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The weathering and leaching of mining tailings have released large amounts of antimony (Sb) and arsenic (As), causing serious pollution in the surrounding soil, water, and sediments. To understand the leaching characteristics of Sb and As in mining tailings, Zuoxiguo and Qinglong mining tailings were collected for analysis. The average content of Sb in Zuoxiguo and Qinglong tailings was 5902.77 mg/kg and 1426.43 mg/kg, respectively, while that of As was 412.53 mg/kg and 405.26 mg/kg, respectively, which exceeded the local background value. Furthermore, the concentrations of Sb in the leachate of Zuoxiguo and Qinglong increased with time; the average Sb concentration in the leachate of Zuoxiguo and Qinglong was 1470.48 μg/L and 70.20 μg/L, respectively, while that of the As concentration was 31.20 μg/L and 6.45 μg/L, respectively. This suggests that the concentrations of Sb and As in the leachate of Zuoxiguo are both higher than those in the leachate of Qinglong and that the pH of the leachate of Zuoxiguo and Qinglong significantly changed within the first day under different initial pH conditions, and tended to be between 6 and 8, after one day. The results of the average health risk index showed that As in the leachate from Zuoxiguo and Qinglong for children was 5.67 × 10−4 and 9.13 × 10−5, respectively, and 4.43 × 10−4 and 7.16 × 10−5, respectively, for adults. As in the leachate from Zuoxiguo poses serious carcinogenic risks for residents, and in the study area, As poses a serious threat to human health. Therefore, the local government must manage As in these areas.

Based on the data of listed small and medium enterprises in China from 2007 to 2016, this paper uses Euler equation model and GMM method to analyze the financing constraints faced by SMEs and the role of commercial credit in easing financing constraints. The results show that financing constraints do exist in SMEs and cannot be eased by commercial credit. Therefore, small and medium enterprises need to find other ways to solve the financing problem. Research Hypothesis and Model Selection.As risk-averse financial institutions, banks tend to issue loans to companies with considerable amount of mortgage assets and well-groomed audited financial statements. Small and medium-sized enterprises are suffered with greater risks because of their unstable operation and opaque accounts;