Analysis of organophosphate hydraulic fluids in US Air Force base soils

Tri-aryl and tri-alkyl organophosphates (TAPs) have been used extensively a s flame-retardant hydraulic fluids and fluid additives in commercial and mi litary aircraft. Up to 80% of the consumption of these fluids has been esti mated to be lost to unrecovered leakage. Tri-aryl phosphate components of t hese fluids are resistant to volatilization and solubilization in water, th us, their primary environmental fate pathway is sorption to soils. Environm ental audits of military air bases generally do not include quantification of these compounds in soils. We have determined the presence and extent of TAP contamination in soil samples from several U.S. Air Force bases. Soils were collected, extracted, and analyzed using GC/FPD and GC/MS. Tricresyl p hosphate was the most frequently found TAP in soil, ranging from 0.02 to 13 0 ppm. Other TAPs in soils included triphenyl phosphate and isopropylated t riphenyl phosphate. Observations are made regarding the distribution, typic al concentrations, persistence, and need for further testing of TAPs in soi ls at military installations. Additionally, GC and mass spectral data for t hese TAPs are presented, along with methods for their extraction, sample cl ean-up, and quantification.