Preliminary toxicity assessment of chromium (Cr) and lead (Pb) on terrestrial snail (Helix aspersa)

Abstract

Chromium and lead are among the major toxicants that have their own environmental concerns and are very harmful for living organisms even in small concentrations. The present study is performed to evaluate the acute toxicity potential of chromium and lead on terrestrial garden snail (Helix aspersa) at different concentration ranges from 1.0 mg/L to 20 mg/L at different exposure time. In determining acute toxicity, LC₅₀ values after 24, 48, 72 and 96 h for both the metals were determined by probit statistical analysis method. Graphs also plotted between percent mortality and used concentrations to obtain regression equation and R² values. The obtained median lethal concentration (LC₅₀) for chromium were 15.13 mg/L, 12.88 mg/L, 6.76 mg/L and 4.027 mg/L for 24, 48, 72 and 96 h period of exposure, respectively. Similarly, for lead obtained LC₅₀ values were 15.282 mg/L, 6.095 mg/L, 2.094 mg/L and 1.352 mg/L for 24, 48, 72 and 96 h period of exposure, respectively. The study signifies the role of these metals in causing metal stress which leads to variation in electrolytes and A/G (Albumin to Globulin) ratio. The analysis of obtained results revealed that chromium is less toxic to H. aspersa in comparison to lead at similar concentrations and exposure time. It is concluded that the present study is one of its own kind of approach which may contribute in developing standard protocols for determining preliminary toxicity assessment of different heavy metals.