黄河三角洲表层土壤重金属空间分布与潜在生态风险评价

Distribution and Potential Ecological Risk Assessment of Heavy Metals in the Topsoil of the Yellow River Delta

研究黄河三角洲表层土壤中重金属空间分布特征,评价其潜在生态风险。结果表明:表层土壤(0-20 cm)Cu、Zn、Cr、Cd、Pb、Ni、As和Hg的平均含量为27.87,79.19,69.01,0.383,21.98,33.42,13.76,0.025 mg/kg。除Cd外,其他重金属含量平均值均小于国家二级标准值;各重金属空间分布均呈现自西北向东南递减的趋势,且实验区含量最高,核心区含量最小;Hakanson潜在生态风险指数评价表明,Cd为中等-较强生态危害,其余重金属单项均为轻微生态危害,潜在风险程度由高到低依次为Cd>Hg>As>Ni>Cu>Pb>Cr>Zn;保护区综合潜在生态风险为轻微-中等生态危害,呈实验区>缓冲区>核心区的规律。重金属受人类活动影响较大,距离人类活动较近区域含量高,较远区域含量低。

The distribution and potential ecological risk of heavy metals in the topsoil(0-20 cm) of the Yellow River Delta were investigated. The results showed that the average contents of Cu, Zn, Cr, Cd, Pb, Ni, As and Hg in the topsoil were 27.87, 79.19, 69.01, 0.383, 21.98, 33.42, 13.76 and 0.025 mg/kg, respectively, and these values were all less than the national standard value II, except the content of Cd. The spatial distribution of above heavy metals decreased from northwest to southeast, and the highest content was found in experimental zone, while the lowest was found in core area. The evaluation of potential ecological risk index of Hakasnon showed that Cd was medium-strong ecological hazard, and the other heavy metals were minor ecological hazards, the potential risks of the different heavy metals followed the order of Cd>Hg>As>Ni>Cu>Pb>Cr>Zn. The comprehensive potential ecological risk of the protected area was minor to moderate ecological hazard, and the ecological hazard level of each functional area was experimental zone>buffer zone>core zone. Heavy metals were greatly affected by human activities, which were higher in areas close to human activities and lower in distant areas.