In vivo effects of lead on sea urchin Paracentrotus lividus: toxicity, bioconcentration and oxidative stress response

The current study aims to investigate the median lethal concentration (LC₅₀ at 96 h) of lead for the female sea urchin Paracentrotus lividus. Adult urchins were exposed to six gradually increasing concentrations (0.5, 1, 2, 4, 8 and 10 mg/L) of lead for 96 h. The mortality of the urchins was directly proportional to the lead concentration, and the LC₅₀ value at 96 h was 3.6 mg/L. Additionally, lead concentration and the bioconcentration factor (BCF) in the gonads of control sea urchins and urchins exposed to two selected concentrations (0.5 and 1 mg/L) were determined after 96 h of exposure. The results showed high levels of this metal in the gonads of P. lividus, with BCF values of 35.59 and 92.85 for the two concentrations, respectively. In addition, the effects on non-enzymatic and enzymatic biomarkers, vitellogenin (VTG), glutathione (GSH) and catalase (CAT), were evaluated at baseline (0 h), 24, 48, 72 and 96 h of exposure under laboratory conditions. The results demonstrated significant decreases in CAT activity, as well as in GSH and VTG levels, compared with those of the control. These findings suggest that acute exposure to lead can cause deleterious effects on the survival, reproductive and physiological aspects of P. lividus, which varied depending on the degree of pollution.