Acute toxicity evaluation of chlorpyrifos on earthworm Megascolex konkanensis (Fedarb, 1898) by a simple paper contact method
The study was carriedout on the acute toxicity of chlorpyrifos on earthworm Megascolex konkanensis (Fedarb,1898) by a simple paper contact method. The filter paper contact test was performed for earthworm acute toxicity assessment based on OECD guidelines 207. The test substance chlorpyrifos is dissolved in acetone to give a range of known concentrations. The Whatsman No.1 filter paper of diameter 10cm was placed in 10 cm petridish. 1% of toxic test solution was prepared from selected pesticide. Test substance of desired concentration is pipetted into each petridish. The petriplates were incubated in the dark at room temperature for 48hrs. At the end of 48hrs mortality was recorded. The dose response test always included a control organism which is treated with acetone. 1% solution of Chloropyrifos sprayed in 10 set of petriplates and each set contain two number of earthworm. Therefore 0.7ml concentration of test solution showed very toxic to earthworm. Some clinical signs like pinching off coiling, curling and mucus secretion were observed.