连云港市水稻主产区土壤和灌溉水重金属含量分析及在稻米中的累积效应

Analysis on soil and water heavy metal content and accumulation effect in rice grains in major rice producing areas in Lianyungang

对连云港市水稻主产区的土壤、灌溉水和稻米中重金属含量进行了测定。研究结果表明:(1)该地区水稻灌溉水所含重金属污染较轻,没有对稻米品质造成影响,完全符合无公害稻米生产要求。(2)土壤中砷、铅、镉的平均含量超过国家和江苏省背景值,砷、镉、铬、铅和汞的单项污染指数P<1,污染分担率排序为砷(42.56%)>镉(37.00%)>铬(7.78%)>铅(7.22%)>汞(5.54%),土壤主要以砷、镉污染为主;综合污染指数P综=0.59<0.7,属1级,为安全清洁水平,符合无公害农产品生产基地重金属环境质量要求。(3)稻米中4种重金属污染排序为铅>汞>镉>砷,以铅和汞污染为主;除铅外,稻米中重金属富集效应不明显,徐稻3号累积铅的能力较强,稻米中镉的含量与土壤中pH值存在着负相关关系。

Heavy metal content of soil, irrigation water and rice grains were measured in major rice producing areas in Lianyun- gang, the results were as follows. （ 1 ） Heavy metal content of irrigation water was low in the area, had no effects on the rice quali- ty and was quite up to production requirement of green rice. （2） The average content of arsenic （As） plumbum （Pb） cadmium （Cd） in soil all exceeded background values of the Nation and Jiangsu province. Single pollution indexes （PS） of As, Pb, Cd, chromium and mercury were below 1, pollution share rate was arranged as follows： As （42.56%） 〉 Cd （37.00%） 〉 chromi- um （7.78%） 〉 Pb （7.22%） 〉 mercury （5.54%） and As ＆ Cd were the two major pollution resources. Comprehensive pollution index （PC） -- 0.59 〈 0.7, belonging to first grade and clean and safe level, and was quite up to production requirement of green rice. （3） Arrangement of 4 heavy metals in rice grains was as follows： Pb 〉 mercury 〉 Cd 〉 As and Pb ＆ mercury were the two major pollution resources. Accumulation effect of heavy metal in rice grains was not clear except Pb, Xudao 3 accumulated more Pb in its grains. There was negative relationship between Cd content in rice grains and pH value in soil.