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M. Haranadha Reddy ¹, M. Venkata Reddy ¹, K. Radhakrishnaiah ¹

Affiliations
1 Department of Zoology, Sri Krishnadevaraya University, Anantapur-515 055, A.P., IN

Abstract

Small (20±2 g) and large (40±2 g) size groups of the freshwater snail Pila globosa were exposed to different concentrations of nickel (mg/L), and 96 hr LC₅₀ through percent and probit mortality of the animals and also by Dragstead and Behren's method were determined. There was a linear relationship between the percent or probit mortality and the nickel concentration of both the size groups of snails. Thus, the percent and/or probit mortality increased with the increase in concentration of nickel. The percent mortality plotted against log concentration of nickel gave sigmoid curves, whereas the probit mortality plotted against log concentration gave straight lines in both the groups of snails. The 96 hr LC₅₀ obtained for small and large size groups of snails are 117.6 mg/L and 206.3 mg/L respectively. These values obviously indicated a significant (P<0.001) increase in the LC₅₀ of nickel with the increase in the size of the snail. The results of the present study indicate that the small size groups of snails are more sensitive to nickel than the large size groups.

Keywords

Pila globosa, Toxicity Evaluation, Nickel Toxicity, 96 hr LC₅₀.

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