Polyfluoroalkyl Substances In Sediment Research Articles

Contamination status, partitioning behavior, ecological risks assessment of legacy and emerging per- and polyfluoroalkyl substances in a typical heavily polluted semi-enclosed bay, China

The contaminant status, spatial distribution, partitioning behavior, and ecological risks of 26 legacy and emerging perfluoroalkyl and polyfluoroalkyl substances (PFASs) in Laizhou Bay, China were investigated. The concentrations of ∑PFASs in surface and bottom seawater ranged from 37.2 to 222 ng/L and from 34.2 to 305 ng/L with an average of 116 ± 62.7 and 138 ± 93.8 ng/L, respectively. There were no significant differences in the average concentrations between the surface and bottom seawater (P > 0.05). Perfluorooctanoic acid (PFOA) and short-chain PFASs dominated the composition of PFASs in seawater. The concentrations of ∑PFASs in sediments ranged from 0.997 to 7.21 ng/g dry weight (dw), dominated by perfluorobutane sulfonate (PFBS), perfluorobutanoic acid (PFBA), and long-chain PFASs. The emerging alternatives of perfluoro-1-butane-sulfonamide (FBSA) and 6:2 fluorotelomer sulfonic acid (6:2 FTSA) were detected for the first time in Laizhou Bay. The ∑PFASs in seawater in the southwest of the bay were higher than those in the northeast of the bay. The ∑PFASs in sediments in the northeast sea area were higher than those in the inner area of the bay. Log Kd and log Koc values increased with increasing carbon chain length for PFASs compounds. Ecological risk assessments indicated a low ecological risk associated with HFPO-DA but a moderate risk associated with PFOA contamination in Laizhou Bay. Positive matrix factorization (PMF) analysis revealed that fluoropolymer manufacturing, metal plating plants, and textile treatments were identified as major sources contributing to PFASs contamination.

Sedimentary records of contaminant inputs in Frobisher Bay, Nunavut

Contaminants, such as polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), heavy metals, and per and polyfluoroalkyl substances (PFASs), primarily reach the Arctic through long-range atmospheric and oceanic transport. However, local sources within the Arctic also contribute to the levels observed in the environment, including legacy sources and new sources that arise from activities associated with increasing commercial and industrial development. The City of Iqaluit in Frobisher Bay, Nunavut (Canada), has seen rapid population growth and associated development during recent decades yet remains a site of interest for ocean protection, where Inuit continue to harvest country food. In the present study, seven dated marine sediment cores collected in Koojesse Inlet near Iqaluit, and from sites in inner and outer Frobisher Bay, respectively, were analyzed for total mercury (THg), major and trace elements, PAHs, PCBs, and PFASs. The sedimentary record in Koojesse Inlet shows a period of Aroclor 1260-like PCB input concurrent with military site presence in the 1950–60s, followed by decades of input of pyrogenic PAHs, averaging about ten times background levels. Near-surface sediments in Koojesse Inlet also show evidence of transient local-source inputs of THg and PFASs, and recycling or continued slow release of PCBs from legacy land-based sources. Differences in PFAS congener composition clearly distinguish the local sources from long-range transport. Outside Koojesse Inlet but still in inner Frobisher Bay, 9.2 km from Iqaluit, sediments showed evidence of both local source (PCB) and long-range transport. In outer Frobisher Bay, an up-core increase in THg and PFASs in sediments may be explained by ongoing inputs of these contaminants from long-range transport. The context for ocean protection and country food harvesting in this region of the Arctic clearly involves both local sources and long-range transport, with past human activities leaving a long legacy insofar as levels of persistent organic pollutants are concerned.

Analysis of a Passive Sampling Device to Assess the Behavior of Per- and Polyfluoroalkyl Substances in Sediments.

