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To identify the source and analyze the enrichment degree of soil cd in the limestone distribution areas of Guizhou Province, the geochemical baseline values of soil cd formed in different geological ages are obtained by standardized method, and the geoaccumulation index is used for evaluation. The results show that the baseline values of cd in the soil formed from the Permian and carboniferous limestone are obviously higher than those of the soil formed from limestone of other geological ages. The comparison between the baseline values of cd in soil and average content of cd in rocks shows that the naturally weathered rocks are the main source of soil cd in limestone areas. According to the evaluation results of geoaccumulation index, the pollution of soil cd in limestone areas of Guizhou is generally at a low level. [ABSTRACT FROM AUTHOR]

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Copyright of Nonferrous Metals (Mining Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Tea Science is the property of Journal of Tea Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

OBJECTIVES The open-pit mining of rare earth mines easily causes heavy metal pollution problems. Studies have shown that the soil of the rare earth mining area in southern Jiangxi has been polluted by heavy metals of Cd and Pb in low and moderate degrees. Environmental quality assessment usually uses pollution factors (total heavy metal content) as indicators of the degree of pollution, which can only reflect the degree of enrichment of heavy metals. OBJECTIVES To investigate the forms of heavy metals in the soil of the rare earth mining area in southern Jiangxi Province, migration ability and bioavailability. METHODS Based on the forms analysis of soil heavy metals measured by inductively coupled plasma-mass spectrometry (ICP-MS), the ecological risk of soil heavy metals in the rare earth mining area was evaluated using the geoaccumulation index method, potential ecological hazard index method and RAC risk assessment. RESULTS The heavy metals in the soil in the study area mainly existed in the residual form, accounting for 65.5% of the total. The average content of Cd and Pb in the soil samples was 1.72 times and 2.14 times the soil background value of Jiangxi Province, respectively. The average value of Cd in the soil in the farmland along the river downstream of the mine and the average value of Pb in the farmland near the tailing pond were 2.33 times and 3.06 times background value, respectively. The Cd or Pb content of the 22.7% samples exceeded the risk screening value. Among them, the exchangeable form of Cd and Pb accounted for 47.1% and 13.5% of the total amount, respectively, secondary to the residual form. Geoaccumulation index and potential ecological risk assessment results show that the accumulation degree and ecological risk level of Cd and Pb were higher, and Co, Ni, Cu, and Zn were lower. RAC risk assessment results show that Cd ecological risk was higher, whereas Co, Zn, and Pb was medium and Cu and Ni was low. Although the focal point and some results of the three evaluation methods were also different, the comprehensive conclusion showed that the soil Cd pollution and migration activities in the mining area were high, and the ecological risk was high. Conclusion The research results provide scientific basis for identifying the potential environmental risks of farmland soil in rare earth mining areas and propose effective prevention, emergency response and mitigation procedures.

Copyright of Environmental Science & Technology (10036504) is the property of Editorial Board of Environmental Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geology & Resources is the property of Geology & Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent decades, environmental problems caused by mining have become increasingly prominent, and environmental cases of heavy metal pollution were common. In this study, the water environment of Guohelada River in Leibo Shangtianba phosphate mining area, Sichuan Province was studied. The water and water sediment samples were collected. The concentration of arsenic, cadmium, cobalt, chromium, mercury, copper, zinc and lead in water sediments was measured. The degree of heavy metal pollution and potential ecological risk were evaluated by the method of accumulation index and potential ecological hazard index. Hydrochemical analysis indicated that the water body was HCO3--Mg2+-Ca2+ type water, and the controlling factor was rock weathering. The geoaccumulation index indicated that the primary pollution was As and Cd. The evaluation of potential ecological hazard index method shows that As, Cd ecological hazard is very strong, Hg ecological hazard is medium, and other heavy metals ecological hazard is slight. The correlation between As and Hg showed good correlation. Both the geoaccumulation index and the spatial distribution of potential ecological hazards show that the areas with high pollution degree and high ecological risk are located in the upper and middle reaches of the river. [ABSTRACT FROM AUTHOR]

Copyright of Rock & Mineral Analysis is the property of Editorial Board of Rock & Mineral Analysis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrometallurgy of China is the property of Hydrometallurgy of China Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Sedimentologica Sinica is the property of Acta Sedimentologica Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To assess the levels of arsenic and heavy metal pollution in abandoned agricultural soils, established pollution indices were used in this study. Nemerow’s pollution index, which is calculated based on the soil environmental quality standard, indicated that none of the soil sampling sites were polluted by As, Pb, Cr, Cd, and Hg. According to the geoaccumulation index, calculated based on soil geochemical backgrounds, the average geoaccumulation index values in the study area were ordered as follows: Hg (0.74) > Cd (0.17) > Cr (−0.18) > Pb (−0.33) > As (−0.92). In general, mercury and cadmium were accumulated in the topsoil, which may be influenced by human activities. [ABSTRACT FROM AUTHOR]

