Perfluoroalkylated Substances in the Global Tropical and Subtropical Surface Oceans

Abstract

In this study, perfluoroalkylated substances (PFASs) were analyzed in 92 surface seawater samples taken during the Malaspina 2010 expedition which covered all the tropical and subtropical Atlantic, Pacific and Indian oceans. Nine ionic PFASs including C6−C10 perfluoroalkyl carboxylic acids (PFCAs), C4 and C6−C8 perfluoroalkyl sulfonic acids (PFSAs) and two neutral precursors perfluoroalkyl sulfonamides (PFASAs), were identified and quantified. The Atlantic Ocean presented the broader range in concentrations of total PFASs (131−10900 pg/L, median 645 pg/L, n = 45) compared to the other oceanic basins, probably due to a better spatial coverage. Total concentrations in the Pacific ranged from 344 to 2500 pg/ L (median = 527 pg/L, n = 27) and in the Indian Ocean from 176 to 1976 pg/L (median = 329, n = 18). Perfluorooctanesulfonic acid (PFOS) was the most abundant compound, accounting for 33% of the total PFASs globally, followed by perfluorodecanoic acid (PFDA, 22%) and perfluorohexanoic acid (PFHxA, 12%), being the rest of the individual congeners under 10% of total PFASs, even for perfluorooctane carboxylic acid (PFOA, 6%). PFASAs accounted for less than 1% of the total PFASs concentration. This study reports the ubiquitous occurrence of PFCAs, PFSAs, and PFASAs in the global ocean, being the first attempt, to our knowledge, to show a comprehensive assessment in surface water samples collected in a single oceanic expedition covering tropical and subtropical oceans. The potential factors affecting their distribution patterns were assessed including the distance to coastal regions, oceanic subtropical gyres, currents and biogeochemical processes. Field evidence of biogeochemical controls on the occurrence of PFASs was tentatively assessed considering environmental variables (solar radiation, temperature, chlorophyll a concentrations among others), and these showed significant correlations with some PFASs, but explaining small to moderate percentages of variability. This suggests that a number of physical and biogeochemical processes collectively drive the oceanic occurrence and fate of PFASs in a complex manner.

Simultaneous qualitative and quantitative analysis of fluoroalkyl sulfonates in riverine water by liquid chromatography coupled with Orbitrap high resolution mass spectrometry

“…A range of 0.03-89 ng/L PFOS was detected in river water of eastern China [4]. In Atlantic, Indian and Pacific oceans, PFBS, PFHxS and PFOS occurred in a range of 20.0-45.4 pg/L, 6.65-32.4 pg/L and 88. pg/L respectively [5]. PFOS was also found in Tibetan Mountain with a concentration range of 25.0-64.2 pg/L in surface snow and 61.4-346 pg/L in snow core [6].…”

“…The full scan mass range was set at 200-700 m/z with a resolution of 120,000 (FWHM at 200 m/z). Automatic gain control (AGC) target was assigned a value of 1.0e 5 (maximum number of ions filling C-Trap) with a maximum injection time of 100 ms. For dd-MS 2 scan, precursor ion selection range was limited at 250-650 m/z with a mass tolerance of 0.5 m/z and quadrupole isolated the precursor ions with an isolation window of 1 m/z. Only those precursor ions that had a signal threshold >1.0e 4 counts were permissible for MS 2 fragmentation activation with 40% collision energy.…”

“…The wide usages of the chemicals in industry and daily necessities, such as surfactants, textile, aqueous fire-forming foam, mist suppressant and coatings, have resulted in their inevitable release into the environment since 1950s [2]. Particularly, linear and branched perfluorooctane sulfonate (PFOS) isomers as well as other perfluoroalkyl sulfonate analogs (PFSAs) have become world-wide contaminants due to the persistent and long-range transport characteristics as well as their ubiquitous presence in aqueous environmental com-partments [3][4][5][6][7]. For example, perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS) and PFOS were present with a concentration ranged of 0.94-13.7 ng/L in Taihu Lake [3].…”

“…Generally, quantitative analysis is performed by monitoring the transition between precursor ion and one of the fragmentation ions, while analyte identification is conducted by verifying the ratio of two fragmentation ions. The LC-ESI-MS/MS methods are competent for the trace analysis of PFSAs with low limits of detection (LODs) in a range of 0.06-1000 pg/L [11], which covers the residue levels of PFSA homologues in various kinds of environmental medium [5,12,13]. However, accurate quantitative analysis of total PFOS isomers ( PFOS) by the LC-ESI-MS/MS method is still a challenge.…”

North Atlantic Deep Water formation inhibits high Arctic contamination by continental perfluorooctane sulfonate discharges

“…. Surface PFOS measurements are fromAhrens et al [2009aAhrens et al [ , 2009bAhrens et al [ , 2010b;Benskin et al [2012],Gonzalez-Gaya et al [2014], andZhao et al [2012]. Surface PFOS measurements are fromAhrens et al [2009aAhrens et al [ , 2009bAhrens et al [ , 2010b;Benskin et al [2012],Gonzalez-Gaya et al [2014], andZhao et al [2012].…”