W5 AM Perfluorochemical Monitoring
Wednesday, 16 November 2005: 8:00 AM - 11:40 AM in 321-323

(HIG-1117-750918) Quantitative Determination of Perfluorochemicals in Sediments and Domestic Sludge.

Higgins, C¹, Handler, N², Boehm, A¹, Paytan, A², Field, J³, Criddle, C¹, Luthy, R¹, ¹ Department of Civil & Environmental Engineering, Stanford University, Stanford, CA, USA² Department of Geological & Environmental Sciences, Stanford University, Stanford, CA, USA³ Department of Environmental & Molecular Toxicology, Oregon State University, Corvallis, OR, USA

ABSTRACT- Perfluorochemicals (PFCs) are the subject of increasingly intense environmental research. Despite their detection both in biota and in aqueous systems, little attention has been paid to the possible presence of this class of compounds in solid environmental matrices. The limited available data indicate that some PFCs such as perfluorooctane sulfonate (PFOS) may strongly sorb to solids, and sewage sludge is widely suspected as a major sink of PFCs entering municipal waste streams. A quantitative analytical method was developed that consists of liquid solvent extraction of the analytes from sediments and sludge, clean-up via solid phase extraction, and injection of the extracts into a liquid chromatography system coupled to a tandem mass spectrometer (LC/MS/MS). The limits of detections of the method were analyte and matrix dependent, but ranged from 0.7 to 2.2 ng/g and 0.041 to 0.246 ng/g (dry weight) for sludge and sediment, respectively. A demonstration of the method was performed by conducting a limited survey of domestic sludge and sediments. Aqueous concentrations of nutrients were also measured at these sediment sampling sites. The concentration of PFCs in domestic sludge ranged from 5 to 152 ng/g for total perfluorocarboxylates and 55 to 3370 ng/g for total perfluoroalkyl sulfonyl-based chemicals. Data from a survey of San Francisco Bay Area sediments suggest widespread occurrence of PFCs in sediments at the low ng/g to sub-ng/g level. In addition, strong correlations were evident between PFOS levels (sum of PFOS and all quantified PFOS precursors) and other indicators of sewage pollution such as ¹⁵N, ortho-phosphate and ammonium (R² values of 0.67, 0.90, and 0.87, respectively), suggesting sewage may be a source of PFCs such as PFOS in urban sediments. Finally, substances that may be transformed to PFOS, such as 2-(N-ethylperfluorooctanesulfonamido) acetic acid (N-EtFOSAA), are present in both sediments and sludge at levels often exceeding PFOS.

Key words: PFCs, PFOS, sediment, sludge