Apportioning sources of environmental pollutants is key to controlling pollution. In this study, the sources of heavy metals to 234 agricultural soils from the Jianghan Plain (JHP) (∼22454 km2) in ...central China were discriminated between using Cd and Pb isotope compositions and multivariate statistical analyses. Concentrations of some metals in JHP soils (0.48 ± 0.2, 48.2 ± 15.9, 0.12 ± 0.23, 48.8 ± 16.4, 36.5 ± 9.8, and 96.8 ± 42.2 mg kg−1 for Cd, Cu, Hg, Ni, Pb, and Zn, respectively) were higher than background concentrations in Chinese soil. The Cd isotope compositions for the JHP soils (δ114/110Cd values −0.76‰ to −0.25‰) were similar to Cd isotope compositions found for smelter dust and incinerator fly ash, indicating Cd was supplied to the JHP soils by ore smelting and/or refining processes. The Pb isotope compositions for the JHP soils (206Pb/207Pb 1.182–1.195 and 208Pb/206Pb 2.078–2.124) were between the Pb isotope compositions found for Chinese coal and natural sources, which a binary isotope mixing model indicated contributed 52% and 48%, respectively, of the Pb in JHP soils. Cluster analysis and positive matrix factorization indicated that the sources of heavy metals in JHP soils may consist of smelting and/or refining activities, coal combustion, agricultural activities, and natural sources (including Han River sediment and soil parent materials). The isotope fingerprints and multivariate statistical analyses together indicated that coal combustion and smelting and/or refining activities were the main anthropogenic sources of heavy metals polluting JHP soils.
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•Multivariate statistics and isotope were used together to trace the pollution.•Limited contribution of agricultural activities to heavy metals in the soils.•Coal combustion and smelting/refining activities were main anthropogenic sources.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Corn is a crucial crop in China and is widely cultivated in the mercury (Hg) mining region of Guizhou. This study analyzed the Hg content in soil and corn plant samples from the Wuchuan Hg mining ...area (WCMA) and the surrounding non-Hg mining regions (SNMR). The findings suggest that ongoing ecological rehabilitation and environmental conservation measures in the WCMA have significantly decreased the Hg content in corn kernels. The Hg concentration in different parts of the corn plant varied, being higher in the roots, tassels, and leaves and lower in kernels and stalks. Hg stored in corn plant growing in the WCMA primarily originates from the soil (55.4%), while in the SNMR, it mainly comes from the atmosphere (74.9%). Despite counted only about 7% of the total plant mass, corn roots play a crucial role in soil Hg pollution remediation when corn is used for remediation. Household corn residues burning release about 58.5% and 66.9% of the stored Hg in corn plants growing in the WCMA and the SNMR, respectively, into the atmosphere. Our findings indicate that corn cultivation acts as a reservoir for both soil and atmospheric Hg in the SNMR, while in the WCMA, it serves as a source of atmospheric Hg.
•Ecological restoration in the WCMA significantly reduced mercury levels in corn kernels.•In WCMA, soil is the primary source of Hg in corn plants, while in the SNMR, the atmosphere dominates.•Proper handling the corn roots is crucial for using corn as a phytoremediation plant.•Corn cultivation serves as a Hg sink in the SNMR and a source of atmospheric Hg in the WCMA.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Soil pollution from metal(loid)s has become a severe environmental issue. Source identification of soil metal(loid)s is the basis for pollution prevention and control. In this study, a total of 31 ...surface soil samples were collected from farmland near a large lead/zinc (Pb/Zn) smelter in Zhuzhou City, central China. The sources of soil metal(loid)s pollution were identified with principal component analysis/absolute principal component scores (PCA/APCS), positive matrix factorization model (PMF), and Pb isotope fingerprints. Results showed significant accumulation of metal(loid)s in agricultural soils. The averages of soil Cd, Pb, and Zn concentrations were 7.90, 273, and 675 mg kg−1, respectively. Metal(loid)s pollution was mainly distributed in the vicinity of the Pb/Zn smelter and the soil metal(loid)s contamination near the surface was quite high. The sources of metal(loid)s included Pb/Zn smelting, waste incineration, and natural sources. Smelting was the major source of metal(loid)s pollution. The Pb binary isotope mixing model indicated that smelting contributed 74.4% of soil Pb. PCA/APCS showed that smelting contributed 70.3%, 80.6%, and 86.5% to soil Cd, Pb, and Zn, respectively, while PMF revealed that it accounted for 73.1%, 72.1%, and 70.6%, respectively. Our study demonstrated that the combination of receptor models and isotope methods was comprehensive and effective for source identification, which provided new insights into determining the sources of soil metal(loid)s pollution.
