PFOA and PFOS are the two most commonly encountered examples of Per- and Polyfluoroalkyl Substances (PFAS). PFOA and PFOS are abbreviations for the chemicals “perfluorooctanoic acid” (PFOA) and “perfluorooctanesulfonic acid” (PFOS). While government regulations have been passed to eliminate the use of these contaminants in manufacturing and other business practices due to the health risks they pose, these compounds are recalcitrant, i.e. not readily degradable, and as a result are ubiquitous in the environment.
Historically, PFAS compounds were used in various industrial activities and were components in many industrial and consumer products because they exhibit many useful properties. As the United States EPA has indicated in their research findings, they are resistant to heat, water, and oil, and also resist degradation in the environment. You may be familiar with technologies such as Teflon, Goretex, and firefighting foams, which have PFAS compounds incorporated. From clothing to cooking – many have used products containing PFAS in their day-to-day activities. These chemicals are of concern because they have now been detected in groundwater, drinking water, and soils in many of our local communities. This creates a potential exposure pathway to humans and possible health risks.
Potential health effects of PFAS
Studies have indicated that PFAS poses potential threats to human health. According to the US Agency for Toxic Substances and Disease Registry (ATSDR), a division of the American Center for Disease Control (CDC), PFAS can have negative effects on fetal and child development, adult hormones and fertility, high cholesterol, in addition to posing other health risks. As a result, the US EPA has now started requiring the monitoring of drinking water and set lifetime drinking water advisory levels at 70 parts per trillion (ppt) for PFOA and PFOS. The EPA has also indicated that they will set screening levels and site-specific cleanup levels at Superfund sites, which will be used to determine if long-term groundwater remediation or soil remediation is needed.
Groundwater remediation of PFAS compounds
To date, the use of traditional means of groundwater remediation of PFAS plumes has proven difficult. Because they are extremely robust compounds, remediation technologies such as in situ chemical oxidation (ISCO) and various forms of bioremediation have been unable to address these contaminants. The most prevalent method at this time is to use an ex situ pump and treat system with activated carbon filters. However, this process can prove very expensive and challenging due to the extremely wide-area, dilute formation of the most common PFAS plumes.
REGENESIS has developed an in situ remediation product called PlumeStop® Liquid Activated Carbon™ that has the potential to solve the challenges faced in the groundwater remediation of PFAS. This technology can be applied under low-pressure injection, which solves the problem of excessive costs incurred with pump and treat systems. Through the use of a proprietary organic polymer dispersion chemistry, the activated carbon achieves high distribution through the subsurface and removes contaminants like PFAS rapidly from groundwater.
The video above presents a case study of the first ever in situ treatment of PFAS on a commercial site. IN SITU Remediation Ltd used PlumeStop® on the impacted site, rapidly removing the PFAS contamination from the groundwater through sorption. The PFAS concentrations have since remained at non-detect for over 15 months, with conservative modelling by Grant Carey estimating that the longevity of the PlumeStop treatment will be 100 years or more.
PFAS groundwater remediation strategies
With PlumeStop, remediation professionals gain a solution that will provide an effective, more economical means of stopping the migration of PFAS plumes long-term, thereby protecting sensitive receptors. There are many possible strategies for the in situ containment of PFAS using PlumeStop. Click here for example approaches: Remediation strategy examples
Regardless of the groundwater remediation strategy that is devised — and there are more than the above listed approaches – PFAS remediation will need to be addressed in the years to come. It is a persistent contaminant and environmental professionals across the globe are going to be facing challenges due to its indestructibility and high cost to remediate, coupled with the remediation driver of potential threats to human health. PlumeStop can be leveraged as an answer to some of these problems.
Questions about your site?
If you would like to discuss whether PlumeStop might be an effective remediation solution for your contaminated site, please contact us. Our team of remediation experts are here to answer questions, provide advice, and if you have site characterisation data, develop a remediation design for your site free of charge.
- PlumeStop product page
- PlumeStop technical bulletin 5.1
- US Interstate Technology Regulatory Council (ITRC) – PFAS Factsheets with an overview of PFAS water and soil values including Western European countries
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