湘南某典型冶炼区大气沉降重金属分布特征及健康风险评价

Distribution characteristics and health risk assessment of heavy metals in atmospheric deposition from a typical smelting area in southern Hunan Province

  • 摘要: 为研究冶炼区大气沉降中重金属元素分布特征及健康风险,在湘南某冶炼厂的主导风方向下风方向按距离由近到远依次设置5个采样点(分别标记为点位1~点位5),为期1年(2023年4月—2024年4月)收集大气沉降样品,测定9种重金属的大气沉降通量及浓度,并评估其健康风险。结果表明:该冶炼区大气沉降中Pb、Zn的平均沉降通量输入高于其他元素,分别为24.58和20.72 g/hm2,各重金属平均浓度顺序为Pb>Zn>As>Mn>Ni>Cu>Sb>Cd>Cr;大气沉降中重金属浓度和通量随距离增加呈递减趋势,表明冶炼活动为大气沉降的主要污染源。非致癌风险中,As的非致癌风险系数最高(5.53×10−3),但低于1.0,表明这9种重金属均不存在非致癌健康风险或者风险较低,且儿童非致癌风险商值普遍高于成人,表明儿童易受到更大的健康风险。致癌风险中,As的总致癌风险系数最大(1.66×10−7),但未超过10−6,表明该冶炼区致癌风险较小。建议在湘南冶炼区域建立大气沉降重金属动态监测体系,尤其要优先管控As污染源,以期准确评估重金属的潜在健康威胁。

     

    Abstract: To study the distribution characteristics and health risk of heavy metals in atmospheric deposition in a typical smelting area, five sampling sites were set up downwind of prevailing wind direction from a smelting plant in southern Hunan Province, arranged by distance from near to far (Sites 1 to 5). Over a period of one year (April 2023 to April 2024), atmospheric deposition samples were collected and the concentrations and the atmospheric deposition fluxes of nine heavy metals in those samples were analyzed. The health risks of these metals were also assessed. The results showed that Pb and Zn had the highest average deposition fluxes among the heavy metals, at 24.58 and 20.72 g/hm2, respectively. The average concentrations of heavy metals decreased in the order of Pb>Zn>As>Mn>Ni>Cu>Sb>Cd >Cr. The concentrations and flux of heavy metals in atmospheric deposition decreased with increasing distance, indicating that smelting activities were the main source of atmospheric deposition. In terms of non-carcinogenic risks, the non-carcinogenic risk coefficient (HI) of arsenic (As) was the highest at 5.53×10−3, but it was below 1.0, indicating that none of these nine heavy metals posed non-carcinogenic health risks or the risks were relatively low. Additionally, the HQ values for children were generally higher than those for adults, suggesting that children were more vulnerable to their health effects. Regarding carcinogenic risks, the total carcinogenic risk coefficient of arsenic (As) was the largest at 1.66×10−7, which did not exceed 10−6, indicating that the carcinogenic risk was minimal in this smelting area. Therefore, the study recommended establishing a dynamic monitoring system for atmospheric deposition of heavy metals in the southern Hunan smelting area, with the priority given to controlling As pollution sources, to accurately assess the potential health risks of heavy metals in atmospheric deposition.

     

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