Per- and Polyfluoroalkyl Substances (PFAS) Update

Per- and polyfluoroalkyl substances (PFAS) have been among the most studied classes of chemical pollutants in recent years. With their properties of persistence, bioaccumulation, and long-range transport, perfluorooctane sulfonate (PFOS) and its related salts were added to the Stockholm Convention on Persistent Organic Pollutants at the 4th conference of the parties in 2009.¹ Recently, the related compounds perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS) have been proposed to be listed under the Convention. 

While many PFAS have been detected, scrutinized, and even withdrawn from production over the past two decades, recent interest has increased significantly with detection in ground and surface waters near application sites of aqueous film-forming foam (AFFF). AFFF is used extensively to suppress hydrocarbon fuel fires, and PFAS contaminants have been found in drinking water around burn sites, as well as training areas for municipal and military firefighters. Many of the compounds found in AFFF have been implicated as possible sources of groundwater contaminants such as PFOS and PFOA upon degradation.²

Per- and Polyfluoroalkyl Substances (PFAS)

AFFF products were initially produced via electrofluorination processes, though shortly thereafter the formulations were made via telomerization, a process yielding compounds with even-numbered perfluoroalkyl chains and various reactive groups separated by a non-fluorinated ethyl moiety. For many years, studies identified fluorotelomer sulfonates (FTS) as a major component of AFFF commercial formulations, with a common description of ×:2 for the perfluoroalkyl:ethyl chains. FTS compounds with perfluoroalkyl chain lengths of 4:2, 6:2, 8:2, and 10:2 are most commonly identified in the commercial products.³ With large volumes being introduced to the environment, and degradation pathways identified, these compounds represent a large concern for the environment and especially in water sources. CIL has recently developed native and ¹³C/D-labeled FTS standards, including the full set of 4:2, 6:2, 8:2, and 10:2 analytes. 

In late 2016, the US EPA announced a lifetime health advisory for exposure to PFOS and PFOA in drinking water. In response to regulatory action CIL has developed a set of PFOS/PFOA calibration and spiking solutions to assist with analysis of these two compounds at very low concentrations.

CIL also continues to develop new standards and standard mixtures to assist researchers with determination of PFAS in environmental, food, water, and human-exposure samples. In addition, CIL now offers a C₄-C₁₄ PFCA native standard mixture to go along with our C₄-C₁₀ PFAS native standard mixture.

Related Resources

➤ Standards for Environmental, Food, Water, and Exposure Analysis
➤ Analytical Standards for Human Exposure Analysis

References

1. Stockholm Convention www.pops.int
2. Place, B.J.; Field, J.A. 2012. Identification of Novel Fluorochemicals in Aqueous Film-Forming Foams Used by the US Military. Environ Sci Technol, 46(13), 7120-7127. Read more.
3. Schultz, M.M; Baretsky, D.F.; Field, J.A. 2004. Quantitative Determination of Fluorotelomer Sulfonates in Groundwater by LC MS/MS. Environ Sci Technol, 38(6), 1828-1835. PMID: 15074696