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•Obvious enrichment of soil Cd, Pb, and Zn was found in study area.•Pb isotope fingerprints, PCA/APCS, and PMF were used to trace soil metal(loid)s.•The sources of soil metal(loid)s included Pb/Zn smelting, waste incineration, and natural sources.•Pb/Zn smelting contributed over 70% of soil metal(loid)s contamination.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A series of representative street dust samples were collected from a heavily industrialized city, Zhuzhou, in central China, with the aim to investigate the spatial distribution and pollution status ...of 17 trace metal/metalloid elements. Concentrations of twelve elements (Pb, Zn, Cu, Cd, Hg, As, Sb, In, Bi, Tl, Ag and Ga) were distinctly amplified by atmospheric deposition resulting from a large scale Pb/Zn smelter located in the northwest fringe of the city, and followed a declining trend towards the city center. Three metals (W, Mo and Co) were enriched in samples very close to a hard alloy manufacturing plant, while Ni and Cr appeared to derive predominantly from natural sources. Other industries and traffic had neglectable effects on the accumulation of observed elements. Cd, In, Zn, Ag and Pb were the five metal/metalloids with highest pollution levels and the northwestern part of city is especially affected by heavy metal pollution.
•Large-scale Pb/Zn smelters contributed to elevated trace elements in the street dust.•The hard alloy processing caused the enrichment of a few elements.•Cd, In, Zn, Ag and Pb were the most polluted elements.•Northwestern Zhuzhou suffered severe contamination for a range of trace elements.
Pb/Zn smelting and hard alloy processing operations have caused seriously contamination of trace metal/metalloids in the street dust.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In the present study, magnetic measurements were combined with geochemical analysis and stable Pb isotopic ratios to reveal the distribution and origination of trace metal pollutants in kindergarten ...dusts from a typical urban environment of Wuhan, central China. The geoaccumulation index (Igeo) of magnetic properties was more prominent than those of individual metals. The magnetic susceptibility (MS) and trace metals (Zn, Pb, and Cu) in this study together with published results from other Chinese cities formed a liner relationship, suggesting that metal contaminants in Chinese urban areas had similar MS to metal ratios, which could be used as an indicator for identification of pollution sources between Chinese cities and the other Asian cities. Stable Pb isotopic ratios (1.1125–1.1734 for 206Pb/207Pb and 2.4457–2.4679 for 208Pb/207Pb) in the urban dusts from Wuhan were characterized by higher 208Pb component in comparison with those from other Chinese cities. This result combined with principal component analysis (PCA) indicated that metal pollutants in the dusts were derived from industrial activities and coal combustion, whereas the traffic emissions were no longer a predominant pollution source in urban environment. Our study demonstrated that environmental magnetic methods could not only reveal the overall situation of trace metal contamination, but also prove evidence in the identification of pollution sources.
•Magnetic measurements were combined with geochemical and Pb isotopic analyses.•Magnetic properties showed more prominent values of Igeo than those of individual metals.•Metal pollution sources were identified by Pb isotopes and PCA.•Industrial emissions and coal combustion are major metal pollution sources in urban areas.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
► Elevated magnetic particles and heavy metals coexist in dust. ► Morphology and mineralogy of magnetic particles were studied by SEM-EDX and XRD. ► Magnetic minerals in the dust consist of ...magnetite, hematite, and metallic iron. ► Impact of metallic iron particles and multi-sources of metal pollutants was notable.
