CHLORPYRIFOS TOXICITY STUDIES ON FISH SCALES OF ANABAS TESTUDINEUS

Indiscriminate use of organophosphorus compounds as pesticides is causing a threat to non-target organisms, especially in aquatic environments.The present investigation was to find the chlorpyrifos toxicity effects in scales ofthe edible freshwater fish, Anabastestudineus.  The structural morphology, melanophore index, and decalcification effects were selected for elucidating the toxicity effects in the scales of Anabas. The fish was subjected for a period of 18 days to low dosages (12.5 ppm& 25 ppm) of chlorpyrifosand the changes were observed.The study revealed that exposureto 12.5 ppm and 25 ppm concentrations of chlorpyrifosaltered the scale morphology. The circuli of the scalesof treated fish were observed to be faint, degraded and loosely attached to the underlying skin. A remarkable change observed was the change in color of Anabas testudineus, it became too pale. Chlorpyrifos was found to induce the dispersion of melanophores. The study also revealed an increase in decalcification of the scaleswith the increasing concentration of chlorpyrifos. From the results of the parameters studied it is evident thatchlorpyrifos cause acute toxic effects on Anabastestitudens as early as 18 days of exposure.