页岩气开发对区域环境质量的潜在影响包括水力压裂过程对地下水的污染风险,返排水回到地表对地表水体的污染风险,甲烷泄露对区域大气环境质量的影响等。对页岩气开发区域的环境质量进行跟踪、监测和评价是确认污染防治措施效果和了解长期累积性环境影响的有效手段。对南川页岩气开发区域的污染防治措施进行了总结,重点监测了开发区域的地下水环境、地表水环境、大气环境、声环境和土壤环境。按照最不利原则,采用最大监测值的单因子指数对当前的环境质量状况进行了评价,对各要素环境质量的年际变化进行了评估。结果表明：各环境监测因子满足相应功能区的环境质量标准;各监测因子,尤其是氯化物等页岩气开发的特征污染因子的评价指数未发生明显年际变化,区域页岩气开发未造成各环境要素的污染和引起环境质量发生明显不利变化。虽然,当前采用的污染防治措施有效,但持续、累积性的环境影响尚需更长时间的跟踪监测与评价。

The potential impact of shale gas development on regional environmental quality include the risk of groundwater pollution during hydraulic fracturing, the risk of surface water pollution due to the backflow drainage, and the influences of methane leakage on regional atmospheric environmental quality. The way of tracking, monitoring and evaluating the environmental quality of shale gas production areas is effective to confirm the effects of pollution prevention measures and understand the long-term cumulative environmental impact. The pollution prevention measures in Nanchuan shale gas production area have been summarized. The groundwater environment, surface water environment, atmospheric environment, acoustic environment, and soil environment in the production area have been monitored. According to the most unfavorable principle, the single factor indexes with the largest monitoring value have been used to evaluate the current environmental quality, and the inter-annual changes of the environmental quality of each element has been assessd. The results show that the monitoring factors of surface water environmental quality, groundwater environmental quality, atmospheric environmental quality, acoustic environmental quality, and soil environmental quality in Nanchuan shale gas production area meet the environmental quality standards of the corresponding functional area. There is no significant inter-annual changes in the evaluation indexes of each monitoring factor, especially the characteristic pollution factor of shale gas development such as chloride. The regional shale gas development has not caused pollution of various environmental elements and significant adverse changes in environmental quality. Although the current pollution prevention measures are effective, the continuous and cumulative environmental impacts still require longer-term follow-up monitoring and evaluation.