黄河小浪底水库地表水中重金属的时空变化与概率健康风险

Spatio-temporal Variation and Probability Health Risk of Heavy Metals in Surface Water of Xiaolangdi Reservoir in the Yellow River

小浪底水库地表水重金属污染是我国黄河流域水安全的一个重要问题.2014~2022年期间,调查了6种重金属(Cu、Zn、Pb、As、Hg和Cd)的时空分布并采用重金属污染指数、内梅罗指数和污染程度对其污染水平进行评价.结果表明,重金属污染水平较低(HPI平均值为18.15),符合地表水Ⅲ类水质阈值.6种重金属检出率为91.6%~92.9%,浓度中值范围为0.020(Hg)~1.850(As)μg·L^(-1).呈现出丰水期浓度低于平枯水期,下游断面浓度较高,且在过去的9 a呈现下降趋势的时空特征.重金属污染主要来源于工农业生产和人为排放.此外,结果发现TN、高锰酸盐指数和NH_(4)^(+)-N与重金属浓度有很强的相关性(P<0.05),这表明水中重金属的迁移、转化和吸附沉降可能受到相关因素的影响.敏感性分析表明,金属浓度(贡献率为56.56%~92.27%)是重金属健康风险评估的主要影响因素.此外,虽然重金属暴露不会对人体造成不良影响,但在极端条件下实际风险可能较高.总之,研究对公共健康和环境管理都有潜在的应用价值.

Heavy metal pollution in the surface water of Xiaolangdi Reservoir is an important problem regarding water security in the Yellow River Basin in China.From 2014 to 2022,the spatio-temporal distribution of six heavy metals(Cu,Zn,Pb,As,Hg,and Cd)were investigated,and their pollution levels were evaluated by using the heavy metal pollution index(HPI),Nemerow index(NI),and contamination degree(CD).The results showed that the pollution level of heavy metals in surface water was low(mean HPI=18.15),which met the national surface water quality thresholdⅢ.The detection rates of the six heavy metals ranged from 91.6%to 92.9%,and the median concentration ranged from 0.020(Hg)to 1.850(As)µg·L^(-1).This showed that the concentration in the flood season was lower than that in the dry season,the concentration in the downstream section was higher,and it showed a downward trend over the past nine years.Heavy metal pollution in the water mainly came from industrial and agricultural production and human emissions.In addition,we found that TN,permanganate index,and NH_(4)^(+)-N were strongly correlated with the concentration of heavy metals(P<0.05),which indicated that the migration,transformation,adsorption,and sedimentation of heavy metals in the water might be affected by related factors.Sensitivity analysis showed that the metal concentration(with contribution rates of 56.56%-92.27%)was the main influencing factor of heavy metal probabilistic health risk assessment.In addition,although heavy metal exposure would not cause adverse effects on the human body,the actual risk may have been higher under extreme conditions.In summary,this study has potential application value for public health and environmental management.