于2011年8月采集了珠江口桂山岛海域12个站点的表层沉积物, 对沉积物中重金属的含量进行了测定。结果表明, 桂山岛沉积物中重金属含量与国内外港湾相比属于中等水平, Pb、Cr、Ni、Cu、Zn、Mn平均含量分别为40.06、31.29、14.17、30.67、100.18、599.76 mg/kg。富集系数法和 Hakanson潜在生态风险指数法评价表明:桂山岛沉积物各重金属元素的富集顺序为Cu﹥Pb﹥Zn﹥Mn﹥Cr﹥Ni, 其中Cu、Pb、Zn和Mn富集系数大于1;该海域重金属潜在生态风险总体上处于低水平, 从空间上看, S11危害最为严重。进一步通过主成分分析研究沉积物中重金属的来源, 发现前2个主成分贡献率分别为44.38%、42.61%, 表明重金属主要有2个来源:工业和生活污水排放、岩石的自然风化与侵蚀过程。
Concentrations of heavy metals in surface sediment collected from twelve stations along Guishan Island, the Pearl River Estuary in August were determined. The results indicated that the pollution of heavy metals was at the middle level, and the mean contents of Pb, Cr, Ni, Cu, Zn, Mn, Fe and Ca were 40.06, 31.29, 14.17, 30.67, 100.18, 599.76, 24728.10 and 18677.36 mg/kg, respectively. Accumulating coefficients and potential ecological risk index showed that the sequence of accumulating coefficients of six heavy metals in surface sediment of Guishan Island was Cu﹥Pb﹥Zn﹥Mn﹥Cr﹥Ni, and the coefficients of Cu, Pb, Zn and Mn were higher than 1. The degree of potential ecological risk of heavy metals in this sea area presented a low level, and spatially the most serious one was at station S11. Principal component analysis (PCA) was applied to estimate the sources of heavy metal contamination. Results suggested that the first two components accounted for 44.38% and 42.61% of the total variance, respectively, indicating that industrial and domestic wastewater and erosion of rocks were the main sources of heavy metal contamination.