Per- and polyfluoroalkyl substances (PFAS) are an emerging class of compounds that cause health and environmental problems worldwide. In aquatic environments, PFAS may bioaccumulate in sediment organisms, which can affect the health of organisms and ecosystems. As such, it is important to develop tools to understand their bioaccumulation potential. In the present study, the uptake of perfluorooctanoic acid (PFOA) and perfluorobutane sulfonic acid (PFBS) from sediments and water was assessed using a modified polar organic chemical integrative sampler (POCIS) as a passive sampler. While POCIS has previously been used to measure time-weighted concentrations of PFAS and other compounds in water, in our study, the design was adapted for analyzing contaminant uptake and porewater concentrations in sediments. The samplers were deployed into seven different tanks containing PFAS-spiked conditions and monitored over 28 days. One tank contained only water with PFOA and PFBS, three tanks contained soil with 4% organic matter, and three tanks contained soil combusted at 550 °C to minimize the influence of labile organic carbon. The uptake of PFAS from the water was consistent with previous research using a sampling rate model or simple linear uptake. For the samplers placed in the sediment, the uptake process was explained well using a mass transport based on the external resistance from the sediment layer. Uptake of PFOS in the samplers occurred faster than that of PFOA and was more rapid in the tanks containing the combusted soil. A small degree of competition was observed between the two compounds for the resin, although these effects are unlikely to be significant at environmentally relevant concentrations. The external mass transport model provides a mechanism to extend the POCIS design for measuring porewater concentrations and sampling releases from sediments. This approach may be useful for environmental regulators and stakeholders involved in PFAS remediation. Environ Toxicol Chem 2023;00:1-13. © 2023 SETAC.

Solvent-Free Nonthermal Destruction of PFAS Chemicals and PFAS in Sediment by Piezoelectric Ball Milling.

Studies on the destruction of solid per- and polyfluoroalkyl substances (PFAS) chemicals and PFAS-laden solid wastes significantly lag behind the urgent social demand. There is a great need to develop novel treatment processes that can destroy nonaqueous PFAS at ambient temperatures and pressures. In this study, we develop a piezoelectric-material-assisted ball milling (PZM-BM) process built on the principle that ball collisions during milling can activate PZMs to generate ∼kV potentials for PFAS destruction in the absence of solvents. Using boron nitride (BN), a typical PZM, as an example, we successfully demonstrate the complete destruction and near-quantitative (∼100%) defluorination of solid PFOS and perfluorooctanoic acid (PFOA) after a 2 h treatment. This process was also used to treat PFAS-contaminated sediment. Approximately 80% of 21 targeted PFAS were destroyed after 6 h of treatment. The reaction mechanisms were determined to be a combination of piezo-electrochemical oxidation of PFAS and fluorination of BN. The PZM-BM process demonstrates many potential advantages, as the degradation of diverse PFAS is independent of functional group and chain configurations and does not require caustic chemicals, heating, or pressurization. This pioneering study lays the groundwork for optimizing PZM-BM to treat various PFAS-laden solid wastes.

Assessing per- and polyfluoroalkyl substances (PFAS) in sediments and fishes in a large, urbanized estuary and the potential human health implications

The primary source of chronic exposures to per- and polyfluoroalkyl substances (PFASs) in humans is through the ingestion of contaminated foods and drinking water, with fish and other seafood being a major contributor. Nevertheless, there is scant literature on the dietary exposure to PFASs for the general United States (U.S.) population. The Tampa Bay (Florida, USA) region has the highest population density in the State and communities and their attendant support services are arrayed in an urban to semi-rural continuum from the head of the Bay to the ocean mouth. Tampa Bay supports productive recreational and commercial fisheries, providing a diverse community of species. A variety of potential PFAS sources surround Tampa Bay including airports, industry, wastewater treatment plants, fire-fighting training areas and military installations. The objective of this study is to quantify PFASs in sediment and fishes collected from Tampa Bay to further estimate human health risks from dietary exposures. Sediment (n = 17) and fish (24 species, n = 140) were collected throughout Tampa Bay in 2020 and 2021 and analyzed for 25 PFAS compounds. Concentrations of PFASs in sediments and edible tissues of fish ranged from 36.8 to 2,990 ng kg-1 (dry weight) and 307 to 33,600 ng kg-1 (wet weight), respectively. Generally, levels were highest in Old Tampa Bay and decreased south towards the Gulf of Mexico. Profiles in both matrices were generally dominated by perfluorooctane sulfonic acid (PFOS) with variations by location. Estimated human health risks from the consumption of contaminated fish collected in Tampa Bay exceeded concentration thresholds for minimum risk levels (MRLs) and tolerable weekly intake (TWIs) values for adults and youths. Additionally, concentrations of PFOS in edible fish tissues of several recreationally important species collected in Tampa Bay exceeded consumption guideline levels established by several governmental agencies. In the current context, the elevated levels of PFAS in Tampa Bay and the exceedances of available thresholds for potential human health risks are a cause for concern and justify a more intensive examination especially for more heavily utilized species, particularly those used in subsistence-level fishing, which, as elsewhere may be significantly under documented.

