重庆市某典型区域土壤和水稻中重金属含量跟踪验证研究

Study on Tracking and Verification of Heavy Metal Content in Soil and Rice in A Typical Area of Chongqing

分别在2018年和2019年对重庆市某典型区域土壤和水稻中重金属进行了采样检测,对两年调查结果进行了对比。结果表明:土壤理化性质的相对偏差(或绝对差)合格率高,两年的调查结果无显著差异。土壤中重金属含量的相对偏差合格率为16.7%~100%;两年土壤中镉的环境质量结论不一致,其余重金属的环境质量结论一致;土壤中镉、铬、镍、铜、锌、铅和砷的两年调查数据存在显著差异。水稻糙米中重金属含量的相对偏差合格率为0.0%~100%;两年水稻糙米中各项重金属超过污染物限量的比例相差较大;水稻糙米中镉、锌和砷两年的调查数据存在显著差异。以上结果说明,土壤重金属含量,特别是水稻糙米中的重金属含量并不稳定,一次调查结果不能作为评价某区域土壤和水稻中重金属含量是否超标的依据,应对调查区域进行长期跟踪调查。

Samples of heavy metals in soil and rice in a typical area of Chongqing were taken in 2018 and 2019 respectively,and the results of the two-year investigation were compared.The results showed that the relative deviation(or absolute difference)acceptance rate of physical and chemical properties in soil was high,and there was no significant difference between the two-year investigation results.The acceptance rate of relative deviation of heavy metal content in soil was 16.7%~100%.The conclusion of environmental quality of cadmium in soil in two years was inconsistent,while the conclusion of environmental quality of other heavy metals was consistent.There were significant differences among soil cadmium,chromium,nickel,copper,zinc,lead and arsenic for two years.The acceptance rate of relative deviation of heavy metal content in brown rice was 0.0%~100%.The proportion of each heavy metal in brown rice exceeding the pollutant limit in two years were different greatly.There were significant differences among cadmium,zinc and arsenic in brown rice for two years.The above results indicated that the content of heavy metals in soil,especially in brown rice was not stable,and the results of one survey could not be used as the basis for evaluating whether the heavy metals in soil and rice in a certain region exceed the standard,so a long-term follow-up survey should be conducted in the surveyed region.