TISSUE LIPID-LEVELS OF THE CLAM, VILLORITA CYPRENOIDES VAR COCHINENSIS, FOLLOWING EXPOSURE TO ENDOSULFAN, MALATHION, AND METHYL PARATHION

Sublethal stress of toxicants on organisms is generally measured throu gh metabolic changes. The effects of three pesticides (endosulfan, mal athion, and methyl parathion) on tissue lipid levels in the estuarine bivalve, Villorita cyprenoids var. cochinensis, have been measured. Th e reduction in lipid content was expressed as a function of the pestic ide concentrations and the duration of the exposure periods (24, 48, 7 2, and 96 h). The results point to the existence of a direct relations hip between the applied stress and the fall in the lipid content. The order of toxicity was endosulfan > malathion > methyl parathion. The d epletion in lipid content observed may reflect an adaptive response of the organism to pesticide stress. Thus lipids in bivalves have been s hown to be an important reserve material that may be utilized under st ressed conditions as an energy source. (C) 1995 by John Wiley & Sons, Inc.