琼海市水稻土重金属污染现状及评价

在琼海市12个乡镇的典型土壤中采集21个混合土壤样本，并对各土壤样本中重金属元素Hg、Cd、Cr、Pb和As的含量进行测定，以了解琼海市水稻土重金属含量及污染现状。依据国家土壤环境质量二级标准，采用单项污染指数法以及内梅罗综合污染指数法评价土壤中重金属的污染程度。结果表明：琼海市水稻土各重金属元素的平均含量均小于二级标准值；表层土壤Pb和Hg、Pb和Cd、As和Cd、As和Pb之间存在显著相关性(P＜0.01)；从单项污染指数来看，除了大路镇存在Cr元素轻度污染外，其他各乡镇均未受到重金属Hg、Cd、Cr、Pb和As的污染；从全市范围来看，仅有大路镇为警戒级程度，其他11个乡镇安全清洁，全市的综合污染指数仅为0.32，说明全市水稻土环境质量状况整体清洁，处于安全水平。

Status and Evaluation of Heavy Metals Pollution in Paddy Soil of Qionghai Ciy

In order to investigate the condition of heavy metals in paddy soil of Qionghai City, 21 mixed soil samples were collected in typical soils of 12 villages and towns , and their contents of Hg, Cd, Cr, Pb and As were detected. According to the second class standard of the national soil environmental quality, pollution severity of heavy metals in the soil was evaluated by monomial pollution index method and Nemerow synthetic pollution index method. The results show that the Qionghai paddy soil all the average contents of heavy metal elements are less than the secondary standard; Surface soil Pb and Hg, Pb and Cd, As and Cd, As and Pb between significant correlation (P<0.01); From the point of monomial pollution index, in addition to Cr element existing light pollution in Dalu town, other villages and towns are not subjected to heavy metal Hg, Cd, Cr, Pb and As pollution; From the city's perspective, only the Dalu town to alert level degree, other villages and towns belong to safe levels, the city's synthetic pollution index was only 0.32, indicating that overall cleanliness of the city's paddy soil and at a safe level.