The contamination of urban soils with heavy elements due to the rapid development of urbanization and urban services has become a major environmental and human health challenge. This study provides insight into the urbanization controls on combined pollution severity and health risk potential of heavy metals in corn-cultivated urban versus non-urban soils. A multifaceted assessment was conducted using enrichment factor (EF), ecological risk (ER), bioconcentration factor (BCF), transmission factor (TF), hazard index (HI), and carcinogenic risk (CR). The results indicate a significant increase in the concentration of all metals in urban farmlands. When compared to the non-urban soils, EF implies a significant increase of all metals in the urban soil, downgrading this index from minimal enrichment (EF < 2) in the control soils to moderate enrichment (2 ≤ EF < 5) in the urban soils. Likewise, the average ER value showed an increase in the urban soils than in the control soils in the order of Fluvisols (66.6%) > Regosols (66.1%) > Cambisols (59.8%) > Calcisols (47%). The BCF and TF values for different elements decreased in the order of Cd (0.41-0.92) > Cu (0.1-0.23) > Zn (0.1-0.18) > Ni (0.01-0.03) > Pb (0.005-0.011) and Zn (0.75-0.94) > Cu (0.72-0.85) > Pb (0.09-0.63) > Cd (0.17-0.22) > Ni (0.01-0.21), respectively, which indicates that certain metals were not mobilized to the extent that they had been accumulated in the plant roots. The total carcinogenic risk was ranged from 5.88E-05 to 1.17E-04 for children and from 1.17E-04 to 2.30E-04 for adults, which implies a greater associated health risk for children.© 2022. The Author(s).

Contamination with the eight elements, Hg, As, Cr, Cu, Ni, Pb, Zn, and Cd, is a serious concern in Zhongshan, which is a typical light industrial city, China. 60 surface soil samples were collected to investigate the concentrations, spatial distribution, human health risk, and sources of these elements in the soils in Zhongshan. The concentrations of the eight elements were analyzed while using ordinary kriging analysis, pollution load index (PLI), potential ecological risk index (RI), human health risk, correlation analysis, and factor analysis. The mean concentrations of the tested elements, excluding Pb and As, were higher than the soil background values in the Pearl River Delta. The spatial distribution of the tested elements revealed a zonal distribution pattern and high values in several areas. The mean PLI and RI indicated slight and moderate risk levels. Health risk assessment demonstrates that both children and adults were more exposed to Cu than to Cr, As, and Cd. However, the associated carcinogenic risk is acceptable. Hg that originated from human activities; As, Cr, Cu, Ni, and Cd originated from industrial activities; and, Pb and Zn originated from transportation activities. Cd was the main pollutant in the study area and it was present at higher concentrations when compared with those of the other elements. Therefore, Zhongshan should encourage enterprises to conduct industrial transformation to control the ecological risk.

Accumulations of heavy metals in urban soils are highly spatial heterogeneity and affected by multiple factors including soil properties, land use and pattern, population and climatic conditions. We studied accumulation risks of Cd, Cu, Pb and Zn in unban soils of Beijing and their influencing based on the regression tree analysis and a GIS-based overlay model. Result shows that Zinc causes the most extensive soil pollution and Cu result in the most acute soil pollution. The soil's organic carbon content and CEC and population growth are the most significant factors affecting heavy metal accumulation. Other influence factors in land use pattern, urban landscape, and wind speed also contributed, but less pronounced. The soils in areas with higher degree of urbanization and surrounded by intense vehicular traffics have higher accumulation risk of Cd, Cu, Pb, and Zn. Copyright © 2015 Elsevier Ltd. All rights reserved.

In order to study the pollution, ecological risk and health risk of heavy metals and risk elements\nin the surface farmland of the cold black soil area in Northeast China, the main grain production area\nin China, based on the collection and analysis of samples in 2010 and 2021, the soil heavy metals\nand risk element in this area were assessed by using the method of Geo accumulation index (Igeo),\npotential ecological hazard index (RI) and health risk assessment (HRA) model. The results show that\nthere are heavy metals and risk element pollution in the soil, which is accumulated year by year. The\naverage contents of Hg, Cd, Cr, Ni, Pb, Zn, As and Cu in the soil in this area are higher than the\nbackground values of Qianjin town. The heavy metals and risk element in the black soil and farmland\nin the cold area are obviously affected by human activities. There are different degrees of regional\nvariability, and the coefficient of variation of Hg is 79%; Some elements have ecological risk, and Hg\nand Cd are the main influencing elements of soil ecological risk in shallow farmland; Heavy metals\nand risk element have non-carcinogenic health risks to children. The carcinogenic risk index of adults\nand children exceeded the soil treatment benchmark value of 10^-6 proposed by EPA, As is the element\nthat contributes the most to non-carcinogenic health risk and carcinogenic health risk in adults and\nchildren. In view of the continuous accumulation of heavy metals and risk element in farmland soil,\nit is necessary to improve ideological understanding, improve laws and regulations, formulate norms and standards, develop methods and technologies, and scientifically prevent and control heavy metals\nand risk element pollution.

