典型电器工业区河涌沉积物中重金属的分布和潜在生态风险

为了解电子电器制造业聚集区纳污水体沉积物中重金属含量及其潜在的生态风险,对广东佛山市顺德区容桂镇电器工业区河涌沉积物重金属含量进行了空间和垂直分布以及生态风险评估的研究.根据电器制造业分布区域特点,结合河涌水流情况选取12个采样点采集沉积物样品.分析结果表明,内河涌重金属污染状况严重.各监测点元素Cu、Zn、Cr、Pb、As、Cd、Hg的浓度范围分别为70.1～3 525.5、378.1～2 994、130.9～4 791.5、65.8～374.7、19.2～56.8、0.5～4.9、0.3～2.1mg.kg-1.各重金属元素的污染蓄积程度由强至弱依次为:Cd>Cu>Zn>Cr>Hg>Pb>As,其中Cd和Cu的污染蓄积平均指数达到极强程度.重金属在河道中潜在的生态危害由强至弱依次为:Cu>Hg>Cd>Cr>Pb>Zn>As,其中Cu、Hg和Cd平均风险系数达到很强程度,部分监测位点达到极强程度.元素地累积状况和生态风险由下至上垂直分布模式中,Cu、Zn、Pb、Hg和As有逐步减弱趋势,高生态风险元素Cd由下至上从减少到稍有增加,元素Cr则有稳定增加的趋势.

Investigation on the Distribution and Potential Ecological Risk of Heavy Metal in the Sediments from Typical Electrical Industrial Zone

In order to investigate heavy metals contamination status in a river of a typical electrical equipment industrial area, Ronggui, Foshan, 12 sediment simples were sampled for analyzing Cu, Pb, Zn, Cd, Cr, As and Hg. The index of geoaccumulation (I_geo) and potential ecological risk index (PERI) were then employed to evaluate the pollution degree of heavy metals in the sediments. The spatial trends results indicate that the sediments in sampling sites have been severely contaminated and the concentrations of Cu, Pb, Zn, Cd, Ni, Cr, As and Hg in the samples ranged from 70.1-3525.5, 378.1-2994, 130.9-4791.5, 65.8-374.7, 19.2-56.8, 0.5-4.9, 0.3-2.1 mg·kg^-1, respectively. The descending order of pollution degree of metals was: Cd>Cu>Zn>Cr>Hg>Pb>As, and the average I_geo values of Cd and Cu reached severely contamination grade. Similarly, the potential ecological risk intensity caused by different metals was: Cu>Hg>Cd>Cr>Pb>Zn>As, and the average PERI values of Cu, Hg and Cd reached strong grade. Distribution profiles of heavy metals in vertical direction were different with depths. The concentrations of Cu, Zn, Pb, Hg and As reduced from the bottom to the upper layers. The high ecological risk element Cd showed a slight increase in the surface layer, whereas the concentration of Cr steadily increased with the reducing of depth.