Ye Mai, Zhang Jing-Ru, Zhang Lu-Lu, Li Zhao-Hui, Li Xing-Yuan, Zhou Yong-Zhang
Guangdong Provincial Academy of Environmental Sciences, Guangzhou 510045, China.
Guangdong Provincial Key Laboratory of Geological Process and Mineral Resources Exploration, Sun Yat-sen University, Guangzhou 510275, China.
Huan Jing Ke Xue. 2020 Dec 8;41(12):5579-5588. doi: 10.13227/j.hjkx.202005053.
In order to reveal the transfer factor and perform health risk assessments of heavy metals in soil-crop systems in the high incidence area of nasopharyngeal carcinoma (NPC) in Guangdong province of China, the farmland system of Sihui City in the high incidence area of NPC was selected as the research object, and rice, lettuce, and corresponding soil samples were collected. As, Cu, Hg, Mn, Ni, Pb, and Cd in the soil and crop samples were analyzed. Based on the contents and chemical forms of seven heavy metals, the environmental pollution, bioavailability, and transfer factors of heavy metals in the soil-crop system were assessed using statistical analyses, pollution index evaluations, and transfer factor methods, and the health risks of adults and children in the study area were assessed using the health risk assessment model recommended by the U.S. Environmental Protection Agency. The results showed that the farmland soil in the study area was basically clean (=0.43); Cd and Mn mainly existed in a bioavailable state, Hg mainly existed in a potentially available state, and As Cu, Ni, and Pb mainly existed in a residual state. The lettuce was safe (=0.48), while the pollution index of rice (=7.66) was higher than that of lettuce, and the main polluting element was Pb (PI=10.25). The results of soil pollution assessments are not completely consistent with those of crop pollution assessments, so they should be combined with the bioavailability of heavy metals and crop effects for correlation analyses. Cd and Cu are more easily absorbed by lettuce, while Cd, Cu, and As are more easily enriched by rice. Special attention should be paid to Cd and Cu pollution in farmland soils, and As pollution should be of focus in paddy fields. In the study area, the non-carcinogenic risk index (HI) value of edible lettuce for adults and children was less than 1 and the average value of the total carcinogenic risk index (Risk) of edible lettuce was less than 1×10. Therefore, the health risk of edible local lettuce was within the acceptable range. The average HI index of rice for adults and children was more than 1 and the main non-carcinogenic factor was Pb; the risk index of rice was more than 1×10, and the main carcinogenic factor was As. Rice consumption in the study area will cause certain health risks, and the threat to adults is greater than that to children. Therefore, As in rice may be related to the high incidence of NPC in Sihui City. It is suggested that the remediation of heavy metals in farmland soils be strengthened or that residents be forbidden to plant or eat local rice and other crops with greater health risks.
为揭示中国广东省鼻咽癌（NPC）高发区土壤 - 作物系统中重金属的迁移因子并进行健康风险评估，选取NPC高发区四会市的农田系统作为研究对象，采集水稻、生菜及相应土壤样本。分析土壤和作物样本中的砷（As）、铜（Cu）、汞（Hg）、锰（Mn）、镍（Ni）、铅（Pb）和镉（Cd）。基于七种重金属的含量和化学形态，采用统计分析、污染指数评价和迁移因子方法评估土壤 - 作物系统中重金属的环境污染、生物有效性和迁移因子，并使用美国环境保护局推荐的健康风险评估模型评估研究区域内成人和儿童的健康风险。结果表明，研究区域的农田土壤基本清洁（=0.43）；镉（Cd）和锰（Mn）主要以生物可利用态存在，汞（Hg）主要以潜在可利用态存在，而砷（As）、铜（Cu）、镍（Ni）和铅（Pb）主要以残留态存在。生菜安全（=0.48），而水稻的污染指数（=7.66）高于生菜，主要污染元素为铅（PI = 10.25）。土壤污染评估结果与作物污染评估结果不完全一致，因此应结合重金属的生物有效性和作物效应进行相关性分析。镉（Cd）和铜（Cu）更容易被生菜吸收，而镉（Cd）、铜（Cu）和砷（As）更容易在水稻中富集。应特别关注农田土壤中的镉（Cd）和铜（Cu）污染，并将砷（As）污染作为稻田的重点关注对象。在研究区域，食用生菜对成人和儿童的非致癌风险指数（HI）值均小于1且食用生菜的总致癌风险指数（Risk）平均值小于1×10。因此，食用当地生菜的健康风险在可接受范围内。成人和儿童食用水稻的HI指数平均值均大于1，主要非致癌因子为铅（Pb）；水稻的风险指数大于1×10，主要致癌因子为砷（As）。研究区域内食用水稻会造成一定的健康风险，对成人的威胁大于儿童。因此，水稻中的砷（As）可能与四会市NPC的高发有关。建议加强农田土壤重金属修复或禁止居民种植或食用当地水稻及其他健康风险较大的作物。