Per- and poly-fluoroalkyl substances in sediments from the water-level-fluctuation zone of the Three Gorges Reservoir, China: Contamination characteristics, source apportionment, and mass inventory and loadings

Sixteen paired surface sediment samples (0–5 cm, n = 32) covering upstream to downstream of water-level-fluctuation zone of Three Gorges Reservoir, China were collected in March 2018 (following six months of submergence) and September 2018 (after six months of exposure). Seventeen per- and poly-fluoroalkyl substances (PFASs) were quantified to evaluate contamination characteristics, apportion source categories and estimate mass inventory and loadings. The concentration of ΣPFASs ranged from 0.26 to 0.82 ng·g−1 at high water-level (HWL) and 0.46–1.53 ng·g−1 at low water-level (LWL). Perfluorooctanoic acid (PFOA, mean: 0.32 ng·g−1) and perfluorooctane sulfonate (PFOS, mean: 0.12 ng·g−1) dominated, accounting 44.9% and 16.3% of the total PFASs, respectively. The distribution of PFASs was more influenced by anthropogenic activities than physicochemical parameters of the sediments. Positive matrix factorization (PMF) identified PFOA-based products was the major sources (40.1% and 38.6%, respectively). Besides, the direct sources of PFOA-, PFOS-, PFNA-and PFBA-based products played the predominant role, while the indirect degradation of precursors contributed relatively little. The sediment (0–5 cm) mass inventory of PFASs at LWL (57.5 kg) was higher than HWL (39.3 kg). The annual mass loadings of the total PFASs, PFOA, PFOS, perfluoroundecanoic acid (PFUdA) and perfluorononanoic acid (PFNA) from the upstream to the middle-lower reaches of Yangtze River were 27.4 kg, 11.1 kg, 4.63 kg, 2.89 kg and 2.57 kg, respectively. This study could provide the basic datasets of PFASs in surface sediments of the TGR, and also indicate an important transport of PFASs from upstream to the lower reaches, which should be further studied as well.

Distribution of legacy and emerging per- and polyfluoroalkyl substances in riverine and coastal sediments of Southeastern North Carolina, USA.

The sediment distribution of per- and polyfluoroalkyl substances (PFAS) along a river to ocean transect was investigated. Samples were collected between September 2017 and October 2019 with targeted quantification of six legacy and replacement PFAS by LC-MS/MS. Total PFAS concentrations ranged from below the LOQ to 7.47 ng per g dry weight with PFOA, PFOS, HFPO-DA and PFMOAA the most frequently detected. Significant correlations (p < 0.05) were found between PFOS and HFPO-DA sedimentary concentration and percent organic carbon (% OC); however, PFOA and PFMOAA were not correlated with sediment % OC. This study highlights the occurrence of the replacement PFAS in sediments for the first time. Sediment extracts were screened for 18 additional PFAS compounds by high resolution mass spectrometry. A series of perfluorinated ether carboxylic acid and perfluorinated ether sulfonic acid with either one or two acidic functional groups were detected at various locations in the upper portion of the Cape Fear River. A series of chromatographically resolved isomers (C7F13O5S1; M-1) were detected and may be Nafion™ degradation products.

Occurrence, Profile, and Potential Risks of Novel and Legacy Polyfluoroalkyl Substances in Bullfrogs: Pilot Study in an Intensive Aquaculture Region, China

Per- and polyfluoroalkyl substances (PFASs) have captured worldwide attention due to their persistent and bioaccumulative characteristics. The bullfrog is a highly nutritious and edible aquatic product, but the PFAS accumulation characteristics of bullfrogs had not been paid attention. The present study analyzed the PFAS concentrations in different tissues of cultured bullfrogs and relevant water and sediments collected from the aquaculture region in the coastal area of South China. Results showed that total PFAS concentrations were 50.26–364.25 ng/L in water, with a mean of 135.58 ng/L; concentrations in effluent water were significantly higher than those in influent water, which means bullfrog farming could increase contaminants into the surroundings. The total PFAS concentrations varied from 2.89 to 162.26 ng/g·dw in sediment. The distribution profile of PFASs in sediment was similar to that of water, with short chain playing a significant role. Total PFASs in bullfrog tissues were 3.36–84.07 ng/g·dw, with the highest values in the digestive system (intestines and stomach). As for one novel PFAS alternative, chlorinated polyfluorinated ether sulfonate (F-53B) was found at high detectable levels in all habitat samples and had a higher value of logarithmic bioaccumulation factors. The estimated dietary intake (EDI) for residents in the study area was generally higher than that in other regions; however, the hazard ratios (HRs) for most detected PFASs were far below the safety threshold value “1.” These results suggest that frequent consumption of these bullfrogs would basically not cause severe health effects on local residents in terms of PFASs.

