地下水修复的技术不可达性及美国管理对策对我国的启示

Technical Impracticability of Groundwater Remediation and Management Countermeasures in the USA and Lessons Learned for China

  • 摘要: 由于地下水文地质条件的非均质性、污染物环境行为的多样性、修复技术应用的局限性等原因,地下水修复过程存在较大的不确定性,导致出现修复时间和资源的消耗与修复预期不匹配等问题,对地下水修复效果评估和场地再开发利用带来压力. 美国提出了地下水修复技术不可达性的概念,推行了技术不可达豁免政策,将技术不可达评估纳入地下水修复管理程序中,并提出适应性管理、低风险结案、长期监测等一系列管理要求,以保障场地修复后的健康风险和环境风险. 我国尚未建立技术不可达情景的应对措施和技术体系,在复杂污染场地地下水修复中仍存在修复目标、修复周期、修复效果评估周期等各方面的挑战. 本文围绕地下水修复的技术不可达性,借鉴美国污染场地管理经验,提出了修复技术不可达情景下的应对策略,包括建立修复过程跟踪管理技术体系、适时开展残留污染物风险评估、严格落实污染场地后期管理等建议,以期为保障修复后场地再开发安全利用提供理论依据和技术支撑.

     

    Abstract: Contaminated groundwater in many places is usually very difficult to remediate and has become a serious environmental problem in China. The heterogeneity of hydrogeological conditions, complexity of contaminant behavior, and limitations of remediation technologies require long-term remediation time frames and significant resource consumption, thus hindering the redevelopment and utilization of those contaminated sites. To cope with this issue, the US EPA proposed the concept of technical impracticability, which is determined based on site-specific characterization and remediation performance data. Furthermore, the ITRC proposed an adaptive management framework for dynamically refining the conceptual site model, setting up site objectives, and developing interim objectives and adaptive remedial strategies. Similarly, low-risk site closure is implemented on the site that is not completely cleaned up but actually poses minimum risk to human health and the environment. All of them need long-term management. China has not yet established countermeasures for technology impracticability, and there are still challenges in the remediation of complex contaminated ground water. Based on the lessons learned from the USA, we recommend the following strategies for groundwater remediation in China: establish a technical system for tracking the remediation process; carry out risk assessment of residual pollutants, and implement the long-term management of contaminated sites. The proposed management framework and tools will provide scientific support for the redevelopment of contaminated land in China.

     

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