资源型城市河流无机污染物来源解析及健康风险评价: 以马鞍山市为例

    Source Apportionment of Inorganic Pollutants and Health Risk Assessment in Rivers of Resource-Based Cities: A Case Study of Ma'anshan City

    • 摘要: 矿山开采等人类活动引起的重金属等无机污染物输入, 容易加剧下游城市地表水水质恶化, 造成区域水环境问题, 对美丽城市建设的生态宜居与人体健康具有潜在风险, 特别是金属矿区。研究以典型资源型城市马鞍山市为例, 分析了主要河流采石河和慈湖河水体中无机污染物的分布、来源, 并基于蒙特卡洛模拟评估了潜在健康风险的不确定性。结果表明, 采石河和慈湖河总体污染水平较低, TN和硫酸盐平均超标率分别为35%和74%, 重金属Cu、As和Ni最大检出浓度均小于Ⅲ类水水质标准限值(GB 3838-2002), Hg超过Ⅲ类水质标准的比例达到90%, 是重金属污染指数的主要贡献者。正定矩阵因子分解(PMF)模型划分了5个源, 即冶炼活动源(19.8%)、区域地质环境源(16.5%)、农业活动和城市污水混合源(24.3%)、地质岩层的水-岩相互作用源(19.4%)、农业活动源(20.0%)。相比矿业活动, 应优先考虑农业活动和城市污水的污染防治, 以控制地表水引起的人体健康风险。地表水非致癌健康风险处在可忽略水平, 致癌重金属As是引起人体健康风险的主要因素, 致癌风险不可忽略。成人和儿童的致癌风险值(CR)分别有23%~28%和50%~55%高于可接受阈值10-4, 概率风险较大。持续暴露时间和重金属As浓度对CR的正向贡献率较大。建议将As和Hg作为地表水中溶解态重金属指标监测的重点, 对持续暴露时间和重金属As浓度给予额外关注。

       

      Abstract: Anthropogenic activities such as mining operations have significantly increased the input of inorganic pollutants (e.g., heavy metals) into aquatic environments, exacerbating surface water quality degradation in downstream cities. This has led to regional water environmental issues and poses potential risks to ecological livability and human health in beautiful city construction, particularly in metal-mining areas. Taking the typical resource-based city of Ma'anshan as a case study, this research analyzed the distribution, sources and potential health risks of inorganic pollutants in Caishi River and Cihu River, and evaluated the uncertainty of potential health risks using Monte Carlo simulation. The results indicate relatively low overall pollution levels in both rivers. The average exceedance rates for total nitrogen (TN) and sulfate were 35% and 74%, respectively. The maximum detected concentrations of heavy metals Cu, As and Ni were below the class Ⅲ water quality standards (GB 3838-2002), except for Hg, which exceeded the standards in 90% of samples and became the main contributor to heavy metal pollution indices. The Positive Matrix Factorization (PMF) model identified five sources: smelting activities (19.8%), regional geological environment (16.5%), mixed agricultural activities and urban sewage (24.3%), water-rock interactions from geological strata (19.4%), and agricultural activities (20.0%). For controlling human health risks from surface water, priority should be given to the control of the sources from agricultural activities and urban sewage rather than from mining activities. Non-carcinogenic health risks from surface water exposure were negligible. However, carcinogenic heavy metal As was the main contributor to carcinogenic health risks, which were not negligible. Carcinogenic Risk (CR) values for 23%-28% of adults and and 50%-55% of children exceeded the acceptable threshold of 0.0001 indicating relatively high probabilistic risks. Exposure duration and As concentration were the largest positive contributors to the CR. It is recommended that As and Hg be prioritized as key indicators for monitoring dissolved heavy metals in surface water, with additional attention paid to regulating and managing exposure duration and As concentration for health risks mitigation.

       

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