Occurrence, partitioning behavior and risk assessments of per- and polyfluoroalkyl substances in water, sediment and biota from the Dongshan Bay, China

Twenty-five per- and polyfluoroalkyl substances (PFASs) were analyzed in water, sediment and biota from the Dongshan Bay (DSB) to study their seasonal variations, composition profiles, potential pollution sources, partitioning behavior and risk assessments. The total concentrations of PFASs (∑PFASs) in water ranged from 3.2 to 6.5 ng L−1 (mean 4.0 ng L−1) during the dry season, and 0.11–4.5 ng L−1 (mean 1.3 ng L−1) during the wet season. Perfluoro-butane sulfonic acid (PFBS), perfluoro-butanoic acid (PFBA) and perfluoro-octanoic acid (PFOA) were dominated and frequently detected in water. ∑PFASs in sediment were 0.15–0.37 ng g−1 dw (mean 0.24 ng g−1 dw) with the long-chain PFASs perfluoro-octane sulfonic acid (PFOS) dominating. High concentrations of PFASs in land-based drainage outlets (2.0–384.6 ng L−1 in water) and Zhangjiang estuary indicated that land-based discharges and the river discharge were the main sources. High concentration (366.1 ng L−1) and proportion (94%) of PFBA on one drainage outlet agreed with the trend that PFBA was as an alternative to long-chain PFASs. ∑PFASs in biota ranged from 0.11 to 0.40 ng g−1 ww, and only long-chain PFASs were detected. The partition coefficients (log Kd) of PFASs between water and sediment ranged from 1.13 to 2.90, increased with carbon chain length, implied long-chain PFASs are more likely to adsorb to sediment. Results of ecological and health risk assessments indicated that PFASs had no significant risk for the aquatic organisms and local residents.

Distribution, partitioning behavior and potential source of legacy and alternative per- and polyfluoroalkyl substances (PFASs) in water and sediments from a subtropical Gulf, South China Sea

Legacy per- and polyfluoroalkyl acids (PFASs) have received global concern over the scientific and public community since this century. However, the information on alternative PFASs pollution in the marine environment, especially in the subtropical marine environment is extremely limited. This study investigated the occurrence, partitioning, potential sources, and ecological risks of PFASs, including perfluoroalkane sulfonic acids (PFSAs), perfluoroalkyl carboxylic acids (PFCAs), and alternative PFASs, in surface water and sediments from the subtropical Beibu Gulf, South China. Concentrations of total PFASs (∑PFASs) were in the range of 0.98–2.64 ng/L in water and 0.19–0.66 ng/g (dry weight, dw) in sediment, respectively. Perfluorooctanoic acid (PFOA) was the most abundant PFAS in water, while PFASs in sediment were dominated by perfluorooctanesulfonic acid (PFOS) and PFOA. Among investigated environmental parameters (total organic carbon (TOC), grain size, water pH, sediment pH, and salinity), TOC and salinity were the dominant factors influencing the sediment-water distribution coefficient (Kd) of PFOA, perfluorodecanoic acid (PFDA), and perfluorononanoic acid (PFNA). Log Kd and log soil organic carbon-water distribution coefficient (Koc) both increase with increasing carbon chain length of PFASs. Significantly positive correlations between PFOS and perfluorohexanoic acid (PFHxA) (p < 0.05), PFOA and perfluoro-1-butane-sulfonamide (FBSA) were observed, suggesting that these PFASs might have similar sources and transport routes. Preliminary environmental risk assessment showed that PFOA and PFOS would not pose risks to the marine aquatic environment. This is the first comprehensive survey of legacy and alternative PFASs in a subtropical area of the Beibu Gulf, which provides significant data and scientific basis to better understand the fate of PFASs and pollution control management.

