To investigate the geochemical characteristic, genetic types, and accumulation model of coalbed methane (CBM), 16 samples from a burial depth of 621–1494 m were collected in the Panxie Coal Mining Area of Huainan Coalfield. The results indicate that the samples are dominated by methane, and the concentrations are distributed in the range of 73.11–95.42%. The dryness coefficient is 0.77–1.00 (average, 0.93), and the ratio of methane to the sum of ethane and propane (C 1 /(C 2 + C 3 )) is 3.18–242.64 (average, 36.15). The δ 13 C CH 4 values are distributed in the range of −65.44 to −32.38‰ (average, −45.22‰), the δD CH 4 values are in the range of −226.84 to −156.82‰ (average, −182.93‰), and the δ 13 C CO 2 values are in the range of −19.7 to −10.1‰ (average, −15.51‰). CBM samples in the study area are dominated by thermogenic gases, followed by secondary biogenic gases with CO 2 reduction. For the percentages of different genetic gases, the distribution range of thermogenic gas is 70.11–97.86%, whereas that of biogenic gas is 58.65–77.86% for five samples from Zhangji, Panyi, Pansan, and Panbei Coalmines. Moreover, desorption-diffusion fractionation and the effect of groundwater dissolution occurred in the Panxie Coal Mining Area, and higher δ 13 C CH 4 values mostly existed in the deeper coal seams. Furthermore, the biogenic gases are more likely to be secondary biogenic gases generated by CO 2 reduction on the basis of data comparison, which is related to the flowing water underground. Accumulation models of different genetic types of CBM are correlated with the burial depth of coal seams, location, and type of faults and aquifers.

To understand the content, pollution, distribution and source and to establish a geochemical baseline of heavy metal elements in soil under the influence of high-density population, the concentrations of heavy metal elements Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Hg, Pb and Fe were determined in 23 soil samples in Suzhou University, and geo-accumulation index, enrichment factor, principal component analysis, spatial analysis and regression analysis were completed. The results showed the following: The elements Cu and As were slightly polluted, while the other heavy metal elements were not. The elements Cd, Cu, Ni and As in soils were mainly caused by agricultural activities of chemical fertilizer, whereas the elements Zn and Hg were impacted by the chemicals and batteries. The heavy metal elements in the north were lower than in the south of the campus, as a whole. The enrichment of elements Cu, As and Cd was caused by the east–west river on the campus, and the enrichment of the elements Mn, Ni and Zn was induced by the reservoir. Biochemical experiments and vehicle parking influenced the spatial enrichment of Cr, Co and Pb, while domestic waste led to the spatial differentiation of Hg concentrations. The regression curve between heavy metal elements and Fe was established, and the background values of the heavy metals Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Hg and Pb are 50.90, 489.37, 11.76, 37.74, 55.70, 58.22, 20.07, 0.09, 0.08 and 24.13 mg/kg, respectively.