striped bass Morone saxatilis and mysids Neomysis mercedis from an agricultural drain (Colusa Basin Drain, Sacramento River Valley, CA) containing tail water from rice fields was investigated. Previous studies had postulated that toxicity was due to one or more of the insecticides carbofuran, malathion, and methyl parathion used on rice in California. The discharge of insecticide‐tainted agricultural drain water into the Sacramento River may have contributed to the decline of the striped bass population in the Sacramento‐San Joaquin Estuary, either directly by mortality or indirectly by reducing food items such as mysids. Trace metals cadmium, copper, and zinc from abandoned mining operations may also have contributed toxicity. Water samples were collected from the Colusa Basin Drain and upstream and downstream from the Sacramento River, analyzed for insecticides and trace metals, and tested for toxicity. No significant toxicity to striped bass was observed for either water body, and no significant toxicity to Neomysis mercedis was observed for the Sacramento River sites. However, Colusa Basin Drain water was significantly toxic to Neomysis mercedis , which was attributed to lethal (up to three times the 96‐h LC50 value) concentrations of methyl parathion. The trace metals, carbofuran, and malathion were present at less than acutely toxic concentrations. The addition of 2 ppt salinity appeared to increase survival of both test organisms. This study clearly demonstrates the need for reducing environmental levels of methyl parathion.