海南岛南部滨海沉积物中重金属分布特征及生态风险评价

通过多种测试手段对海南岛南部滨海地区164个站位表层沉积物样品进行了重金属含量分析，探讨了重金属元素来源及分布特征，并对其生态风险进行了评价，结果表明:研究区Cu、Pb、Zn、Cr、As、Hg和Cd等元素含量分别为10.45、22.38、53.72、23.42、4.52、0.09和0.05 μg/g。重金属元素主要富集在新村港及榆林湾等地，其Hg元素较同类旅游港湾明显偏高。Cu、Pb、Zn、Cr主要来源为自然风化和侵蚀，其含量与分布受粒度制约；As元素分布主要受人类活动影响；有机质降解过程释放的金属离子以及人为因素是Hg、Cd的主要来源。单一重金属污染物对底质环境影响较小，潜在生态危害指数综合评价结果表明，部分站位表层沉积物已经受到重金属污染，各重金属潜在生态危害等级排序依次为Hg＞As＞Cd＞Pb＞Cu＞Cr＞Zn，Hg元素是主要潜在的生态风险，应加强对其监控。

DISTRIBUTION PATTERN OF HEAVY METALS IN THE COASTAL SEDIMENT OF SOUTHERN HAINAN ISLAND AND ECOLOGICAL RISK ASSESSMENT

The southern coast of Hainan Island is a famous tropical beach for tourism. Careful management of environment is required. However, there is lack of ecological risks evaluation in the region for heavy metal contamination. We made a survey and data analysis of heavy metals in the region recently. 164 samples of surface sediments were collected and analyzed, and the distribution patterns, influencing factors and possible ecological risk of heavy metals discussed. The results show that the contents of Cu, Pb, Zn, Cr, As, Hg, Cd are 10.45 μg/g, 22.38 μg/g, 53.72 μg/g, 23.42 μg/g, 4.52 μg/g, 0.09 μg/g, 0.05 μg/g respectively. Heavy metals are enriched in the Yulin Bay and Xincun Harbor. Heavy metals in other areas are relatively low compared to the densely populated harbor areas. Hg is specifically high and increasing in recent years. The contents and distribution of Cu, Pb, Zn, Cr are obviously controlled by grain size. They are mainly from natural weathering and erosion. The distribution of As is affected by human factors, and it is mainly from domestic sewages, fish cage culture, oil seepages and other sources. Hg and Cd owe their origin to degradation of organic matters and human activities. Single metal pollutant has little effect on the environment, but the overall evaluation of potential ecological risk index results indicates that in some of the stations, sediments have been contaminated by multiple heavy metals, for examples, in the Yulin Bay and Xincun Lagoon, due to the impact of sewage discharge. Further control of farming and sewage contaminated areas is required in order to prevent the region from heavy metal pollution.