Copyright of Research of Environmental Sciences is the property of Research of Environmental Sciences Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Heavy metal pollution on urban roads is an important problem for the city environment. Lead pollution characteristics in the dusts around urban roads has been studied and assessed in Shihezi, west China. Pb concentrations and Pb isotopic compositions in dusts were measured using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The Geoaccumulation Index was applied to the assessment of the degree of Pb pollution. The results show that the range of lead concentrations in the dusts is 19.36-84.63 mg/kg (mean concentration: 37.85 mg/kg), which is higher than the local soil background value and lower than values in other big cities in China. The results indicate that a considerable Pb contamination in the Shihezi city environment was significantly affected by anthropogenic activities. The range of the Geoaccumulation Index is -0.59-1.54 (average value is 0.30), indicating that Pb is at the lightly to moderately polluted' level. The Pb isotope ratios in dusts (206Pb/207Pb: 1.159-1.182 and 208Pb/207Pb: 2.391-2.457) were similar to those in coal combustion and building materials.

China faces great challenges in protecting its soil from contamination caused by rapid industrialization and urbanization over the last three decades. In order to reduce the risk of heavy metals pollution, it is very essential to study soil heavy metal contamination characteristics and quantify the sources of soil heavy metals. The results of source apportionment can provide the scientific supporting for soil quality management in the specific region. In this study, a total of 173 soil samples at depth 0-20 cm were collected, and concentrations and spatial patterns of soil heavy metals (including cadmium, chromium, arsenic, mercury, lead, copper, zinc, nickel, manganese, cobalt, vanadium and selenium) in Lalin River basin were analyzed, which is one of the most typical agricultural areas in Northeast China. A Geographic Information System (GIS) was used to explore the variety of spatial distributions for 12 heavy metals. Geoaccumulation index and potential ecological risk index were applied to evaluate the degree of soil heavy metal contamination. Positive matrix factorization method was introduced to apportion the sources of soil heavy metals. Results demonstrated that the average concentrations of Cd, Cr, As, Hg, Pb, Cu, Zn, Ni, Mn, Co, V, and Se in soil samples were 0.13, 46.28, 10.12, 0.07, 23.38, 17.09, 54.06, 21.26, 575.4, 14.04, 62.11 and 0.158 mg/kg, respectively. The mean values of Cr, As, Pb, Cu, Zn, Ni, Mn and V did not exceed their respective soil background values, while the mean values for Co and Se were slightly higher than their background values in Lalin River. Concentrations of Cd and Ni in some soil samples were greater than the GradeⅡof the Standard according to the Soil Environmental Quality of China. The geostatistical interpolation results of heavy metal concentrations showed the spatial variations for these heavy metals were significant difference. According to the geoaccumulation index, the soils in Lalin River basin were mainly contaminated by Cd and Hg, with followed by As, with no or moderated contaminated level for the others. The geoaccumulation index values of 45.1% samples for Cd and 37.0% samples for Hg were greater than 0, while their mean values for the potential ecological risk index (RI) were 49.83 and 70.29, respectively. The range of RI was from 29.81 to 659.70, with a mean value of 140.18, indicating high ecological risk. Moreover, the potential ecological risk index on the left bank area was significantly higher than the right bank area of the Lalin River. A three-factor modeling resulting from PMF provided the most satisfactory results of soil heavy metals sources. Industrial activities, the application of pesticides and fertilizers were identified as the main anthropogenic sources for soil heavy metals in this study area, accounting for 29.4% and 32.6% of the total contribution, respectively. The remainder was the natural source, accounting for 38.0% of source contributions. The accumulation of Cd and Se in soils was mostly affected by agricultural activities, while Cr, Cu and Zn were also affected by some extent in this study area. For Hg and As, their content in soils was mainly associated with industrial activities. These suggested that the impact of human activities on soil heavy metals in Lalin River basin has exceeded the impact of natural source. Therefore, the use of pesticides and fertilizers and the “three wastes” emissions from key industrial enterprises in this area should be strictly controlled. [ABSTRACT FROM AUTHOR]

In order to clarify the spatial distribution characteristics and the present situation of heavy metal pollution in cultivated soil of a typical mining basin in southern China, the contents of Cd, As, Mn, Cu, Zn, and Pb in cultivated soil in the selected small watershed were determined, and the spatial distribution characteristics of heavy metals were analyzed using the spatial interpolation method. Further, the ecological risk was evaluated using the geo-accumulation index and potential ecological risk coefficient (PERC). The results showed that the average contents of Pb, Zn, Cu, As, and Cd in the topsoil (0-20 cm) in the small watershed were approximately 11.9, 3.8, 8.2, 4.7, and 14.2 times that of the background value in Hunan soil, respectively. Compared with the soil risk screening value of agricultural land, the over-standard rates of Pb, Zn, Cu, As, and Cd were approximately 24%, 56%, 75%, 44%, and 48%, respectively. Zn and Mn showed medium variation, whereas Pb, As, Cu, and Cd showed strong variation, which indicated that there was an obvious enrichment of heavy metals in the small watershed. The spatial analysis results showed that there was an obvious consistent characteristic of six heavy metals in the topsoil, that is, there was enrichment in the mining activity area and its downstream and the township streets in the west of the small watershed. Additionally, there were high value points of some heavy metals on both sides of the main river, indicating that the main pollution sources in the study area were mining and metallurgy activities and sewage irrigation. The results of the geo-accumulation index and potential ecological risk index showed that there was compound pollution of heavy metals, in which the degree of Cd pollution was the highest, and the soil of both sides of the river could pose the strongest potential ecological risk.

