福建省西南近岸海域表层沉积物重金属污染特征与风险评价

Pollution characteristics and risk assessment of heavy metals in sediments in the coastal areas of southwest Fujian

  • 摘要: 于2020年8月对福建省西南(闽西南)近岸海域表层沉积物中7种主要重金属的污染特征和来源进行了调查研究,并采用Hakanson潜在生态风险指数法、地累积指数法和富集因子法对调查海域重金属的潜在生态风险进行了评价。结果表明:调查海域表层沉积物中Hg、Cd、As、Cr含量符合国家第一类海洋沉积物质量标准,而Pb、Cu和Zn含量较高,分别有11.8%、23.5%和17.6%的站位超过第一类海洋沉积物质量标准,但符合第二类海洋沉积物质量标准,沉积物环境质量良好;7种重金属含量均与有机碳(TOC)含量、粒度呈显著相关性,而与硫化物含量无相关性;调查海域表层沉积物中Cu、Zn、Pb、As具有相似来源,呈现农业、交通和水土流失复合污染的特征,而Hg和Cd主要来源于工业污染;3种生态风险评价方法得出的结果基本一致,重金属单因子生态风险系数为Hg>Pb>As>Cd>Cu>Cr>Zn,调查海域生态风险总体上处于低生态风险水平,但仍然建议重点控制Hg和Pb污染。

     

    Abstract: In order to understand the pollution characteristics of heavy metals in surface sediments of the coastal waters of southwest Fujian, the distributions and potential sources of seven major heavy metals (Cu、Zn、Pb、Cd、Cr、Hg and As) in the surface sediments were investigated in 2020. Furthermore, the Hakanson's potential ecological risk index, geo-accumulation index and enrichment factor were used to evaluate the potential ecological risk of these heavy metals. The results showed that the content of Cd, Cr, Hg and As in the surface sediments were less than those documented by the China's national first-class benchmark (CFCB) of marine sediment quality standards.However, it was found that in some monitored stations, the heavy metal content was higher than those of CFCB quality standard, accounting for 11.8% (Pb), 23.5% (Cu) and 17.6% (Zn), respectively, but less than those documented by the China’s national second-class benchmark (CSCB). All these results indicated that the environmental quality of sediments in the coastal waters of southwest Fujian is good. The contents of the selected metals were significantly correlated with TOC content and particle size, but had not correlationwith sulfide content. The sources of Cu, Zn, Pb and As in the surface sediments of the sea area were similar, and they exhibited the characteristics of compound pollution from agriculture, transportation and soil erosion, while Hg and Cd mainly came from industrial pollution. Based on three methods of ecological risk assessment, which was the Hakanson's potential ecological risk index, geo-accumulation index and enrichment factor, their results were consistent. The single-factor potential ecological risk of these heavy metals in sediments followed the order: Hg>Pb>As>Cd>Cu>Cr>Zn. In conclusion, the potential ecological risk of the study area is at a low level on the whole, but it is still recommended to focus on the control of Hg and Pb pollution.

     

/

返回文章
返回