• Prasanta Mandal
• Dr. Rupa Dasgupta
• Prof. Jayanta Kundu

There is a growing public concern over the potential impact of accumulation of heavy metals in soil. Bioassays can be useful tools to gauge the potential toxicity of contaminants focusing on their bioavailable fraction. The detrivorous soil fauna are ideal model for assessment of soil health. The aim of this study was to determine the toxic effects of lead and cadmium concentrations, administered in the form of lead nitrate [Pb(NO3)2] and cadmium nitrate [Cd(NO3)2] solutions, on Perionyx excavatus by using filter paper contact method under laboratory conditions. Aqueous solutions of various concentrations were prepared by dissolving these test chemicals in deionized water. The concentrations were prepared in mg/ml and the toxicity was measured as μg/cm2.A geometric concentration series of test solution 0.25, 0.5, 1, 2, 4, 8, 16, and 32mg/1ml was prepared and tested.Significant toxic effects and deaths were observed with all tested heavy metal concentrations and were most marked at the concentration: 0.5 mg/1ml for Cd and 4 mg/1ml for Pb in case of P. excavatus. The lethal toxic concentration of Cd and Pb were thus evaluated as 7.15 μg/cm2 and 57.16 μg/cm2 for P.excavatus . Hence the relative toxicity grade were categorized as ‘Extremely toxic’ for Cd and ‘very toxic’ for Pb to P.excavatus . Evaluated results shows that Cd is more toxic than Pb to P.excavatus .

Lead nitrate, Cadmium nitrate, Earthworms, Acute toxicity, Filter paper contact method

"Estimation of toxic effect of lead and cadmium concentration on Perionyx excavatus by using filter paper contact method", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 6, page no.76-79, June 2019, Available :http://www.jetir.org/papers/JETIR1907G53.pdf

"Estimation of toxic effect of lead and cadmium concentration on Perionyx excavatus by using filter paper contact method", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 6, page no. pp76-79, June 2019, Available at : http://www.jetir.org/papers/JETIR1907G53.pdf