太湖地区某地农田土壤及农产品中重金属污染及风险评价

对江苏省太湖地区某冶炼厂周围的稻田、菜地土壤及水稻等17种农产品中的Pb、Cd、Hg、As、Cu、Zn、Ni、Cr、Se等9种重金属元素进行采样分析,参照<国家土壤环境质量二级标准>和<食品中重金属限量卫生标准>进行评价,同时,依据美国联邦环境保护署推荐的RfD值和我国居民平均食物消费结构评估了农产品对当地人群的重金属暴露风险.结果显示,供试稻田土和菜地土中的重金属Cd、Pb污染严重;农产品样品中Cd、Pb含量全部超过国家食品中重金属限量卫生标准,且Cd、Pb、As对人群的暴露风险系数甚高.17种农产品中,对重金属富集能力最强的是茼蒿、空心菜、菠菜等茎叶类蔬菜,它们不适宜在该地种植.研究表明,在局部范围内,点源污染可能带来土壤环境的重金属污染及农产品重金属食物安全问题.

Pollution and risk evaluation of heavy metals in soil and agro-products from an area in the Taihu Lake region

The present paper has done a detailed analysis to the samples collected from the soil and farm produce from a polluted farmland near a smelter in the Taihu Lake area with the respective contents of Pb,Cd,Hg,As,Cu,Zn,Ni,Cr and Se analysed in 2005.The pollution situation of the soil and farm produce has been assessed with the national background and guideline values of State Environmental Quality Category II,and by the values of the State Food Security Standard.And,finally,a general assessment of the exposure level by the food and drinking intake of the produce from the polluted and is given,while taking into account the R_fD values recommended by USEPA(2000).The results of the analysis indicate that the contents of the 8 metals both of the paddy and vegetable lands proved much higher than those stipulated in the National Background Standards in the area and the Nemeiro Indices detected indicated a heavy compound pollution of the multiple heavy metals,with Pb,Cd being most heavily polluted.Among the 9 metals of the samples,Pb and Cd were far above the State Food Guideline limits.Of all the farm produce,the metal contents of stem and leaf vegetables of crowndaisy,water spinach and cole reached the dangerous metal-content allowable levels.Thus,serious health risks are highly likely to get exposed to for the local people through their drinking and eating of the above-said farm produce,especially in case of potentially intense exposure to Cd,Pb and As.Therefore,serious concerns may arise as to the soil environmental pollution and health hazards due to the serious metal-pollutes soil in the Taihu Lake area.