剑河县水田及旱地土壤重金属污染特征与评价

Characteristics and Assessment of Heavy Metal Pollution in Paddy Field and Arid Land in Jianhe County

探讨剑河县内某水田及旱地土壤中重金属对人体健康影响程度。通过对两种不同用地土壤中重金属测定值与贵州省重金属背景值进行比较,采用改进灰色聚类法对水田及旱地土壤中重金属污染进行评价,并利用健康风险评价探讨两种用地土壤中重金属对附近人群健康影响程度。结果显示,与贵州省土壤背景值相比,水田及旱地土壤中重金属存在超标现象,较为严重的分别是Pb和As。与国家标准GB15618—1995《土壤环境质量标准》相比较,水田土壤重金属符合1级,旱地土壤重金属符合2级。水田及旱地土壤重金属对儿童威胁较大,前者总非致癌风险顺序为As>Cr>Pb>Cd>Ni>Zn>Cu,后者则是As>Cr>Pb>Ni>Cu>Zn>Cd。改进灰色聚类法评价的结果显示,水田土壤无明显重金属污染,旱地土壤重金属属于轻度污染。手—口途径是土壤重金属为最主要的暴露途径,儿童因土壤重金属摄入而带来的健康风险均高于成年人,应给予儿童群体更多的关注。

Effects of heavy metals in soil of paddy field and arid land in Jianhe County,Guizhou Province on human health were studied.The measured values of heavy metals in two different type soils were compared with background values of heavy metals in Guizhou Province.Pollution of heavy metals in soils from two different type lands was evaluated by modified grey clustering method.Impacts of heavy metals in soils from different type lands on health of local population were explored by health risk assessment.The results show that heavy metals in paddy field and arid land soils exceed the background values of soil in Guizhou Province,and the most severe ones are Pb and As.Compared with national standard GB 15618-1995,the heavy metals in paddy soils meet the limits of Grade 1,and that in arid soils meet Grade 2.Heavy metals in soils of paddy field and arid land are more dangerous to children.Total non-carcinogenic risk of the former is As>Cr>Pb>Cd>Ni>Zn>Cu,and the latter is As>Cr>Pb>Ni>Cu>Zn>Cd.The results from improved grey clustering method show that there is no obvious pollution of studied heavy metals in paddy field and heavy metal pollution in arid land is mild.Contaminated hand-mouth pathway is the most important way to expose heavy metals in soil.Children's health risk caused by heavy metals intake in soil is higher than adults,so more attention should be paid to children.