Potential ecological risk assessment of soil heavy metals contamination around coal gangue piles of Baodian coal mine area of Shandong, China

Surface soil samples from 12 sampling sites around coal gangue piles of Baodian coal mine area in Shandong Province, China were collected and analyzed. The results showed that the average concentrations of Cu, Cd, Pb and Zn in soil of Baodian coal mine area were up to 30.91, 1.97, 37.78 and 101.81 mg/kg, respectively, which are much higher than their natural background values of Shandong province. Soil of Liguanqiao village gangue piles displayed higher metal concentrations than that of Baojiachang village gangue piles. The values of contamination index (PI) in accordance with natural background values of Shandong province indicated that heavy metal contamination level was Cd>Zn>Pb>Cu, and Zn, Pb and Cu were moderate, Cd was high; Integrated contamination index (IPI) in accordance with natural background values of Shandong province revealed that heavy metal contamination level of different sampling sites was LGQGP-I-1>BJCGP-I-1>LGQGP-II-1>LGQGP-I-2>LGQGP-II-2>BJCGP-II-1>BJCGP-I-2> LGQGP-I-3> BJCGP-II-2> LGQGP-II-3> BJCGP-I-3> BJCGP-II-3; Potential ecological risk indexes (RI) of Hakanson further indicated that soil of Baodian coal mine area was suffering from considerable or heavy contamination of heavy metals. These results are important for the development of proper management strategies to decrease heavy metal contamination by various remediation practices in Baodian coal mine area, China.