安全利用区和严格管控区稻米重金属健康风险评价

Health risk assessment of heavy metals pollution in rice produced in safe utilization areas and strictly controlled areas

为了解广西某重要粮食产区重金属污染情况及其稻米的健康风险,协同采集该区域33对土壤表层样品和稻米样品,测定土壤和稻米中Cd、Hg、As、Pb和Cr含量并协同划分土壤环境质量类别,采用健康风险模型评价安全利用区和严格管控区稻米对儿童和成人的健康风险。结果表明:该区域农田土壤超过《土壤环境质量农用地土壤污染风险管控标准(试行)》(GB 15618—2018)筛选值的重金属元素为Cd和As,Cd和As超过筛选值的点位占比分别为60.61%和12.12%,Cd超过管制值的点位占比为36.36%,其他元素均未超过筛选值;稻米中仅元素Cd超过标准限值(0.2 mg·kg^(-1)),超标率为39.39%。调查区域优先保护类、安全利用类和严格管控类农田土壤面积占比分别为22.51%、40.69%和36.80%。安全利用区和严格管控区的稻米对儿童和成人均存在非致癌和致癌健康风险,且严格管控区稻米的非致癌和致癌健康风险均高于安全利用区稻米,严格管控区稻米的平均非致癌风险指数和致癌风险指数分别是安全利用区稻米的4.44倍和3.74倍,其中安全利用区稻米的健康风险主要来源于Cd,严格管控区稻米的健康风险则来源于Cd和As。针对安全利用区农田需要采取如水分管理、种植低累积品种和施用钝化剂等措施降低稻米Cd的健康风险,而严格管控区农田则需进行种植结构调整,从而保障当地居民身体健康。

In this study,to investigate heavy metals pollution and health risk of rice produced in an important grain-producing area in Guangxi,33 pairs of soil and rice samples were collected to determine the contents of Cd,Hg,As,Pb,and Cr,and the environmental quality of farmland was classified.The health risk model was used to evaluate the health risk of rice in safe utilization areas and strictly controlled areas to children and adults.The results showed that only the contents of Cd and As in soil exceeded the screening value.The proportion of Cd and As super-screening values was 60.61%and 12.12%,respectively,and 36.36%of soil samples exceeded the control value of Cd.Furthermore,only the Cd content of rice samples exceeded the standard limit(0.2 mg·kg^(-1)),and standard-exceeding rate was 39.39%.The priority protection,safe utilization,and strictly controlled category accounted for 22.51%,40.69%and 36.80%,respectively,of the surveyed area.Rice in both safe utilization areas and strictly controlled areas all had non-carcinogenic and carcinogenic health risks for children and adults,and all of them in strictly controlled areas were higher than in safe utilization areas.The average non-carcinogenic risk index and carcinogenic risk index of strictly controlled areas were 4.44 times and 3.74 times respectively.Compared to the safe utilization areas,the health risks of rice in safe utilization areas mainly arose from Cd,whereas they were from Cd and As in strictly controlled areas.In the safe utilization areas,measures such as water management,low accumulation varieties,and application of passivators should be taken to reduce the health risk of Cd in rice,while in the strictly controlled areas,planting structure should be adjusted to safeguard the health of residents.