Faculty of Agriculture and Natural Resource, Ardakan University, Ardakan, Iran.
Faculty of Natural Resources, University of Tehran, Tehran, Iran.
Environ Geochem Health. 2021 Sep;43(9):3469-3484. doi: 10.1007/s10653-021-00844-y. Epub 2021 Feb 9.
Heavy metal pollution significantly reduces the quality of the environment and threatens human health, especially in industrial cities. This study investigated toxic metals concentrations, pollution levels and human health risks assessment of urban soils in Yazd City, as an industrial city in center of Iran. Soil surface samples (0-10 cm) were collected from 30 points in the area for geochemical analysis. The concentrations of heavy metals were determined using an inductively coupled plasma mass spectrometry (ICP-MS). The values of the mean concentrations of toxic metals (mg kg) in the urban soils decrease in the order of Zn (83.9) > Pb (34.5) > Cr (32.6) > Cu (23.5) > Ni (23.4) > As (5.86) > Co (4.86) > Cd (0.27). The mean concentration of Zn, Pb, As and Cd elements was higher than the background and the crust values. A pollution assessment by Geo-accumulation Index (I), Pollution Index (PI), Contamination Degree (C), the Integrated Pollution Index (IPI), the Pollution Load Index (PLI) and Integrated Nemerow Pollution Index (INPI) showed that As, Cd and Pb were moderately enriched and the study area polluted considerably by these toxic metals. Based on PI results, 88.9% of the urban soil samples highly polluted by As. Overall, the quality of the urban soil in Yazd City is clearly affected by toxic metals. Due to the prevailing wind direction, the route of the north-south highway of Iran and the population density and traffic of the northwestern and southern areas of the study area were found the highest level of pollution indicators (IPI > 1.8; LPI > 1.3; C > 15 and INPI > 4.3). The results of Pearson correlation analysis indicated that all pollution evaluation indicators were influenced by As and Cu, and showed high significant correlation with these two elements, while neither of them had a significant relationship with Pb and was found also a weak link statistically with Cd. Health risk assessment of toxic metals has been performed in both carcinogenic and non-carcinogenic sectors. The results indicate that oral intake is the main pathway that toxic metals can harm human health for both the child and adults. The carcinogenic risks (RI) of adults and child by toxic metals were as follows: Ni > Pb > Cr > As > Cd. Hazard quotients (HQ) and hazard index (HI) values for child also were higher than these for adults. Generally, the results demonstrated that the potential carcinogenic health risks for adults of toxic metals were in an acceptable range in study area, whereas for Cr, Ni and Pb with RI > 10, the risk of cancer in child probably increases.
重金属污染严重降低了环境质量，威胁人类健康，尤其是在工业城市。本研究调查了伊朗中部工业城市亚兹德市城区土壤中的有毒金属浓度、污染水平和人体健康风险评估。从该地区 30 个点采集了土壤表层样品（0-10 厘米）进行地球化学分析。使用电感耦合等离子体质谱法（ICP-MS）测定重金属浓度。城市土壤中有毒金属的平均浓度（mg kg）按 Zn（83.9）> Pb（34.5）> Cr（32.6）> Cu（23.5）> Ni（23.4）> As（5.86）> Co（4.86）> Cd（0.27）的顺序递减。Zn、Pb、As 和 Cd 元素的平均浓度高于背景值和地壳值。通过地质累积指数（I）、污染指数（PI）、污染程度（C）、综合污染指数（IPI）、污染负荷指数（PLI）和综合内梅罗污染指数（INPI）进行污染评估表明，As、Cd 和 Pb 中度富集，研究区受这些有毒金属污染相当严重。根据 PI 结果，88.9%的城市土壤样品受到 As 的高度污染。总体而言，亚兹德市城区土壤质量明显受到有毒金属的影响。由于盛行风向、伊朗南北高速公路路线以及研究区西北部和南部的人口密度和交通流量，发现污染指标（IPI>1.8；LPI>1.3；C>15 和 INPI>4.3）达到最高水平。Pearson 相关分析结果表明，所有污染评价指标均受 As 和 Cu 的影响，与这两种元素高度显著相关，而与 Pb 无显著关系，与 Cd 也仅存在统计学上的弱关系。已对有毒金属的致癌和非致癌部分进行了健康风险评估。结果表明，对于儿童和成人，口服摄入是有毒金属危害人体健康的主要途径。成人和儿童的有毒金属致癌风险（RI）如下：Ni> Pb> Cr> As> Cd。儿童的危害商数（HQ）和危害指数（HI）值也高于成人。总体而言，结果表明研究区成人有毒金属的潜在致癌健康风险处于可接受范围内，而对于 Cr、Ni 和 Pb，RI>10，儿童患癌症的风险可能会增加。
