Bioaccumulation of trace metals and health risk assessment in Commerson's dolphins, Cephalorhynchus commersonii, from the Southwestern Atlantic

Abstract

Marine mammals, particularly odontocetes, are essential indicators of marine ecosystem health and are significantly impacted by environmental pollutants. This study examines the accumulation of essential and toxic trace metals in the liver and kidney tissues of Commerson´s dolphins (16 females and 13 males) bycaught in Tierra del Fuego, Argentina. Essential metals like copper (Cu), iron (Fe), zinc (Zn), and manganese (Mn) were detected in all samples, with Fe showing the highest concentration. Non-essential elements, particularly cadmium (Cd) and lead (Pb), were also detected. Chromium (Cr) was below detection limits in all samples. Cd concentrations exceeded unhealthy limits in some individuals, while Pb concentrations fell within subclinical effect thresholds, although no related symptoms were observed. Statistical analysis showed higher concentrations of Cu, Zn, and Cd in sexually mature dolphins, with no significant sex-related differences. Positive correlations between biological variables and trace metal concentrations in both organs were found. Overall, the findings underscore the role of Commerson´s dolphins as bioindicators for monitoring marine pollution and its potential risks to human health, particularly highlighting the importance of considering sexual maturity and biological variables in assessments of metal accumulation.