Pollution characteristics and risk of heavy metals in atmospheric deposition in core urban areas of Chongqing were investigated for one year from December 2017 to November 2018.Six functional zones:suburb, education area, residential area, commercial area, transportation hub, and industrial-residential area in Chongqing were selected for monthly atmospheric deposition collection. Concentrations of Cd, Cr, Ni, and Pb were analyzed using AAS. The potential ecological risk index and geoaccumulation index were used to evaluate the heavy metals pollution. Results show that the concentrations of Cd, Cr, Ni, and Pb in the atmospheric deposition were 1.59, 72.68, 20.99, and 101.17 mg·kg -1 , respectively, and their annual deposition fluxes were 0.39, 8.04, 2.41, and 10.41 mg·(m 2 ·a) -1 , respectively. Concentrations of heavy metals in autumn were significantly higher than those in the other three seasons, especially for Cd, and their deposition fluxes in winter were lowest. The potential ecological risk index of Cd was biggest, achieving a very high ecological hazard level, while the ecological risk of Cd and Pb in industrial-residential area was highest, and that of Cr and Ni, respectively, were highest in transportation hub and residential area. The geoaccumulation index indicated that the pollution of Cd was the highest, and that of Cr, Ni, and Pb was very low. The pollution in industrial-residential area and transportation hub was high, while that in the suburb was relatively low.

Arid and semi-arid regions in West China are ecologically fragile zones. Increasing attention has been focused on soil pollution triggered by mining and smelting in those areas. Nine heavy metals in the soil around a mining and smelting plant in Xinjiang were investigated using multivariate analysis, the geoaccumulation index, and GIS techniques. The heavy metals Cu and As were identified as the main pollutants in the study area. The accumulation of the heavy metals Cr, Zn, Ni, and Cd is small and weakly disturbed by human activity. Anthropogenic accumulation of Co and Pb was observed at a few sampling sites; its degree was also small. Anthropogenic accumulation of Mn in soil was not apparent. The factor analysis indicates two sources for the nine heavy metals in the soils. Source 1 includes As, Cu, Ni, Cr, Zn, Cd, and Co, while Source 2 includes Mn and Pb. The spatial distribution suggests that the sites with the highest As, Cu, Ni, Cr, Zn, Pb, Cd, and Co concentrations are in areas close to the tailing dump. The sealing tailing dump is the prior way to prevent the spread of heavy metals. The results also reveal that the PCA/APCS receptor model is not applicable for the quantification of the contribution of heavy metals in soils in this case.

PM 10 samples were collected from 45 sites around the electroplating factories in five towns in Dongguan at different times during all four seasons in 2015. The contents of 12 heavy metals (HMs) from the PM 10 samples were analyzed by ICP-MS. The seasonal and spatial distribution characteristics and the ecological risk were analyzed to provide a scientific foundation for the relevant department to make decisions regarding the environmental hazard, risk assessment and, pollution control. The results showed that PM 10 concentrations in the towns were lower than national standard level-Ⅱ, and the air pollution was heavier in winter than summer. The HM concentrations were higher in autumn and winter, and As, Cd, and Cr concentrations were higher than national standard (GB3095-2012). The concentrations of HMs in Humen, Shatian, and Dalingshan were much higher. The results for the enrichment factor and the geoaccumulation index indicated that Cd, Sb, Hg, and Co were in the extreme degree of pollution category, Pb and Zn were in the slight to extreme degree of pollution category, and Ni, Cr, Mn, and V were described as uncontaminated. The average potential ecological risk assessment (RI) of the HMs from the PM 10 samples was more than 600, which suggested an extremely serious ecological risk in the study area.

In order to analyze and compare the pollution characteristics and risks to human health of metallic elements in the PM 2.5 fraction of urban road dust (RD) and park road dust (PRD), particles smaller than 2.5 μm were suspended to filters by a re-suspension system and concentrations of Na, Mg, Al, Fe, Cu, Mn, Ni, Sb, Zn, Cd, and Pb were quantified. Results showed that the average concentrations of Cu and Sb in RD were 626 mg·kg -1 and 23 mg·kg -1 , significantly higher than that in PRD (274 mg·kg -1 and 11 mg·kg -1 ). This indicated that the elemental composition of RD was influenced by non-exhaust emissions. The geoaccumulation Index (I geo ) of each detected element showed that samples were strongly to extremely contaminated by Cd (4 < I geo < 5), moderately to strongly contaminated by Cu, Sb, Zn, and Pb (2 < I geo < 4), and uncontaminated to moderately contaminated by Ni and Mn (I geo < 1). The hazard index (HI) values of Sb, Pb, Cu, Ni, Zn, and Cd were less than 1 and the incremental lifetime cancer risk (ILCR) values of Ni and Cd were less than 10 -6 , indicating that these elements of RD and PRD are not associated with any cancer risks or non-cancer health risks.