Horizontal and Vertical Distribution of Perfluoroalkyl Acids (PFAAs) in the Water Column of the Atlantic Ocean

Abstract

Perfluoroalkyl acids (PFAAs) are widely distributed in the oceans which are their largest global reservoir, but knowledge is limited about their vertical distribution and fate. This study measured the concentrations of PFAAs (perfluoroalkyl carboxylic acids (PFCAs) with 6 to 11 carbons and perfluoroalkanesulfonic acids (PFSAs) with 6 and 8 carbons) in the surface and deep ocean. Seawater depth profiles from the surface to a 5000 m depth at 28 sampling stations were collected in the Atlantic Ocean from ∼50°N to ∼50°S. The results demonstrated PFAA input from the Mediterranean Sea and the English Channel. Elevated PFAA concentrations were observed at the eastern edge of the Northern Atlantic Subtropical Gyre, suggesting that persistent contaminants may accumulate in ocean gyres. The median ΣPFAA surface concentration in the Northern Hemisphere (n = 17) was 105 pg L −1 , while for the Southern Hemisphere (n = 11) it was 28 pg L −1 . Generally, PFAA concentrations decreased with increasing distance to the coast and increasing depth. The C6−C9 PFCAs and C6 and C8 PFSAs dominated in surface waters, while longerchain PFAAs (C10−C11 PFCAs) peaked at intermediate depths (500−1500 m). This profile may be explained by stronger sedimentation of longer-chain PFAAs, as they sorb more strongly to particulate organic matter.

PFAS occurrence and distribution in yard waste compost indicate potential volatile loss, downward migration, and transformation

“…The distribution of long-chain PFAS is influenced by both moisture and DOM in the solid medium. 49,61–67 Interestingly, DOM at 2 ft depth (7.82–14.21 g kg −1 ) was significantly ( α ≤ 0.05) greater than the DOM at the compost surface (3.57–4.78 g kg −1 ), showing a strong correlation with the total PFAS at varying depths (Tables S12, S13 and Fig. S5†).…”

Water Analysis: Emerging Contaminants and Current Issues

“…The horizontal and vertical distribution of perfluoroalkyl acids (PFAAs) in the water column of the Atlantic Ocean was the focus of a study by Savvidou et al, who used SPE with LC-HRMS to measure 12 PFAS at 28 sampling stations extending from Europe to South America . Results showed PFAA input from the Mediterranean Sea and the English Channel, with elevated levels in ocean gyres.…”

Accumulation of Per- and Polyfluoroalkyl Substances (PFAS) in Coastal Sharks from Contrasting Marine Environments: The New York Bight and The Bahamas

“…The first study reporting PFAS concentrations in wildlife, including marine species such as tunas and marine mammals, confirmed the ubiquitous distribution of PFAS worldwide. , Over the past two decades, a number of studies have reported on the occurrence of PFAS in seawater and marine biota, including plankton, fish, and marine mammals. − Longer chain PFAS are associated with high rates of bioaccumulation, ,− driving elevated PFAS concentrations in higher-order and long-lived consumers – this offers a direct exposure route to humans through diet . Ocean environments are often referred to as the “ultimate sink” of many anthropogenic contaminants, including PFAS.…”