关键词: 页岩气, 土壤重金属, 污染, 生态风险

Abstract: 【Objective】 To investigate the pollution of heavy metals in soil after shale gas exploitation. 【Method】 The heavy metals Cr,Ni,Cu,Zn,As,Cd,Pb in soils around 4 different function shale gas wells, including well-produced gas well field (S1), oil-bearing base treatment station (S2), drilling well field (S3) and gas gathering center station (S4) were determined. The single factor pollution index method, Nemerow comprehensive pollution index and potential ecological risk assessment were employed to analyze the effects of different shale gas wells exploitation on the concentrations of heavy metals in the soil. 【Result】 The average content of heavy metals in soil around each well field was lower than the control parameter ratio. The single factor index of soil heavy metal elements in each well field area were less than 1, and there was no pollution. The potential risk index of single heavy metal elements in each well field was less than 40, which was a mild risk. The Nemerow Comprehensive Pollution index in S1, S2, S3 and S4 was 0.88, 1.12, 0.89, 0.77, respectively, with a light heavy metal pollution level of S2 and a no pollution level of S1, S3, S4. The comprehensive potential ecological risk index in all well fields was less than 150, indicating a light risk level. 【Conclusion】 In conclusion, the exploitation of shale gas mining had no obvious influence on the concentrations of heavy metals in the soil around the well field, while the wells pose potential heavy metal pollution because of the high content of Cd in the soil before exploitation. Therefore, it is necessary to take some measures to reduce the mobility of heavy metals in soil for the food security production.

Key words: shale gas, soil heavy metals, pollution, ecological risk