Groundwater remediation: the next 30 years

Area of Science:

• Environmental Science
• Hydrogeology
• Environmental Engineering

Background:

• Groundwater remediation strategies rely on prevailing conceptual models of contaminant hydrogeology.
• These models evolve with new research, technologies, and performance data.
• Recent studies indicate significant challenges in meeting Maximum Contaminant Levels (MCLs) at contaminated groundwater sites.

Purpose of the Study:

• To critically evaluate the traditional "reach MCLs" approach in groundwater remediation.
• To introduce and advocate for a revised remediation strategy incorporating new concepts.
• To address the limitations of current remediation practices in achieving regulatory standards.

Main Methods:

• Review of multiple-site remediation performance studies.
• Analysis of recent groundwater research, particularly on matrix diffusion.
• Discussion of emerging concepts like mass discharge and orders of magnitude (OoMs).

Main Results:

• Matrix diffusion is identified as a primary constraint in achieving MCLs.
• The conventional "reach MCLs" approach has proven difficult to implement successfully.
• New metrics such as mass discharge and OoMs offer potential improvements.

Conclusions:

• The traditional approach to groundwater remediation focused on reaching MCLs is often insufficient.
• A paradigm shift towards a new approach utilizing orders of magnitude (OoMs) and mass discharge is recommended.
• This revised strategy aims for more realistic and achievable groundwater remediation goals.