Magnetic method is a reliable and powerful technique for identification of the relative contribution of industrial pollutants. However, it has not been fully applied in urban area impacted by non-ferrous metal (NFM) smelting/processing activities. The aim of this study is to explore the applicability of magnetic methods for detecting heavy metal contamination in dust from three NFM smelting/processing industrial cities (Ezhou, Zhuzhou, and Hezhang) in China. The enhancements of magnetic susceptibility (MS) and saturation isothermal remanent magnetization (SIRM) together with heavy metals were significant in the studied areas in comparison with the background values. Scanning electron microscope (SEM) analysis revealed that magnetic particles in dust from Ezhou were dominated by spherules, while those from Zhuzhou and Hezhang were mainly consisted of irregular-shaped particles. κ–T curves and X-ray diffraction (XRD) analyses indicated that the magnetic particles from Ezhou were dominated by magnetite and metallic iron, whereas those from Zhuzhou and Hezhang were consisted of magnetite and hematite. Our study indicates that magnetic properties of the dust are sensitive to the NFM smelting/processing related heavy metal pollutants. However, the relationship between magnetic parameters and heavy metals was influenced by the presence of metallic iron particles and multi-sources of metal pollutants.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The Pearl River Delta (PRD) is one of the most industrialized and urbanized regions in China. In order to assess the pollution status of mercury (Hg) in PRD river system, the distribution of total ...mercury (HgT) and methylmercury (Me-Hg) in sediment from a large river named Dongjiang (DJ) was for the first time investigated. HgT concentrations in sediment increased from the upstream to downstream of Dongjiang area and at most sites of DJ were significantly higher than the background values, which suggested that the DJ was contaminated with Hg, especially in the downstream of DJ. Me-Hg concentrations in sediment of DJ ranged from 0.56 to10.62
ng/g, and were significantly correlated with HgT and organic matter. In order to determine the potential Hg contamination sources, typical sediments from different parts of DJ were chosen for Hg isotope analysis. The results showed that the mass-dependent fraction (MDF) in the sediments varied significantly (δ
202Hg: −2.35 to−
0.60‰), and the mass-independent fraction (MIF) in the sediments also varied considerably (Δ
199Hg: −0.02 to −
0.27‰). The samples with the highest HgT located in the industrial area had the highest δ
202Hg (−
1.14‰ to −
0.60‰) measured values and insignificant MIF (Δ
199Hg: −0.04 to −
0.01‰). Meanwhile, the samples with the lowest HgT located in the background area had the lowest δ
202Hg (−
2.16‰ to −
1.55‰) and Δ
199Hg (−
0.20 to −
0.27‰) measured values. Unlike the above two cases are the samples located in the urban area, which have relative lower MDF (δ
202Hg: −2.35‰ to −
1.96‰) and small but significant MIF (Δ
199Hg: −0.10‰ to −
0.08‰) with relative higher HgT. We demonstrated that the dominant Hg sources in DJ sediments could be categorized as the regional background, urban and industrial sources. In our study, we demonstrated that Hg stable isotope method could serve as an effective tool for tracing mercury contamination sources in the environment.
► Hg distribution and Hg isotope ratios in sediment of Dongjiang was investigated. ► The river sediment was contaminated with Hg due to human activities. ► A triple source mass balance using both MDF and MIF signatures was establised. ► Different sources of mercury contaminations have distinct mercury isotope signatures. ► The contributions of mercury from different sources were calculated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The chlor-alkali industry, which is one of the largest mercury (Hg) consumption and emission sectors in China, may lead to serious Hg pollution of the environment. In this study, we investigated Hg ...contamination in groundwater, stream water and sediment, the atmosphere, and soil around an abandoned chlor-alkali plant (CAP) in southwest China. The results indicated that the dissolved mercury (DHg) concentrations in groundwater within the CAP exceeded the national limit in 46.4% of the samples, and that this was a result of Hg leaching from upper contaminated salt slurry and soil. Moreover, THg concentrations of surface water and sediment were highly elevated, with maximum levels of 1940 ng/L and 74.6 mg/kg, respectively. Total gaseous mercury (TGM) levels inside the plant were also significantly elevated compared with those outside, which indicated the impact of Hg release from the salty slurry. The THg enrichment factors in surrounding soils ranged from 1.56 to 22.5 (with a mean of 7.18) compared with the regional background, while 28.6% exceeded the second-grade national limit of China. The spatial distribution of THg concentrations in the surrounding soils revealed a unique pattern, with a peak 1–1.25 km from the CAP. Overall, the results indicate that Hg release from the CAP has caused serious pollution of the surrounding environment.
•Impacts of mercury (Hg) pollution from an abandoned chlor-alkali plant (CAP) were evaluated.•Serious Hg contamination in groundwater, stream water, stream sediment, the atmosphere, and soils.•Spatial distribution of total Hg concentrations in the surrounding soils and atmospheric Hg confirmed Hg pollution from the CAP.•Appropriate remediation practices are needed to restore Hg pollution in the CAP.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
