| 摘 要： |
An integrated understanding of pollution, environmental risks, and sources of potentially hazardous metals (PHMs) in coastal sediments is essential for protecting and managing the health of coastal ecosystems. Here, we examined the concentrations of 7 PHMs (As, Cd, Cr, Cu, Pb, Hg, and Zn) in surface sediments from a typical bay under long-term human impacts in southern China, to holistically elaborate the pollution characteristics, environmental risks, and sources of PHMs. The results showed that the mean concentrations (mg/kg) were 7.00 (As), 0.164 (Cd), 79.1 (Cr), 29.3 (Cu), 25.4 (Pb), 0.042 (Hg), and 107.4 (Zn), respectively. PHMs in the surface sediments exhibited decreasing trends from the nearshore towards the offshore sea areas, showing high, moderate, and low concentrations in the inner, middle, and outer bay. Geo-accumulation index demonstrated that Cd was the primary polluted metal, followed by Cu, Hg, Zn, Cr, and Pb. Both modified contamination of degree (mCd) and nemerow integrated pollution index (NIPI) indicated that the inner bay was the most polluted area. Potential ecological risk index (PERI) and toxic risk index (TRI) illustrated that PHMs have posed adverse threats on the health of the bay, especially the inner bay. However, PERI suggested that Cd and Hg were the main contributors of the adverse effects, while TRI showed that Cu and Cr were. Principle component analysis suggested that As was from natural sources while other PHMs were derived from anthropogenic sources. Positive matrix factorization model further explained that human activities were the major sources, including industrial and marine transport activities (40.5%) and discharge of domestic sewages (29.3%), while natural sources contributed 30.2%. Based on these findings, useful implications are provided for the prevention and control of PHMs pollution and the implementation of relevant management and remediation strategies in coastal bays. |
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