海南黎安港表层沉积物重金属分布特征及污染评价

Distribution characteristics and pollution evaluation of heavy metals in the surface sediments of Li'an lagoon, Hainan province

通过对表层沉积物重金属含量测定,探讨海南黎安港内表层沉积物重金属的分布特征、相关性及潜在生态危害程度。结果表明,黎安港表层沉积物中的Cu、Pb、Zn、Cr、Cd、Hg及As含量平均值分别为42.23、17.15、76.58、36.24、0.33、0.040及9.26 mg/kg,重金属含量高值主要位于潟湖中心养殖区域及潟湖北部虾塘养殖沿岸;Cu、Pb、Zn、Hg及As具有相同污染源,主要受养殖影响,Pb、As与Cd还受陆源虾塘影响较大;研究区以中等生态危害为主,其次是强生态危害与轻微生态危害,多种重金属的潜在生态危害指数(RI)高值位于潟湖中心,重金属的潜在生态危害风险大小依次为:Cd>Hg>Cu>As>Pb>Cr>Zn。黎安港与新村港两潟湖重金属在含量分布、潜在生态风险危害存在一定的差异,黎安港以中等生态危害为主,很强生态危害单金属为Cd。

This study investigates the distribution characteristics, correlation, and potential ecological risk of heavy metals in the surface sediments of Li’an lagoon by determining their contents. The results show that the average contents of Cu, Pb, Zn, Cr, Cd, Hg, and As in the surface sediments of Li’an lagoon are 42.23, 17.15, 76.58, 36.24, 0.33, 0.04, and 9.26 mg/kg, respectively, and they are mainly located in the farming area at the lagoon center and the shrimp ponds along the coast. Furthermore, Cu, Pb, Zn, and Hg are the main sources of pollution that affect by aquaculture activities, while Pb, As, and Cd mainly affect terrestrial shrimp ponds. This study also focuses on the ecological risk indexes （RIs）. Different regions had low, medium, or high RIs. The regions with high RIs are mainly at the center of the lagoon. A descending order of the heavy metals with potential ecological risk is Cd〉Hg〉Cu〉 As〉Pb〉Cr〉Zn. The heavy metals distribution and potential ecological risk in Li’an lagoon differ from those in Xincun lagoon. The Li＇an lagoon mainly has a medium ecological risk; however, Cd presents a strong ecological risk.