| 兰州市耕地“五毒”重金属的风险评价与归因分析 |
| 摘要点击 1789 全文点击 531 投稿时间：2021-12-22 修订日期：2022-01-27 |
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| 中文关键词 耕地表层土壤 重金属污染 潜在生态危害 人体健康风险 兰州市 |
| 英文关键词 arable surface soil heavy metal pollution potential ecological hazards human health risks Lanzhou |
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| 中文摘要 |
| 耕地土壤的重金属有可能通过食物链网迁移转化危害生态环境和人体健康.目前，人们对兰州市耕地土壤重金属的生态环境和人体健康风险还不够清楚，从而影响对其有效管控.因此，以兰州市耕地表层土壤为研究对象，采用潜在生态风险危害指数评价As、Cd、Cr、Hg和Pb共5种重金属的生态环境风险，以USEPA提出的健康风险模型和推荐的标准评估其人体健康风险，用地理探测器探究风险空间分异的主要影响因子，以便为研究区重金属污染风险的精准管控提供科学依据.结果表明，研究区耕地表层土壤重金属对生态环境风险主要为中风险（65.25%），少部分为低风险（13.80%）和高风险（20.95%），低风险区主要位于永登县东南部、榆中县中部和北部以及皋兰县西南部；中等风险区在三县五区均有分布；高风险区位于永登县北和东南部、城关区南部、七里河东北部、西固区东部和榆中县中部.5种重金属不同暴露途径的非致癌与致癌风险均为：经口摄入>皮肤接触>呼吸摄入，总体上儿童高于成人.但是，"五毒"重金属的非致癌风险HI均小于1，表明它们对当地居民不存在不可接受的非致癌风险.As的致癌风险分别大于1×10-5（儿童2.04×10-5）和小于1×10-4（成人1.91×10-5），说明其对当地居民存在可接受的中等致癌风险，且儿童的大于成人.地理探测器分析表明，采样季平均降水量对As和Cd人体健康风险空间分异的影响最大，GDP对Cr风险空间分异的影响最大，距铁路距离对Hg和Pb风险空间分异的影响最大；交互作用探测表明，各因子之间均为双因子增强，除主导因子起作用外，pH值、坡度和海拔高度等其它因子也会增强主导因子对耕地土壤重金属风险空间分异的影响程度. |
| 英文摘要 |
| Heavy metals in cultivated soil may migrate and transform through the food chain to harm the ecological environment and human health. At present, the ecological environment and human health risks of heavy metals in cultivated soil in Lanzhou city remain unclear, which impacts the effective management and control of heavy metals. The potential ecological risk hazard index was used to evaluate the ecological environmental risks of As, Cd, Cr, Hg, and Pb in the surface soil of cultivated land in Lanzhou, and the health risk model proposed by USEPA and the recommended standard were used to evaluate their human health risk. The main factors influencing the spatial differentiation of human health risk were explored by using geographic detectors. The risk of heavy metals to the ecological environment of the cultivated land surface soil in the study area was mainly medium (65.25%), and small portions were low (13.80%) and high (20.95%). The low-risk areas were mainly located in the southeast of Yongdeng County, the middle and north of Yuzhong County, and the southwest of Gaolan County. Moderate risk areas were distributed in three counties and five districts. The high-risk areas were located in the north and southeast of Yongdeng County, the south of Chengguan District, the northeast of Qilihe, the east of Xigu District, and the middle of Yuzhong County. The non-carcinogenic and carcinogenic risks of five types of heavy metal exposure pathways were as follows:oral ingestion>skin contact>respiratory ingestion; generally speaking, children were at higher risk than adults. The non-carcinogenic risk in children was higher than that in adults; however, there was no such risk for local residents, as they were all less than 1. At the same time, the carcinogenic risk of As was greater than 1×10-5 (children 2.04×10-5) and less than 1×10-4 (adults 1.91×10-5), respectively. This indicated an acceptable medium risk to the local residents, and the risk to children was again greater than that to adults. Geographical detector analysis showed that average precipitation during the sampling season had the greatest impact on the spatial differentiation of human health risks of As and Cd, GDP had the greatest impact on the spatial differentiation of human health risks of Cr, and distance from the railway had the greatest impact on the spatial differentiation of human health risks of Hg and Pb. Interaction detection showed that all factors were enhanced by double factors. In addition to leading factors, other factors such as pH, slope, and altitude also enhanced the influence of leading factors on the spatial differentiation of heavy metal risk in cultivated soil. |
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