曲靖市周边稻田土壤-籽粒中Pb、Cd、Cu和Zn的风险评价

Risk Assessment of Pb,Cd,Cu and Zn in Farmland and Rice System Around Qujing City

农田重金属污染导致的粮食安全已危机到人类健康,对农田重金属污染迁移累积到可食部分的风险评价亟待解决。本文研究对象为云南省曲靖市富源县黄泥河镇五乐滇东电厂附近的上评子、城里头、姜家扎外和普祥四个样品区域的土壤-籽粒,实验分别采集了土壤和水稻籽粒样品,测定了土壤和水稻籽粒中Pb、Cd、Cu、Zn的含量,对土壤及水稻籽粒中Pb、Cd、Cu、Zn进行单因子和综合污染指数评价。结果表明:上评子和城里头采样区综合生态风险指数分别为201.26和153.3,达到中等生态危害,而姜家扎外和普祥采样区土壤达到轻微生态危害。在上评子、城里头和普祥的采样点实验结果表明,水稻籽粒中构成重度污染的为Pb和Cd,构成轻度污染的为Zn,Cu未造成污染。而姜家扎外采样点水稻籽粒中构成重度污染的为Pb和Cd,Cu和Zn未达到污染水平。研究区域Cd为主要污染元素,达到重度污染,而Pb、Cu、Zn的Pi值<1,不能构成污染。通过对土壤-水稻籽粒的污染指数进行综合评价得出:该研究区域水稻的重金属污染综合指数都达到了重度污染水平。

Food security is threatened by heavy metal contamination in farmland,posing risks to human health.Urgent efforts are needed to assess migration of heavy metal pollutants in farmland and their accumulation in edible parts of crops.This study focuses on soil and rice samples collected from four sample locations near Wule Diandong Power Plant in Huangnihe Town,Fuyuan County,Yunnan Province,namely,Shanglezi,Chenglitou,Jiangjiazawai and Puxiang.The concentrations of Pb,Cd,Cu,and Zn were determined in both soil and rice grain samples.The single factor and comprehensive pollution index of Pb,Cd,Cu,and Zn in the soil and rice grains were evaluated.The results showed that the comprehensive ecological risk indexes for Shangpingzi and Chengtou were 201.26 and 153.3,respectively,indicating a medium level of ecological damage.Conversely,the soil in Jiangjiazhawai and Puxiang was slightly damaged.Analysis of rice grain samples from Shangpingzi,Chengtou,and Puxiang revealed heavy pollution of Pb and Cd,with Zn showing light pollution,and Cu not reaching pollution levels.However,the most serious pollutant in the rice grains were Pb and Cd,while Cu and Zn did not reach the pollution level.Cd was the main pollution element in the study area and reached the level of severe pollution.Pi value of Pb,Cu and Zn was less than 1,which did not constitute pollution.According to the comprehensive evaluation of the pollution index of soil rice grain,the comprehensive index of heavy metal pollution of rice in the study area has reached the level of heavy pollution.