汉江上游汉中段河流表层沉积物重金属污染风险评价

通过监测汉江上游汉中段河流表层沉积物重金属Pb,Cu,Zn,Cd,Cr的浓度,分析了各元素的含量分布特征,并选用Hakanson生态风险指数法对研究区进行了环境风险评价。结果表明,汉江上游汉中段各监测点重金属富集顺序为:Cd >Zn >Pb >Cr >Cu。单个重金属的污染指数C_fⁱ显示,汉江上游汉中段监测点仅有Cu的含量均值为0.83,小于1,为轻微污染;Pb,Zn,Cd,Cr的均值分别为1.06,1.25,1.33,1.02,略大于等于1,处于轻微污染以上水平,达到中度污染水平。综合分析多项重金属污染系数C_d,单项重金属的潜在生态风险系数E_rⁱ和多种重金属的生态系统的潜在生态风险指数I_R可知,汉江上游汉中段各监测点沉积物重金属污染属于轻微生态危害。

Risk Assessment of Heavy Metal Pollution in Surficial Sediments from Hanjiang Upstream Section of Hanzhong City

Based on observating the concentration data of heavy metals including Pb, Cu, Zn, Cd and Cr in the surficial sediments from the Hanjiang upstream, and the data of the content of each heavy metal distribution characteristics, the potential ecological risk of heavy metals in research area were analyzed and assessed by the method of potential ecological risk indices presented by Hakanson. The results indicated that the accumulating order for these heavy metals were Cd >Zn >Pb >Cr >Cu. The single pollution mean coefficient of Pb, Cu, Zn, Cd, Cr were 1.06, 0.83, 1.25, 1.33, 1.02, respectively. Among which, only Cu was less than 1, indicating slight pollution. The other elements were greater than or equal to 1, indicating moderate pollution. Combining with the heavy metal pollution coefficient(C_d), heavy metal potential ecological risk coefficient E_rⁱ and the potential ecological risk index(I_R) of surficial sediments from Hanjiang River, the contamination level of surficial sediments in Hanjiang upstream was slight ecological risk.