Influence of Environmental Factors on the Fate of Legacy and Emerging Per- and Polyfluoroalkyl Substances along the Salinity/Turbidity Gradient of a Macrotidal Estuary

Abstract

This study aimed at bridging knowledge gaps regarding the land-sea transport of per- and polyfluoroalkyl substances (PFASs) through riverine discharge into coastal waters. The present survey was conducted in the Gironde estuary (southwestern France) where PFASs were ubiquitously detected albeit at low levels. Emerging PFASs such as fluorotelomer sulfonates or polyfluoroalkyl phosphate diesters accounted for a relatively minor proportion of ∑PFASs, while perfluorooctanesulfonate, perfluorohexanesulfonate, and perfluorohexanoate were the predominant congeners. Multiple linear regressions provided insights into the relative influence of factors controlling PFAS sediment levels. In that respect, the organic carbon fraction (strongly correlated to sediment grain size) appeared as a more important controlling factor than black carbon or distance from upstream sources for long-chain perfluoroalkyl acids. In the maximum turbidity zone (suspended solids up to 2600 mg L), the particle-associated fraction was almost consistently >50% for long-chain perfluoroalkyl carboxylates and sulfonates (≥C8 and ≥ C6, respectively). Empirical models of K partitioning coefficients were derived by integrating, for the first time, both particle-concentration and salting-out effects. These results represent significant progress toward the development of numerical transport models integrating both PFAS partitioning and 3D-hydrosedimentary dynamics, with a view to estimate PFAS mass budgets at the land-sea interface.

Temporal variations of perfluoroalkyl substances partitioning between surface water, suspended sediment, and biota in a macrotidal estuary

“…The 6:2 fluorotelomer sulfonate (6:2 FTSA) was also recurrently detected (75%). Occurrence data are in agreement with a 2014 survey conducted at large spatial scale in this estuary (Munoz et al 2017b). The median ∑PFASs was 6.2 ng L -1 , close to the 7.9 ng L -1 median reported at French nationwide scale for 133 rivers and lakes (Munoz et al, 2015).…”

Dietary bioaccumulation of persistent organic pollutants in the common sole Solea solea in the context of global change. Part 2: Sensitivity of juvenile growth and contamination to toxicokinetic parameters uncertainty and environmental conditions variability in estuaries

“…PFOS is known to be mainly associated with the particulate phase in estuarine environment, which reduces exposure via respiration (Munoz et al, 2017b). Another likely source of uptake might be considered for PFOS: the biotransformation of precursors, themselves accumulated from the environment (Babut et al, 2017;Martin et al, 2010).…”

“…First, it is one of the largest European estuaries (Lobry et al, 2003), and thus, one of the main nursery ground for the Atlantic sole stock, which is one of the most economically important fish stock for the Bay of Biscay (Le Pape et al, 2003). Second, abiotic and biotic contamination has been studied for several years for PCBs (Bodin et al, 2014;Lauzent, 2018;Tapie et al, 2011) and more recently for PFASs (Munoz et al, 2017b(Munoz et al, , 2017a. Third, significant changes in the abundance of flatfish populations (Hermant et al, 2010;Pasquaud et al, 2012) and in the structure and functioning of the whole food web (Chevillot et al, 2016; in relation with strong modifications of physicochemical conditions (warming and salinization) were recently highlighted (Chaalali et al, 2013a).…”

Combined spatial and retrospective analysis of fluoroalkyl chemicals in fluvial sediments reveal changes in levels and patterns over the last 40 years

“…Sediment samples (1 g dry weight, dw) were spiked with ISs and extracted by microwave-assisted extraction with methanol (5 min at 70°C) using a Start E Milestone system (Munoz et al, 2017a). Extracts were filtered through a polyethylene frit (20 µm) and concentrated to 1 mL under a nitrogen stream.…”