In this study, the concentrations of potentially toxic elements in 283 topsoil samples were determined. Håkanson toxicity response coefficient modified matter element extension model was introduced to evaluate the soil elements contamination, and the results were compared with the pollution index method. The sources and spatial distribution of soil elements were analyzed by the combination of the PMF model and IDW interpolation. The results are as follows, 1: The concentration distribution of potentially toxic elements is different in space. Higher concentrations were found in the vicinity of the mining area and farmland. 2: The weight of all elements has changed significantly. The evaluation result of the matter-element extension model shows that 68.55% of the topsoil in the study area is clean soil, and Hg is the main contamination element. The evaluation result is roughly the same as that of the pollution index method, indicating that the evaluation result of the matter-element extension model with modified is accurate and reasonable. 3: Potentially toxic elements mainly come from the mixed sources of atmospheric sedimentation and agricultural activities (22.59%), the mixed sources of agricultural activities and mining (20.26%), the mixed sources of traffic activities, nature and mining (36.30%), the mixed sources of pesticide use and soil parent material (20.85%).

To understand the status of soil heavy metal pollution and its impact on human health, the Rucun\narea of Wutai County, Xinzhou City, Shanxi Province, was selected as the research area. Using SPSS19\nstatistical software, the land accumulation index method, potential ecological hazard index method, and\nhealth risk assessment model were used to evaluate the degree of soil heavy metal pollution, ecological\nrisk, and health risk in the area. The results indicate that the degree of heavy metal pollution in the\nsoil of the study area is relatively low, and there are light pollution points for As and Pb; The degree\nof ecological risk is relatively low; As, Cr, and Pb elements pose a significant non carcinogenic health\nthreat; As and Cd elements pose a risk of carcinogenesis; The average value of the total cancer risk\nindex is between 10^-6 a nd 10^-4, which does not pose significant harm to the physical health of local\nresidents. However, it exceeds the soil management benchmark value of 10^-6 proposed by the US EPA,\nand prevention measures should be strengthened. The ecological risk and health risk assessment of\nheavy metals in soil quantitatively evaluates the risks of heavy metals in soil, which has a good guiding\nand exemplary role in risk prevention.

Rapid urbanization and industrialization have caused the continuous discharge of heavy metals into the soils of China’s Poyang Lake region, where they pose a major threat to human health. Yet, the spatial characteristics of these heavy metals in farmland soils and their pollution sources in this region remain unclear. This study was conducted to document the pollution caused by heavy metals in the Poyang Lake region through sampling that consisted of the collection of 215 soil samples from agricultural fields. The UNMIX model provided identification of the sources causing heavy metal pollution and source contributions to soil pollution. ArcGIS was used to study the spatial distribution of the eleven heavy metals and to validate the apportionment of pollution sources provided by the UNMIX model. Soil concentrations of heavy metals were above the local background concentrations. The average content of eight heavy metals, including Cd, Mo, Zn, Cu, Sb, W, Pb, and Ni, was approximately 1–6 times greater than natural background levels (6.91, 2.0, 1.67, 1.53, 1.23, 1.38, 1.11, and 1.24, respectively), while the average content of V, Cr, and Co was lower than natural background levels. The average contents of Cr, Ni, Cu, Zn, Cd, and Pb were all lower than the screening levels for unacceptable risks in agricultural land soils. The percentage of Cd content exceeded the risk screening value in all sampling sites, up to 55%, indicating that agricultural soils may significantly be affected by cadmium contamination. Five pollution sources of heavy metals were identified: natural sources, copper mine tailings, agricultural activities, atmospheric depositions, and industrial activities. The contribution rates of the pollution sources were 7%, 13%, 20%, 29%, and 31%, respectively. The spatial pattern of heavy metals was closely aligned with the outputs of the UNMIX model. The foregoing supports the utility of the UNMIX model for the identification of pollution sources of heavy metals, apportionment study, and its implementation in agricultural soils in the Poyang Lake region.