Copper and Cadmium Toxicity on Freshwater Snail Physella acuta as Biological Indicator

Abstract

Biological indicators are essential for detecting contaminants globally because they can inform us about the long-term effects of many pollutants in the environment. About 80 snail individuals Physella acuta, an adult freshwater snail (Gastropod: Physidae) were collected from the Tigris River / Lower Zab near Taqtaq bridge, Erbil Province, Iraq on November 2022. In the laboratory, the animals were placed in tanks with river water for acclimatization. The 24-, 48, 72 and 96-h toxicity of two heavy metals cupper and Cadmium (CuSO4·5H2O and CdCl2.2 H2O) have been investigated using various nominal concentrations, including 0.0, 0.3, 0.5, 0.7 and 0.9 mg L−1 for Cu and 0.5, 1.0,3.0 ,5.0 and 7.0 mg L−1 for Cd. The behavioral changes and the snail’s mortality were noticed daily and the median lethal concentrations values (LC50) for 24-, 48-, 72- and 96-h were calculated. The LC50 values for the 24, 48,72 and 96- hour exposures to Cu and Cd were 0.911, 0.699, 0.462, 0.209 mg L−1 and 2.359, 1.020, 0.094 and 0.040 mg L−1, respectively. Results indicated that Cu showed noticeably greater toxicity than Cd. Also, treated groups showing significant variation in water pH value throughout the studied time. The study concluded that selected snail species can be used as a bioindicator for evaluating the hazards related to environmental pollutants.

Keywords

• bioindicator
• cupper
• cadmium
• freshwater snail
• toxicity