Comparative Assessment of Cadmium and Copper Toxicity to Physa acuta (Draparnaud, 1805)

Abstract

Cadmium and copper toxicity was investigated using bioassays with neonates of a freshwater gastropod Physa acuta. Mortality, lethal time, and effects on shell length were studied during 28-day chronic exposure experiments. Relative toxicity was assessed from acute and chronic LC values. Copper showed significantly more toxicity at lower concentrations than cadmium (p < 0.001), causing mortality at the same response levels. Conversely, cadmium affected shell length at lower concentrations than copper, although no significant differences (p > 0.05) were found in affected shell length between copper and cadmium at the end of the assays. Lethal time (LT50) was significantly affected by metal concentration (p < 0.001), with a reduction of 8.28% and 5.90% in time per 0.001 mg/L increase of copper and cadmium, respectively. Physa acuta neonates showed medium to high sensitivity to cadmium and copper compared to other freshwater gastropod species, showing it is a suitable test organism, particularly for chronic ecotoxicological assessment.