黔江区农业区域土壤重金属分析及评价

Analysis of heavy metals distribution characteristics and pollution assessment in agricultural region soils of of Qianjiang district in Chongqing

通过对黔江区典型农业耕作区域的土壤中As、Cd、Cr、Cu、Pb、Ni、Zn、Hg重金属进行调查监测,采用单因子污染指数法和综合污染指数法对不同区域和不同土地利用类型的农业土壤进行评价.结果表明：黔江区农业区域土壤pH值范围在4.26～7.82之间,阳离子交换量在10.5 ～ 22.7cmol/kg范围之间,土壤中8种重金属均满足《土壤环境质量标准》（GB15618-1995）中二级标准值限值要求.不同区域和不同土地利用类型的农业土壤中,8种重金属按照国家二级标准评价进行单项污染指数和综合污染指数评价,均属于安全级,处于清洁水平;按照绿色标准评价,处于警戒级别,处于尚清洁水平,基本满足绿色食品产地土壤环境质量要求.

In this work,soil samples were collected from farming areas in Qianjiang district,Chongqing,and the contents of 8 heavy metals were measured.Based on the single factor pollution index and comprehensive pollution index methods,the agricultural soils of different land use type in different areas were studied.The results show：the pH value agricultural soils in Qianjiang district ranges from 4.26 to 7.82,the cation exchange capacity is in the range of 10.5 ～22.7cmol/kg,and the contents of 8 heavy metals are all up to the secondary standard of the Environmental Quality Standards for Soils of China （GB15618-1995）.In addition,in accordance with the secondary standard by the same methods,the 8 heavy metals in the soils belong to the level of security and are at the clean level.However,in terms of the green standard,they are placed on the alert level,which means that they are at the critical level of cleanness,and basically meet the quality requirements of soil environmental in green food producing areas.