基于蒙特卡洛模拟的兰州银滩湿地公园沉积物重金属污染特征及风险评价

Characteristics and risk assessment of heavy metals contamination in sediments from the Lanzhou Yintan wetland park based on Monte Carlo simulation model

为探究兰州市市区湿地沉积物重金属污染状况及潜在生态风险和健康风险,以兰州银滩湿地公园为研究区,采集并分析了40个表层沉积物样品重金属As、Cd、Cr、Cu、Hg、Ni、Pb和Zn的含量.采用蒙特卡洛模拟与地累积指数(Igeo)、富集因子(EF)、综合生态风险指数(NIRI)和人体健康风险评价模型相耦合的方法分别对沉积物重金属污染特征、综合生态风险和人体健康风险进行定量评估.结果表明,沉积物重金属平均含量除Cd、Pb和Hg之外,其他元素含量均值均低于甘肃省土壤背景值,地累积指数和富集因子显示,沉积物以Cd污染为主,Pb和Hg次之,其余5种重金属均为无污染;综合生态风险指数表明,研究区沉积物的主要生态危害元素是Cd,且Cd对综合生态危害指数的贡献值达到了93.60%,其余元素均为低风险;健康风险评估结果显示,研究区沉积物重金属对不同人群均存在非致癌与致癌健康风险,其中对成人男性、成人女性和儿童构成非致癌风险的概率分别为:16.1%、18.3%和6.0%,Cd和Cr为主要的非致癌风险污染物;对成人男性、成人女性和儿童造成致癌暴露风险的概率分别为:8.0%、13.2%和98.1%,As和Cr为主要的致癌风险污染物.

To investigate the contamination status,potential ecological and health risks associated with heavy metals in sediment in the urban wetland of Lanzhou city.A total of 40 surface sediment samples were collected from Lanzhou Yintan wetland park and analyzed for the concentrations of As,Cd,Cr,Cu,Hg,Ni,Pb,and Zn.A combination of geoaccumulation index(Igeo),enrichment factor(EF),Nemerow integrated risk index(NIRI),and a health risk assessment model coupled with Monte Carlo simulation was employed to quantitatively assess the characteristics,comprehensive ecological and human health risks of heavy metals contamination in sediments.The results showed that the mean concentrations of heavy metals in sediments were generally lower than their soil background values of Gansu Province except for Cd,Pb,and Hg.The pollution indices of Igeo and EF indicated that the sediments were mainly contaminated by Cd,followed by Pb and Hg,while the other five heavy metals were not found to be significantly contaminated.The NIRI revealed that the survey region was primarily driven by Hg,which contributed 93.60%to the comprehensive ecological hazard index.Moreover,the ecological risks associated with As,Cd,Cr,Cu,Ni,Pb,and Zn were found to be low.Health risk assessment indicated that heavy metals in sediments posed noncarcinogenic and carcinogenic risks to all populations.The probabilities of noncarcinogenic risks were 16.1%,18.3%,and 6.0%for adult males,adult females,and children,respectively,with Cd and Cr identified as the main noncarcinogenic risk metals.For carcinogenic risks,the probabilities were 8.1%,13.2%,and 98.1%for adult males,adult females,and children,respectively,with As and Cr identified as the main carcinogenic risk metals.