The Importance of Understanding Mass Distribution and Flux in Developing Remedial Strategies for PFAS Contamination

PFAS has attracted significant attention as an emerging contaminant of environmental concern in Australia, and many sites are in the process of detailed investigation and in the development of remedial and management strategies. The issue is difficult, because the criteria being applied for soil, groundwater and surface water can be very low, and it is not feasible to treat PFAS contamination that has become widely distributed in soil and groundwater.

PFAS contamination in source areas can leach out slowly, resulting in PFAS in groundwater that travels far distances. While the resulting mass of PFAS in groundwater can be much less (perhaps 1000 fold) that in the soil source area, the resulting groundwater concentrations can far exceed (one hundred to one million fold) the guideline levels for protection of human health and aquatic ecosystems.

The preferred remedial strategy in such cases may involve a combination of management and remediation methods to destroy or contain most of the contaminant mass in the source area, to intercept contamination that is leaching off site, and to manage the contamination that is off site.

With the information now at hand it is possible to estimate the aggregated cost to achieve various outcomes that would correspond to particular regulatory policy settings and guideline levels, with the resulting cost potentially ranging from hundreds of millions to billions of dollars. A typical case example is used to illustrate the issues.

Because of this, it is important to adopt a risk-based sustainable management and remediation framework for decision making that provides the best balance to outcomes and stakeholder concerns.