上海崇明岛蔬菜地土壤重金属含量与生态风险预警评估

崇明3城镇蔬菜地土壤重金属的总体含量为Cu 29.2 mg·kg^-1、Pb 26.5 mg·kg^-1、Cr 79.4 mg·kg^-1、Zn 91.2 mg·kg^-1和Cd 0.222 mg·kg^-1.除Cd在城桥镇和陈家镇超过国家土壤一级标准(GB 15618-1995)外,其余均低于国家土壤一级标准,并且满足国家对绿色食品产地土壤重金属含量的要求(NY/T391-2000).与上海土壤背景值相比,Cu、Pb、Cr、Zn和Cd分别高出上海土壤背景值 24.3％、24.4％、22.9％、18.8％和65.7％.崇明3城镇蔬菜地土壤重金属生态风险预警评估得出,23个采样点中有3个样点属于中警,10个样点属于轻警,8个样点属于预警,1个样点属于无警,综合评估I_{ER＝1.562,为轻警.3城镇生态风险排序为堡镇（IER=1.799）>城桥镇（IER=1.636）>陈家镇（IER=1.368）,均属于轻警.}

Heavy Metal Content and Ecological Risk Warning Assessment of Vegetable Soils in Chongming Island, Shanghai City

In order to determine the content of copper (Cu), lead (Pb), chromium (Cr), zinc (Zn) and cadmium (Cd) in vegetable field, soil samples were collected from three towns of Chongming Island, an important ecotypic island of Shanghai City. The average content of Cu, Zn, Pb, Cr and Cd in vegetable soil of the three towns is 29.2 mg x kg(-1), 91.2 mg x kg(-1), 26.5 mg x kg(-1), 79.4 mg x kg(-1) and 0.222 mg x kg(-1), respectively. Except for the content of Cd exceeded the first grade of national soil standard (GB 15618-1995), the contents of the other four heavy metals were less than the first grade of the standard, and the content of heavy metals in this fireld met the request of heavy metal level to produce green foods (NY/T 391-2000). The contents of Cu, Pb, Cr, Zn and Cd in the vegetable soils are 24.3%, 24.4%, 22.9%, 18.8% and 65.7% higher than the background value of Shanghai, respectively. The result of ecological risk warning assessment showed that three sampling sites were medium warning situation, ten were light warning situation, eight were warning situation and one was no warning, in all the 23 sampling sites. The total situation of Chongming Island was light warning, and the I(ER) = 1.562. The order of ecological risk was Baozhen town (I(ER) = 1.799) > Chengqiaozhen town (I(ER) = 1.636) > Chenjiazhen (I(ER) = 1.368). The three towns were all light warning situation.