Toxicity of cadmium chloride (CdCl₂) in Phorcus lineatus: Effects on survival, mobility and hemocyte parameters

This study aims to evaluate, under controlled conditions, the acute toxicity of cadmium chloride (CdCl₂) in the marine gastropod Phorcus lineatus. Specimens sampled from Morocco's Atlantic coast were exposed to different concentrations of CdCl₂ for 96 h, with two replicates for each tested concentration. Survival and mobility were assessed at 24, 48, 72, and 96 h of exposure. The effect of CdCl₂ on total hemocytes number (THN) and hemocyte size were also evaluated. The results showed a significant decrease in survival and mobility with increasing CdCl₂ concentration and exposure duration. The median lethal concentration (LC₅₀) at 96 h was estimated at 6.04 mg L^-1 CdCl₂ (95% confidence interval: 4.91-7.41 mg L^-1), corresponding to 2.97 mg L^-1 Cd. Exposure to the contaminant induced a significant reduction in the size of hyalinocytes and their nuclei in animals treated with concentrations ≥5 mg L^-1, whereas granulocytes and undifferentiated cells showed no significant effects. In gastropods exposed to low CdCl₂ concentrations (≤ 5 mg L^-1), THN increased significantly with exposure time. However, it decreased in individuals treated at 20 mg L^-1, suggesting an immunotoxic effect of CdCl₂.