Distribution Characteristics of Per-/polyflouralkyl Substances in River Sediments Around Typical Fluorine Industrial Parks

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are a group of manmade chemicals and are ubiquitously detected in aquatic environments. China is a major producer and consumer of PFASs. In this study, we investigated the occurrence and characteristics of PFASs in the surface sediments from three fluorine industrial parks in North China, the Xihe River in Liaoning Province (Fuxin Section), the Xiaoqing River in Shandong Province (Zibo Section), and the Yangtze River in Jiangsu Province (Changshu Section), using the UPLC/MS-MS method. The total concentration of PFASs (∑PFASs) in surface sediments of the Xihe River ranged from 15.8 to 2770 ng ·g-1, and PFTeDA and HFPO-DA were the dominant pollutants. In the surface sediments of the Xiaoqing River, ∑PFASs ranged from 12.2 to 7853 ng ·g-1, and PFOA and HFPO-DA were the dominant pollutants. In the surface sediments of the Yangtze river, ∑PFASs ranged from 9.20 to 35.9 ng ·g-1, and PFTeDA and 6：2 FTS were the main pollutants. Sewage discharge from the industrial parks (point source pollution) was the main source of PFASs in three regions in this study. The PFAS content and composition in three regions varied significantly depending on the production capacity and industry type. There was no significant correlation between the content of PFASs and its components and the particle size and TOC of the sediments. The correlations between the components of PFASs indicated that the enrichment process of PFASs in sediments was impacted by various factors.

Legacy and alternative per- and polyfluoroalkyl substances in a subtropical marine food web from the Beibu Gulf, South China: Fate, trophic transfer and health risk assessment

The usage of alternative per- and polyfluoroalkyl substances (PFASs) has been increasing due to the restriction and elimination of legacy PFASs. However, there is limited knowledge on bioaccumulation and trophic magnification of alternative PFASs, especially in subtropical ecosystems. In the present study, we performed a comprehensive survey to investigate the occurrence, bioaccumulation and trophic magnification of legacy and alternative PFASs in subtropical marine food webs in the Beibu Gulf, South China. Results showed that perfluorobutanoic acid (PFBA) and perfluorooctanoic acid (PFOA) were the predominant PFASs in water phase, while perfluorooctane sufonate (PFOS) contributed most to the sum of target PFASs in sediments and marine organisms. Of the investigated PFASs, PFOS and 6:2 chlorinated polyfluoroalkyl ether sulfonic acids (F-53B) exhibited the highest bioaccumulation factor with values > 5000, qualifying as very bioaccumulative chemicals. There was a significant positive correlation between log BSAF and the carbon chain length of perfluoroalkyl carboxylic acids (PFCAs). Trophic magnification (TMF) was observed for PFOS and F-53B, while the remaining PFASs were biodiluted through the present food web. The hazard ratios for PFOS and PFOA in all organisms were far less than unity, suggesting overall low PFAS risks for humans through consumption of marine organisms.

Identification of contaminants of emerging concern with potential environmental risk in Spanish continental shelf sediments

The distribution of per- and polyfluoroalkyl substances (PFAS), alkylphenols, organotin compounds, phthalates, alkylated polycyclic aromatic hydrocarbons, current-use pesticides (CUPs) and personal care products (PCPs) was characterized in 29 surface sediments from two Spanish Iberian continental shelf areas (14 on the Atlantic and 15 on the Mediterranean coasts). Concretely, 115 organic contaminants were determined and a specific methodology was used for each contaminant group, including contaminants of emerging concern (CECs) and traditional ones, such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorinated pesticides (OCPs). PAHs, alkylated PAHs, alkylphenols and phthalates were found in all samples, showing mean concentrations per group higher than 20 ng/g (16–4974 ng/g d.w.) in the subregions under consideration (Galician, Cantabrian, Levantine-Balearic and Strait-Alboran). CUPs and PCPs were found in the majority of samples at very low concentrations of ng/g (1.4–46.8 ng/g d.w.), whereas organotins and PFAS were found principally in sediments from the Mediterranean subregions (2.5–3.9 ng/g d.w.). Different distribution patterns were observed for the contaminant groups and subregions under consideration as a consequence of the diverse predominant sources (industrial, urban, transport and agricultural activities) and environmental behavior (mainly hydrophobicity and persistence). Risk assessment confirmed the impact of phthalates, alkylphenols, PAHs and PCBs on Atlantic ecosystems and of alkylphenols, chlorpyrifos, phthalates, TBT, PAHs, OCPs and PCBs on the Mediterranean ones. Furthermore, the presence of CUPs, PCPs and PFAS in sediments from the Spanish continental shelf located between 2 and 31 km from the coast suggested that those contaminants may also provoke adverse effects on coastal marine ecosystems between their sources and their depositional areas. CapsuleAlkylphenols, phthalates and organotins may provoke adverse effects on Spanish coastal marine ecosystems from their sources to the sediment depositional areas.

