Social ecological system framework as a decision-making tool for risk mitigation: A superfund site case study

Area of Science:

• Environmental Science
• Risk Assessment
• Environmental Engineering

Background:

• Vapor intrusion (VI) via subsurface piping, known as conduit VI, complicates risk assessment at hazardous waste sites.
• Superfund sites present unique challenges due to numerous stakeholders with diverse interests impacting risk management.
• Existing risk management practices for conduit VI are evolving and require adaptable decision-making tools.

Purpose of the Study:

• To propose a social ecological system (SES) framework as a decision-making tool for conduit VI risk mitigation.
• To demonstrate the applicability of the SES framework using field data from a California Superfund site.
• To inform risk mitigation implementation and long-term efficacy by considering stakeholder roles and interests.

Main Methods:

• Application of the SES framework to a Superfund site near San Francisco, California.
• Evaluation of sewer invert elevation, groundwater elevation, and pre/post-mitigation volatile organic compound (VOC) concentrations.
• Analysis of stakeholder interactions and their influence on mitigation activities.

Main Results:

• Identified a sewer line above the groundwater table as an unexpected source of conduit VI risk.
• The SES framework effectively integrated stakeholder perspectives into the decision-making process.
• Gas siphons were selected and implemented as the successful mitigation technology for the studied site.

Conclusions:

• The SES framework provides a valuable approach for managing conduit VI risks at complex hazardous waste sites.
• Stakeholder engagement is crucial for effective risk mitigation and ensuring the long-term success of implemented solutions.
• Findings offer key considerations for advancing risk management strategies, particularly for vapor intrusion concerns at Superfund sites.