广东沿海沉积物重金属含量及风险评价

Contents and risk assessment of heavy metal sediments in Guangdong coastal areas

通过收集大量监测资料,研究广东省沿海沉积物重金属污染特征及生态风险评价.基于社会、经济、自然等方面,分析广东省沿海沉积物重金属的主要影响因素.结果表明,珠江口海域沉积物中重金属含量高于粤东、粤西区域,其中Cu(106.98±70.69μg/g)、Pb含量(65.74±65.03μg/g)分别以广州、深圳最高,Zn(250.25±55.01μg/g)、Cd(1.48±0.30μg/g)、Cr(96.48±9.79μg/g)、As(17.30±14.00μg/g)含量均为中山最高.Hakanson潜在生态风险评价结果显示,广东沿海各单项指数(0.528±0.377～2.107±3.665)及综合指数(7.135±7.880)均处于"低等"水平.单因素生态风险评价结果为:Cd>Cu>Pb>Zn>As>Cr,而生态风险综合指数则表现为:珠江口(12.131)>粤东(5.488)>粤西(4.1560).沿海沉积物中Cu、Pb、Zn、Cd、Cr之间均具显著正相关性(P<0.05),说明各重金属污染来源相近,具有同源性;部分重金属(Cu、Pb、Zn)含量与TOC显著正相关(P<0.05),而部分重金属(Cu、Cr、Cd)含量与pH值显著负相关(P<0.05).

The data of heavy metal content in sediments of costal area of Guangdong Province were collected and its ecological risks were assessed using the Hakanson’s potential ecological risk index.Based on social,economic and natural aspects,the major factors affecting the heavy metals content were investigated.Results showed that the contents of various heavy metals in sediments of Pearl River Estuary were significantly higher than that of the eastern or western coastal regions of Guangdong.The highest contents of Cu(106.98±70.69μg/g)and Pb(65.74±65.03μg/g)were recorded in Guangzhou and Shenzhen among all the coastal areas,whereas the highest contents of Zn(250.25±55.01μg/g),Cd(1.48±0.30μg/g),Cr(96.48±9.79μg/g)and As(17.30±14.00μg/g)were recorded in Zhongshan.Hakanson potential ecological risk assessment showed that the individual index(0.528±0.377~2.107±3.665)and the comprehensive index(7.135±7.880)of Guangdong coast were overall low.The results from single factor ecological risk assessment indicated that the order of ecological risk for the six heavy metals was Cd>Cu>Pb>Zn>As>Cr,and the order of ecological risk index was the Pearl River Estuary(12.131)>eastern coastal regions of Guangdong(5.488)>western coastal regions of Guangdong(4.1560).Significant correlations were found between the contents of Cu,Pb,Zn,Cd and Cr in the sediments(P<0.05),indicating the homologous sources.The contents of Cu,Pb and Zn in sediments were positively correlated with TOC(P<0.05),while the contents of Cu,Cr and Cd in sediments were negatively correlated with pH values(P<0.05).