Ecological and Human Health Risk Assessment of Supratidal Sediments Affected by Legacy Lead Smelting (San Antonio Bay, Argentina)
摘要
This study assesses the ecological and human health risks associated with legacy Pb smelting in San Antonio Bay, Argentina, by evaluating the mobility, bioavailability, and toxicity of potentially toxic elements (PTEs) in contaminated sediments. The methodology included physicochemical characterization (pH, TOC, EC, CaCO3 equivalent, CEC, particle-size distribution, and pseudo-total concentrations of PTEs), selective chemical extractions (water, acetic acid, ammonium acetate, hydroxylammonium chloride, and EDTA), and ecotoxicological assays (seed germination and root elongation of Lactuca sativa L., and heterotrophic respiration). Human health risk was evaluated by calculating carcinogenic and non-carcinogenic risks. Results revealed severe contamination at the affected sites. Mean pseudo-total concentrations in the most polluted samples reached up to 11172 mg kg−1 Zn, 4479 mg kg−1 Pb, 988 mg kg−1 Cu, and 19 mg kg−1 Cd. Selective extractions showed that historical smelting produced PTEs in more mobile and bioavailable forms than those at the reference site, where they occurred mainly in the residual fraction. Zinc and Cd exhibited the highest mobility, reaching up to 2726 and 13 mg kg−1 in soluble fractions, and 5386 and 10 mg kg−1 in exchangeable fractions, respectively. Ecotoxicological tests confirmed high toxicity, with root elongation inhibited by up to 93.5%, strongly correlated with soluble PTEs. Human health risk assessment indicated that non-carcinogenic risk was significant, mainly due to Pb, while Cd posed concern for children. Overall, smelting legacy has created a hazardous environmental hotspot, with the high mobility and toxicity of metals threatening the coastal ecosystem and nearby populations, highlighting the need for remediation.