Distribution, pollution, and human health risks of persistent and potentially toxic elements in the sediments around Hainan Island, China.

Human activities have changed the global concentration of potentially toxic elements (PTEs) and significantly altered the marine ecosystem. Little is known about the concentrations of these PTEs around Hainan Island in China, or their distribution and human health risks. Understanding the variability of PTEs in marine sediments and how they accumulate is important not only for biodiversity and ecological conservation, but also for management of aquatic natural resources and human health risk assessments. This study showed that the concentrations of six PTEs (Cd, Cu, Zn, As, Pb, and Hg), sampled in nine different cities, were linked to human activities. In order to understand the ecological risks associated with PTE pollution, we calculated the contamination factor (CF), enrichment factor (EF), pollution load index (PLI), and geo-accumulation index (Igeo) of each element in each city. These indicators suggest that the pollution of Cd and Zn in the sediments of these cities is higher than that of the other PTEs. We also carried out a human health risk assessment which demonstrated the carcinogenic effects of Zn on children and adults in ChengMai, while Pb showed non-carcinogenic effects at all the studied sites, suggesting that Zn pollution in the sediments of ChengMai may pose human health risks. We would therefore advise that follow-up studies endeavor to monitor the levels of PTEs in the flora and fauna of these cities.