| 1. |
- Cousins, Ian, et al.
(författare)
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Outside the Safe Operating Space of a New Planetary Boundary for Per- and Polyfluoroalkyl Substances (PFAS)
- 2022
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 56:16, s. 11172-11179
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Tidskriftsartikel (refereegranskat)abstract
- It is hypothesized that environmental contamination by per- and polyfluoroalkyl substances (PFAS) defines a separate planetary boundary and that this boundary has been exceeded. This hypothesis is tested by comparing the levels of four selected perfluoroalkyl acids (PFAAs) (i.e., perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), and perfluorononanoic acid (PFNA)) in various global environmental media (i.e., rainwater, soils, and surface waters) with recently proposed guideline levels. On the basis of the four PFAAs considered, it is concluded that (1) levels of PFOA and PFOS in rainwater often greatly exceed US Environmental Protection Agency (EPA) Lifetime Drinking Water Health Advisory levels and the sum of the aforementioned four PFAAs (Σ4 PFAS) in rainwater is often above Danish drinking water limit values also based on Σ4 PFAS; (2) levels of PFOS in rainwater are often above Environmental Quality Standard for Inland European Union Surface Water; and (3) atmospheric deposition also leads to global soils being ubiquitously contaminated and to be often above proposed Dutch guideline values. It is, therefore, concluded that the global spread of these four PFAAs in the atmosphere has led to the planetary boundary for chemical pollution being exceeded. Levels of PFAAs in atmospheric deposition are especially poorly reversible because of the high persistence of PFAAs and their ability to continuously cycle in the hydrosphere, including on sea spray aerosols emitted from the oceans. Because of the poor reversibility of environmental exposure to PFAS and their associated effects, it is vitally important that PFAS uses and emissions are rapidly restricted.
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| 2. |
- Savvidou, Eleni Konstantina, 1994-, et al.
(författare)
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Horizontal and Vertical Distribution of Perfluoroalkyl Acids (PFAAs) in the Water Column of the Atlantic Ocean
- 2023
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Ingår i: Environmental Science and Technology Letters. - : AMER CHEMICAL SOC. - 2328-8930. ; 10:5, s. 418-424
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Tidskriftsartikel (refereegranskat)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 similar to 50 degrees N to similar to 50 degrees 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 sigma PFAA 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 longer-chain 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.
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| 3. |
- Sha, Bo, 1987-, et al.
(författare)
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Enrichment of Perfluoroalkyl Acids on Sea Spray Aerosol in Laboratory Experiments : The Role of Dissolved Organic Matter, Air Entrainment Rate and Inorganic Ion Composition
- 2024
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Ingår i: Environmental Science and Technology Letters. - 2328-8930.
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Tidskriftsartikel (refereegranskat)abstract
- The process by which perfluoroalkyl acids (PFAAs) become enriched on sea spray aerosol (SSA) is complex and likely influenced by several factors. In this study, we utilized a plunging water jet in a controlled laboratory setup to generate SSA. We investigated the enrichment process of PFAAs on nascent SSA by systematically varying three key parameters: 1) total organic carbon (TOC), 2) water jet flow rate, and 3) inorganic ion composition. The results showed a significant enhancement in enrichment when organic matter was introduced into artificial seawater. However, this enhancement did not exhibit a consistent trend when increasing the TOC from 1 to 2 mg L-1. The enrichment was increased at higher water jet flow rates (3.2 L min(-1)) compared to lower flow rates (1.6 and 2.4 L min(-1)), and the effect was particularly pronounced for submicrometer SSA particles. There was minimal difference in the enrichment of PFAAs when SSA was generated using sodium chloride solution instead of artificial seawater at the same salinity. Overall, these findings shed light on the complex process of PFAA enrichment on SSA and improved our understanding of the uncertainties associated with varying dissolved organic matter, water jet flow rate, and inorganic ion composition.
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| 4. |
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| 5. |
- Sha, Bo, 1987-
(författare)
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Transport of perfluoroalkyl acids from the ocean to the atmosphere via sea spray aerosol
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Perfluoroalkyl acids (PFAAs) are a subgroup of per- and polyfluoroalkyl substances (PFAS) that have been widely used in commercial and industrial applications. PFAAs are very persistent in the environment and some can bioaccumulate and have adverse health effects on human health. They have been detected ubiquitously in the abiotic environment, in biota and in humans. Long-range atmospheric transport (LRAT) is considered important for their global distribution. PFAAs are detected in the global oceans and they can be enriched in sea spray aerosol (SSA) due to their high surface activity. Thus, ocean-to-atmosphere transfer via sea spray aerosol emission is suggested to be one of the major sources of PFAAs to the atmosphere, yet the contribution of this source to PFAAs in air is not well-understood. The aim of this thesis is to improve the knowledge regarding the importance of SSA as a global source of PFAAs in the atmosphere. In Paper I, PFAA enrichment on SSA particles of different sizes was investigated via a series of laboratory experiments. A sea spray simulation chamber filled with sodium chloride solution (~35 g L-1) was used to generate SSA. The results showed that variation in PFAA water concentrations had little impact on the SSA enrichment factors (EFs). Furthermore, the results suggested that SSA production mechanisms result in different enrichment behaviors of individual PFAAs on <1 µm and >1µm SSA particles. Paper II provided clear field evidence that SSA can be an important source of PFAAs in the atmosphere. Significant positive correlations (p<0.05) were identified between the concentrations of PFAAs and SSA tracer ion (i.e. Na+) in aerosol samples collected at two Norwegian coastal sites during long-term air monitoring. Such correlations suggested that PFAAs transported via SSA can have a significant influence on their air concentrations in coastal areas. Aiming at bridging the gap between the lab and the field, in Paper III, a series of field experiments were conducted along a transect from ~50°N to ~50°S on the Atlantic Ocean. Changes in surface seawater temperature, salinity, conductivity and fluorescence during the field experiments revealed minor influences on EFs. However, the EFs derived from the field experiments were higher than the lab experiments in Paper I, which may be due to the different composition and properties of the chamber water in the two studies. It was concluded, however, that the variation of PFAA concentrations in the global oceans is the major contributor to the uncertainty in the estimation of PFAA ocean-to-air flux via SSA emission. Paper IV investigated mass-size distributions of PFAAs in aerosol samples collected near an industrial source and the associated LRAT potential of the PFAAs emitted. The results suggested that industrial sources can have regional influence on PFAA concentration in air. The information in Paper IV will help evaluate the relative importance of atmospheric sources of PFAAs at certain locations. This thesis contributes to a better understanding on the transport of PFAAs via SSA emission and on the sources of PFAAs to air in general.
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| 6. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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