珠江口沿岸水域表层沉积物中重金属含量分布及污染评价

Content distribution and pollution assessment on heavy metals in surface sediment from the Pearl River Estuary coastal waters

于2009年对珠江口沿岸水域28个采样站位9种重金属元素的含量与分布进行了研究.使用原子吸收分光光度计分别测定了各采样站位沉积物中的Cu、Fe、Zn、Mn、Ni、Pb、Co、Cr和Cd的含量,并使用标准物作了质量控制.采用多种评价方法对不同环境重金属污染水平及潜在生态风险进行了评价.结果显示,珠江口沿岸水域表层沉积物中Cu、Fe、Zn、Mn、Ni、Pb、Co、Cr和Cd的平均含量分别为17.81～681.11、22 993.58～49 378.76、37.22～286.07、491.57～1 699.63、18.35～57.72、9.81～86.55、11.45～41.53、0.65～21.22、0.15～1.77μg/g(干重).采用海洋沉积物质量标准法结合单因子污染指数法(Pi)评价显示,该海域已受到Cu和Cd污染,其含量均超海洋沉积物一类标准值.结合单元素生态危害因子(Eir)和多元素潜在生态风险指数(RI)的评价显示,Cd和Cu已达到"重"和"严重"危害等级,其潜在生态风险属于"中度"等级.地质累积指数法(Igeo)评价则显示,Cu和Cd分别属"严重"和"中度"污染程度.综合评价表明,珠江口沿岸水域沉积物受Cu和Cd污染较严重,已对海洋环境和沿岸海水养殖造成严重的潜在危害.建议控制养殖区养殖密度,减少网箱数量和人类养殖活动.

Contents and distribution of 9 heavy metals in sediment from 28 sampling sites of the Pearl River Estuary coastal waters in the year 2009 were investigated. Concentrations of copper （ Cu）, iron （ Fe）, zinc （ Zn）, manganese （Mn）, nicke （Ni）, lead （Pb）, cobalt （Co）, chromium （Cr） and cadmium （Cd） in the sediment were measured with a flame atomic absorption spectrophotometer（FAS）. The standard reference material ＂Buffalo River Sediment＂ was also digested and analyzed with ~FAS for quality control. Heavy metal pollution level and potential ecological risk in different environments were evaluated by a variety of evaluation methods. The results showed that the average contents of Cu, Fe, Zn, Mn, Ni, Pb, Co, Cr and Cd in different sampling sites were 17.81 -681. II , 22 993.58 -49 378.76, 37.22-286.07, 491.57 -1 699.63, 18.35 -57.72, 9.81 -86.55, 11.45 -41.53, 0.65 -21.22 and 0.15 -1.77 Ixg/g （dry weight） respectively. Marine sediment quality criteria method combined with the single factor pollution index （Pi） eveluations showed that the sea area has been affected by Cu and Cd pol- lution, both with contents exceeding the criteria of I-class marine sediments. Single element ecological risk factor （Er^i） combined with the muhi-element potential ecological risk index （RI） eveluations showed that Cd and Cu have reached a ＂heavy＂ and ＂serious＂ hazard level, and its potential ecological risk belongs to ＂middle＂ grade. Index of geoaccumulation （Igeo） evaluation showed that Cu and Cd belong to ＂serious＂ and ＂medium＂ pollution degree, respectively. Comprehensive evaluation indicated that Cu and Cd pollution in coastal sediments from the Pearl River Estuary coastal water is relatively serious, and has created serious potential harm to the marine environment and coastal mariculture. We propose to control the breeding density in aquaculture area, reducing the net cage numbers and human mariculture activities.