Sorption behaviour of per- and polyfluoroalkyl substances (PFASs) as affected by the properties of coastal estuarine sediments

Danielle P Oliver; Divina A Navarro; Jeff Baldock; Stuart L Simpson; Rai S Kookana

doi:10.1016/j.scitotenv.2020.137263

Sorption behaviour of per- and polyfluoroalkyl substances (PFASs) as affected by the properties of coastal estuarine sediments

Sci Total Environ. 2020 Jun 10:720:137263. doi: 10.1016/j.scitotenv.2020.137263. Epub 2020 Feb 20.

Authors

Danielle P Oliver¹, Divina A Navarro², Jeff Baldock³, Stuart L Simpson⁴, Rai S Kookana⁵

Affiliations

¹ CSIRO Land and Water, Locked Bag 2, Glen Osmond, South Australia 5064, Australia. Electronic address: Danni.Oliver@csiro.au.
² CSIRO Land and Water, Locked Bag 2, Glen Osmond, South Australia 5064, Australia; Soil Science, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia 5064, Australia. Electronic address: divina.navarro@csiro.au.
³ CSIRO Agriculture, Locked Bag 2, Glen Osmond, South Australia 5064, Australia. Electronic address: jeff.baldock@csiro.au.
⁴ CSIRO Land and Water, Locked Bag 2007, Kirrawee, New South Wales 2232, Australia. Electronic address: stuart.simpson@csiro.au.
⁵ CSIRO Land and Water, Locked Bag 2, Glen Osmond, South Australia 5064, Australia; Soil Science, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia 5064, Australia. Electronic address: rai.kookana@csiro.au.

PMID: 32145609
DOI: 10.1016/j.scitotenv.2020.137263

Abstract

The sorption of three perfluoroalkyl substances (PFASs), namely perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonic acid (PFHxS), was determined in 19 coastal sediments. There are currently limited data on the sorption behaviour of these chemicals in marine or estuarine sediments and the properties controlling their sorption have not been well established. The median average PFOS K_d value (30.4 L/kg) was >8 times that for PFOA (3.3 L/kg) and PFHxS (2.8 L/kg). Highly significant (P < .001) linear relationships were found between values for sorption coefficients (K_d) for all three chemicals (PFOS, PFOA and PFHxS) to the estuarine sediments and organic carbon (OC) content with r² values ranging from 0.87 to 0.91. The nature of the constituents of OC was determined by nuclear magnetic resonance (NMR) for a subset (10) of the sediments to assess whether the strong relationship between sorption and OC was due solely to an increasing amount of OC or to particular OC fractions. The NMR analysis could not provide strong evidence for one OC fraction type explaining the variation in sorption of the three PFASs. Further investigation using partial least squares of the whole spectra also did not show any particular OC components could explain the K_d variation. This data suggests that variation in sorption in these sediments was primarily due to the varying OC content and not its chemistry.

Keywords: Organic carbon; PFHxS; PFOA; PFOS; Sorption.