山东省白马河沿岸耕地表层及剖面重金属和碳、氮含量的空间分布及风险评价

Spatial Distribution and Risk Assessment of Heavy Metal,Carbon and Nitrogen Contents in Cultivated Land Surface and Profile along the Baima River in Shandong Province

本试验以山东省白马河沿岸耕地为研究对象,调查分析各耕地表层及剖面中重金属(Cr、Cu、Mn、Ni、Pb、Zn)含量与碳氮含量的空间分布特征,并采用单因子污染指数(Ei)和潜在生态风险指数(RI)对其进行风险评价。研究结果显示,该区耕地土壤Cr、Cu、Ni、Pb元素含量均低于国家土壤环境质量标准二级标准限制值,有个别剖面Zn元素含量略高,Mn元素低于《农用地土壤环境质量标准(征求意见稿)》标准值;耕地剖面潜在生态风险指数平均值范围在12.97~20.59之间,整体基本处于轻微生态风险水平;耕作层有机碳含量较小,碳氮比介于0.90~12.64范围内且多数在10以下,表明土壤矿化作用强。在治理耕地土壤重金属污染的同时,应注意土壤中各元素含量的均衡,提高耕地土壤生产能力。

Taking the cultivated lands along the Baima River in Shandong Province as the research object,the spatial distribution characteristics of heavy metals(including Cr,Cu,Mn,Ni,Pb,Zn),carbon and nitrogen in the surface and profiles were surveyed and analyzed.Their risks were evaluated by adopting the single factor pollution index(Ei)and potential ecological risk index(RI).The results showed that the contents of Cr,Cu,Ni and Pb in cultivated soil were lower than the second grade standard limit values of the National Soil Environmental Quality Standard.The content of Zn in individual profiles were slightly higher and the content of Mn was lower than the level of the Agricultural Land Soil Environment Quality Standards(Exposure Draft).The potential ecological risk indexes of cultivated land profiles ranged from 12.97 to 20.59,and they were in the slight ecological risk as a whole.The organic carbon content of tilling layer was small.The C/N ratios were in the range of 0.90~12.64 and most were lower than 10,which indicated the strong soil mineralization.In the controll of heavy metal pollution for cultivated land,we should simultaneously pay attention to the balance of elements in soil and improve the productivity of cultivated soil.