| 摘要: |
| 为查明德阳绵竹市某磷石膏堆场周边土壤及农作物重金属污染情况，确定治理优先权，对堆场周边土壤、水稻协同采样并测定分析，利用健康风险评价模型，分析磷石膏堆场周边水稻土污染特征、稻米中重金属累积特征及食用风险，并进行人体健康风险评价。结果表明：磷石膏堆场周边土壤和稻米中重金属含量均与采样点和尾矿中心距离负相关，距离越近重金属含量越高。堆场周围200 m范围内土壤综合污染指数小于1，为警戒范畴；100 m、50 m范围内，为轻度污染，其中50 m范围内Cd、As分别超过《土壤环境质量 农用地土壤污染风险管控标准（试行）》（GB 15618—2018）所规定筛选值的1.15倍、0.14倍。距堆场50 m处，稻米中的As、Pb含量均严重超标。根据稻米重金属的人体健康风险评价结果，在磷石膏堆场周围200 m范围内，稻米中重金属的非致癌风险大于1，对儿童和成人都存在着明显的非致癌健康影响，各重金属非致癌风险表现为Pb＞As＞Zn＞Cd。稻米中Cd与As的致癌风险超过可接受水平，其中Cd为主要的致癌因子。稻米中重金属元素之间为正相关性，存在着几种重金属的复合污染，协同作用明显。在磷石膏堆场200 m范围内，应加强对土壤风险管控，保证粮食安全和人体健康安全。 |
| 关键词: 土壤 稻米 重金属 健康风险评价 |
| DOI：10.7515/JEE202029 |
| CSTR： |
| 分类号: |
| 基金项目:中国地质调查局地质调查项目（DD20189501） |
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| Status of heavy metal pollution in paddy soil and human health risk assessment of rice around phosphogypsum yard |
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LAN Yushu, SHI Guqi, YANG Gang, SI Yiyang, CHENG Rong
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1. Collage of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China
2. Institute of Ecological and Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China
3. Institute of Comprehensive Utilization of Mineral Resources, China Academy of Geosciences, Chengdu 610041, China
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| Abstract: |
| Background, aim, and scope Deyang, Sichuan Province, is rich in mineral resources and has a history of phosphorus chemical industry more than 60 years, it is one of the most important phosphorus industrial bases in China. Phosphogypsum, as a by-product in the process of wet phosphoric acid production, is one of the largest industrial solid wastes in China. Since phosphogypsum contain certain heavy metals, the stacking of these phosphogypsum could increase the concentrations of heavy metals in soil via leaching and weathering, thus cause ecological risks. Furthermore, soil heavy metals can be taken up by rice and result in adverse effects on human health via the food chain. Therefore, the bioavailability of these heavy metals and the concentrations of heavy metals in rice are of great concern. Materials and methods The soil and rice samples around the storage yard were collected to analyze the heavy metal content, and then health risk evaluation model was used to analyze the characteristics of heavy metal pollution. Results (1) The comprehensive soil pollution index within 200 m of the phosphogypsum stacking yard is less than 1, which is a warning category. The soil within 100 m and 50 m of the phosphogypsum stacking yard is mild pollution. However, the concentrations of Cd and As in the soil within 50 m are 1.15 and 0.14 times higher than the warning level, respectively, setting by the Ministry of Ecology and Environment of the People’s Republic of China (Soil environmental quality: risk control standard for soil contamination of agricultural land, GB 15618—2018). The As and Pb concentrations in rice samples within 50 m of the phosphogypsum stacking yard exceeded the threshold limit. (2) The non-carcinogenic risk of heavy metals in rice samples within 200 m of the phosphogypsum stacking yard was greater than 1, with the non-carcinogenic risk in different metals in an order of Pb＞As＞Zn＞Cd. (3) The carcinogenic risk of Cd and As in rice exceeded the threshold limit, and Cd is the predominant carcinogenic factor. (4) There is a positive correlation among heavy metals in rice, showing synergistic effect. Discussion The content of heavy metals in the soil and rice around the phosphogypsum yard is negatively correlated with the sampling distance, the closer the distance, the higher the heavy metal content. Pb and As are the dominant contributors to the non-carcinogenic risk. Since children are lighter in weight and have a higher risk of exposure through ingestion, the non-carcinogenic health risk of children is greater than that of adults. The carcinogenic risk values of Cd and As were higher than the threshold values, suggesting a certain carcinogenic risk. Conclusions The results showed that the soil and rice samples within 200 m of the phosphogypsum stacking yard had potential environmental risks. Recommendations and perspectives Safe disposal of rice within 200 m of the phosphogypsum stacking yard is required to minimize the associated environmental risks and ensure food security. |
| Key words: soil rice heavy metal health risk assessment |
