Identification of Novel Fluorochemicals in Aqueous Film-Forming Foams Used by the US Military

TLDR

Aqueous film‑forming foams (AFFFs) are essential for fighting large hydrocarbon fires, but their fluorochemical surfactants—many of which are proprietary—have caused groundwater contamination from both controlled and uncontrolled releases. This study aims to fully characterize the fluorochemical composition of U.S. military AFFFs to better define the extent of groundwater contamination. The authors combined fast atom bombardment and high‑resolution quadrupole‑time‑of‑flight mass spectrometry with patent data to assign chemical formulas and structures for fluorochemicals in military‑certified AFFF samples.

Abstract

Aqueous film-forming foams (AFFFs) are a vital tool to fight large hydrocarbon fires and can be used by public, commercial, and military firefighting organizations. In order to possess these superior firefighting capabilities, AFFFs contain fluorochemical surfactants, of which many of the chemical identities are listed as proprietary. Large-scale controlled (e.g., training activities) and uncontrolled releases of AFFF have resulted in contamination of groundwater. Information on the composition of AFFF formulations is needed to fully define the extent of groundwater contamination, and the first step is to fully define the fluorochemical composition of AFFFs used by the US military. Fast atom bombardment mass spectrometry (FAB-MS) and high resolution quadrupole-time-of-flight mass spectrometry (QTOF-MS) were combined to elucidate chemical formulas for the fluorochemicals in AFFF mixtures, and, along with patent-based information, structures were assigned. Sample collection and analysis was focused on AFFFs that have been designated as certified for US military use. Ten different fluorochemical classes were identified in the seven military-certified AFFF formulations and include anionic, cationic, and zwitterionic surfactants with perfluoroalkyl chain lengths ranging from 4 to 12. The environmental implications are discussed, and research needs are identified.