Effects of cadmium on the consumption and absorption rates of a tropical freshwater snail, Radix plicatulus

The effects of cadmium on a freshwater snail, Radix plicatulus, were investigated. The 96-hour LC50 for cadmium was 2.5 mg/L. An increase in cadmium concentrations at sublethal levels results in a significant reduction in the consumption and absorption rates of R. plicatulus. The NOECs and LOECs were 0.15 and 0.20 mg/L for consumption, and 0.10 and 0.15 mg/L for absorption rates. These results suggest that consumption and absorption rates can be useful endpoints in chronic toxicity tests. Moreover, absorption rates should be the preferred endpoint if higher sensitivity is desired, while a test based on consumption rates alone can still be effective as a rapid screening test for aquatic environmental toxicants. The potential use of pulmonate snails as test organisms in ecotoxicological tests is discussed.