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Soil pollution is becoming increasingly serious due to resource exploitation in mining areas, which directly affects the stability of the surrounding soil and water environment, and the accurate prediction of heavy metal pollution source analysis has an important guiding role in scientific mine remediation and treatment. On the basis of the previous study, in order to improve the interpretation of the soil media model, positive matrix factorization (PMF) and absolute factor analysis-multiple linear regression (APCS-MLR) models, which have a high degree of maturity and accuracy in the evaluation of heavy metal source analysis in soils, were further selected to enrich the UNMIX model in the previous study. The results of the multiple receptor models analyzing the sources of heavy metal contamination and the contribution of the sources were combined with the ecological risk assessment method to determine the most suitable model in study area under quantitative conditions. The results showed that: 1) the ecological high-risk areas were mainly concentrated in the south and east part of the study area, and Cd was the main risk element of the mine; the mean value of igeoaccumulation index was 3.75, which was highly consistant with the mean value of 731.22 for the potential ecological risk index though latter provided a more comprehensive evaluation of ecological hazards. 2) Comparing the results of the three models, the PMF model resolved four pollution sources: coal combustion source, natural-traffic integrated source, natural source and atmospheric deposition source, and the source contribution rates are 38.15%, 20.62%, 24.28% and 16.95%, respectively. 3) The fitted variables R2 in the PMF model reached to 0.96, which showed the best fitting effect. The PMF model refines source apportionment by accounting for sampling point errors and accurately ascertaining pollution sources and their contributions, making it highly suitable for complex mine-contaminated soils in realistic research settings. The findings of this study can provide a reference for tracing the origins of contaminants, which is essential for the remediation efforts of polluted soils following mining activities in the area. [ABSTRACT FROM AUTHOR]

The environmental restoration and ecological treatment of abandoned mining areas are of great significance for the construction of ecological civilization. In view of the heavy metal pollution in soil caused by mining, it is particularly important to carry out the investigation of heavy metal pollution characteristics and health risk assessment for the design and construction of mining treatment schemes. The pollution characteristics of soil heavy metals(As, Cd, Cu, Mn and Ni)of Dafanshan abandoned alum mining area in Lujiang county of Anhui province were analyzed, and the pollution assessment and human health risk assessment were established by combining the site accumulation index method, potential ecological risk index method and health risk assessment model(USEPA).The results show that the contents of As and Cd in the soil of the abandoned alum mining area significantly exceed the standard, and compared with the risk screening value of agricultural land, the exceeding rates are 77% and 100%, respectively; Cu in soil is slightly polluted, and the exceeding rate is 16%; the contents of Mn and Ni do not exceed the standard; in addition, the above five heavy metal elements in the descending order of the coefficients of variation are Ni, Mn, Cu, Cd and As; the study area has strong potential ecological risk, and the potential ecological risk index shows that As and Cd are the main risk elements, and the soil is mainly in quite-strong and very-strong potential ecological risks. The health risk assessment model shows that the indirect oral intake of excessive heavy metals in soil is the main route of non-carcinogenic and carcinogenic risks; As and Cd are within the acceptable ranges of non-carcinogenic and carcinogenic risks for adults and children through oral ingestion, and there is no carcinogenic risk for adults and children through respiratory ingestion and skin contact. [ABSTRACT FROM AUTHOR]

In the study, presence, distribution of 18 polychlorinated biphenyls (PCBs), including 7 indicator PCBs, 12 dioxin-like PCBs (DL-PCBs), and 4 heavy metals (Pb, As, Cd, Hg) have been investigated in Ictalurus punctatus, sediment and water from Jiangsu fish farms; thereafter, risk assessment have been conducted for the ecological risk and human health. The results showed that PCB28, PCB52, PCB114 were the most frequently found pollutants in all collected fish, sediment and water samples. Upon to the different geographical location of fishery farms across Jiangsu Province, components of PCBs presented differently, which implied different pollution sources. The concentration of PCBs found in sediment (178.4-457.2 pg/g) was higher than that detected in water (0.2-11.9 ng/L). Higher concentrations of PCBs was also found in fish meat (1.28-267.96 pg/g), compared to that in fish liver (0.64-95.46 pg/g), and guts and stomach (1.20-45.94 pg/g). Higher content of fat in fish meat could be the possibility of higher enrichment of PCBs compared to the other tissues. Meanwhile, higher concentration of heavy metal was found in sediment than that in water. The total enrichment of heavy metal in fish was found to be Pb﹥As﹥Cd﹥Hg in descend order. Total amount of heavy metals enriched in different tissues were found to be liver ﹥gastrointestinal system﹥meat. All the DL-PCBs TEQ (1.9 pg/g) is less than the maximum residue limit (MRL) of EU (6.5 pg/g). THQ (US, EPA) and R model were employed for the risk assessment by comprising the estimated daily intake and the daily allowed intake. The results revealed that the carcinogenic risk of 18 kinds PCBs and 4 kinds heavy metals remained acceptable level in this study. [ABSTRACT FROM AUTHOR]