The Analysis of Per and Polyfluorinated Alkyl Substances (PFAS) - Challenges and Best Practices

Characterization of Polyfluoroalkyl Substances in the Environment
Oral Presentation

Prepared by

Contact Information:; 916-374-4378


PFAS are a family of synthetic compounds containing thousands of chemicals formed from carbon (C) chains with fluorine (F) attached to these chains. The C-F bond is the shortest and strongest bond in nature, and is responsible for most of the unique and useful characteristics of these compounds. Perfluorooctane sulfonate (PFOS) and Perfluorooctanoic acid (PFOA) are fully fluorinated organic compounds and are the most common PFAS produced in the United States. PFOS and PFOA are used in a wide variety of industrial and commercial products such as textiles, leathers, aqueous film forming foams (AFFF), metal plating, photo lithography, semi-conductors, paper and food packaging, coating additives, cleaning products and pesticides.
PFOS and PFOA are persistent in the environment and resistant to typical environmental degradation processes. As a result, they are widely distributed and are found in soil, sediments, groundwater, air and tissue across the United States. According to U.S. EPA, PFOA and PFOS pose potential adverse impacts to the environment and human health due to the bio accumulative and mobile nature of the compounds.
In 2006, the United States Environmental Protection Agency (USEPA) announced the PFOA Stewardship Program, to phase out the emissions and the use of long-chain perfluorinated chemicals (PFCs), by December 31st, 2015. In addition, the USEPA and state agencies have developed health based advisories or screening levels. The current USEPA lifetime health advisory for PFOA and PFOS is 70 ppt each or in total if both compounds are present. State levels vary widely and care must be taken to determine which apply to each program.
The chemistry and analysis of PFAS is unique and challenging. There is currently no consensus best method for all environmental matrices. The USEPA published Method 537, Version 1.1 in 2009. This method is applied to drinking water matrices only. Several other methods have been published for PFAS including ISO Method 25101, ASTM D7979 and D7968. In order to meet client needs, environmental laboratories have adopted Method 537 and developed significant modifications. In general, the modifications applied are similar between labs, but the opportunity exists for labs to make unique and unqualified modifications. The inconsistent adoption of these modifications yields opportunity for data variability over time and between labs. Hence, stakeholders must work hard to select an analytical method capable of meeting their project and regulator objectives.