百花湖麦西河口底泥中重金属垂直分布特征及生态危害

为揭示贵阳市百花湖麦西河口不同年代重金属的污染情况,同时为其防治提供科学依据,采用SWB-1型柱状采泥器采集底泥柱状剖面样,选取柱状样界面水澄清及垂直剖面分层清晰完整的底泥柱,研究重金属Hg、Cd、Cu、Zn、Pb、As的垂直分布特征,同时采用潜在生态危害指数法对重金属进行潜在的生态危害评价。结果表明:根据参照标准的不同,不同重金属元素含量超出标准值的大小顺序不同,以土壤环境质量标准作参照,百花湖麦西河口底泥中Hg>Cu>Cd>Zn>As>Pb;以中国湖泊沉积物重金属含量的平均值作参照,Hg>Cu>Zn>As>Cd>Pb;以贵阳市土壤背景值作参照,Hg>Cd>Cu>Zn>Pb>As,其中,Hg污染最严重。重金属Hg含量随深度和年代的变化呈锯齿状多峰分布特征,其他重金属随底泥深度的增加其含量变化相对较为平缓。单一元素潜在生态危害系数顺序Eir为Hg>Cd>Cu>As>Pb>Zn,潜在生态危害指数RI平均值为392.35,达到较强水平。说明,麦西河口底泥中重金属的潜在生态危害程度比较严重。

Vertical Distribution of the Heavy Metals in Maixi River Sediments and Its Potential Ecological Risk

In order to reveal the heavy metal pollution in sediments from Maixi River in Baihua Lake,and provide a scientific basis for the prevention of heavy metals,Vertical distribution and characteristics of heavy metals(Hg,Cd,Cu,Zn,Pb,As) were investigated after collecting columnar sediment samples using SWB-1 bottom sampler.Meanwhile,the potential ecological risk of six heavy metals were assessed with Hakanson pontential ecological risk index.The results showed that the overproof contents of heavy metals were different according to different standards.According to the soil environmental quality standards,the order of heavy metals content arrangement was Hg>Cu>Cd>Zn>As>Pb.Using the average content of heavy metal in sediments of Chinese lakes,the order of arrangement was Hg>Cu>Zn>As> Cd>Pb and according to the soil values of Guiyang City,the order was Hg>Cd>Cu>Zn>Pb>As.Hg pollution was the most serious no matter what standard was used.With the change of the depth and times of the sediments,the vertical distribution characteristics of Hg content increased first and then decreased,but the change of other five heavy metals content was relatively smooth.The order of ecological risk Eir was Hg>Cd>Cu>As>Pb>Zn and RI was 392.35,reaching a high level.All above showed that the degree of the heavy metals potential ecological risk was serious in sediments from Maixi River in Baihua Lake.