To provide a comprehensive insight into the enrichment mechanism of gallium and indium in No. 9 coals, eighteen samples were collected from Anjialing mine, Ningwu Coalfield, Shanxi Province for coal petrological, mineralogical and geochemical analyses. The results suggested that Ga and In enrichment mainly hosted in the top horizons, with average concentration coefficients of 8.99 and 2.73 respectively, compared with the rest of horizons (2.46 for Ga and 1.69 for In). Source apportionment indicated that Ga and In were mainly derived from bauxite of Benxi Formation in Yinshan Oldland, while In could originate from felsic magmatic rocks in Yinshan Oldland as well. In addition, weak oxidation condition, medium to intensive weathering, transgression and input of terrestrial higher plants had positive effects on Ga and In enrichment. With the rapid expansion of emerging electronics manufacturing, Ga and In, of which potential risks on human health were neglected previously, were recently considered as hazardous elements. Therefore, this paper also discussed the potential pathways that these elements threatened human health. We suggested that potential risks on environment and human health caused by Ga and In enrichment in coals and coal-related products should be taken into account besides their economic value.
Polycyclic aromatic hydrocarbons (PAHs) are recognized as carcinogens that pose a severe threat to human health. Research on the temporal variation of PAHs was confined to monthly and seasonal investigations, and a longer timescale study remained inadequate until recently. Therefore, this study focuses on the decadal variation of PAHs in environmental media contaminated by a coal gangue dump in the Jiulong Coal Mine, Fengfeng, China. The results show that the total concentrations of PAHs have sharply declined compared to the past. The result of the paired-sample t-test indicates that several individual PAHs have obviously changed in concentration with statistical significance (p < 0.05). Moreover, proportions of medium-molecule weight PAHs increase with statistical significance (p < 0.01) when compared to the past. Various diagnostic ratios suggest that PAHs in previous samples are mainly derived from weathering products of coal gangue and vehicle exhaust, while PAHs in the present samples are dominated by those originating from pyrogenic sources. Calculation of incremental lifetime cancer risks (ILCRs) indicates high carcinogenic risk despite a considerable decrease in ILCR values by 2 to 3 orders of magnitude. It shows that recent measurements conducted by the local government do weaken the contamination of coal gangue dumps, but more attention to pyrogenic PAHs is necessary.
With continuous economic development and scientific and technical progress, global market competition is becoming increasingly stiff. Elementary knowledge of the supply chain management and e business of construction enterprise were introduced in this paper. Some problems of existing supply chain management of construction enterprise in e-business environment were analyzed. Measures and key factors for strengthening supply chain management of construction enterprise in e-business environment were discussed. It's proposed that cooperation and communication be reinforced and good relationship between suppliers and contractor be well maintained and third-party logistics and JIT delivery system be made better. Supply chain management and e business are effective tools for construction enterprise to save cost, shorten construction period and improve quality. E-business provides low-cost and convenient information support to supply chain management. Supply chain management of construction enterprise in e-business environment is important for improving competitiveness and economic and social benefits of construction enterprise
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