Investigation of levels of perfluoroalkyl substances in surface water, sediment and fish tissue in New Jersey, USA

Per- and polyfluoroalkyl substances (PFAS) are persistent, bioaccumulative, and toxic substances found in New Jersey (NJ) due to historic and current industrial activities and the use of aqueous film forming foams. This research documents PFAS occurrence in surface water, sediments, and fish tissue at 11 targeted waterbodies in NJ suspected to be impacted by PFAS. Thirteen PFAS compounds were quantified from each media. The profile of detected PFAS differed among media from the same site, with shorter chain PFAS tending to predominate in surface water while longer chain PFAS predominated in fish and sediments. All water samples contained detectable levels of at least four perfluoroalkyl substances. PFOA, PFHpA and PFPeA were detected at every site. ΣPFAS concentrations in water samples ranged from 22.9 to 279.5 ng/L. At least one, and up to eight, PFAS were detected in sediment samples at 10 sites, while there were no detections of PFAS in sediments at the reference site. ΣPFAS concentrations in sediment samples ranged from below detection to 30.9 ng/g. At least one fish of each species at every site had detectable levels of PFAS compounds. ΣPFAS concentrations in fish were highest at sites downstream from a military facility, and lowest at the reference site. PFOS, PFDA, PFUnA and PFDoA were the predominant PFAS detected in fish tissue. PFOS was generally found in fish tissue at higher concentrations than other PFAS, with higher PFOS concentrations found in the tissue of yellow perch, American eel, pumpkinseed, and largemouth bass collected at sites with higher detections of PFOS in surface waters. PFOS levels in nearly all fish species were, on average, high enough to trigger fish consumption advisories. Additional studies are needed to further evaluate the sources and occurrence of PFAS in NJ and to better understand their movement through the environment and potential risks.

Multicompartment occurrence and partitioning of alternative and legacy per- and polyfluoroalkyl substances in an impacted river in China

Per- and polyfluoroalkyl substances (PFASs) are emerging global environmental contaminants. Exploring the occurrence and environmental behavior of PFASs in the aquatic environment is a key step in solving global fluorine chemical pollution problems. In this study, surface water, pore water, and sediment were collected from the main tributary and the middle and lower reaches of the Daling River, adjacent to the Fuxin fluorochemical manufacturing facilities in Liaoning Province in China, to elucidate the occurrence and partition behavior of PFASs. The total concentrations of PFASs ranged from 48.4 to 4578 ng/L in the overlying water, from 173 to 9952 ng/L in the pore water, and from 2.16 to 40.3 ng/g dw in the sediment fraction. Generally, perfluorobutanoic acid (PFBA) and perfluorobutane sulfonate (PFBS) were the predominant congeners in the samples, with the mean relative content fractions being almost consistently >40% in the dissolved phase and >25% in the sediment. Hexafluoropropylene oxide dimer acid (HFPO-DA) and chlorinated polyfluorinated ether sulfonic acid (6:2 Cl-PFESA) were detected, albeit at low levels. In addition, the detection frequency and the contribution of legacy long-chain PFASs in sediment were higher than those in the overlying water and pore water. Except for perfluorohexane sulfonate (PFHxS), the concentrations of the alternative PFASs in the pore water were higher than in the overlying water. The organic carbon fraction was a more important controlling factor for PFAS sediment levels than cations content. As with legacy long-chain PFASs, HFPO-DA and 6:2 Cl-PFESA tended to partition into the solid phase, whereas short-chain PFASs were readily distributed in the aqueous phase. Such research results will be helpful in modeling the transport and fate of PFASs released by point sources into coastal waters through rivers and in developing effective risk assessment and management strategies for the control of PFAS pollution.

Polyfluoroalkyl substances in Danjiangkou Reservoir, China: Occurrence, composition, and source appointment

Legacy polyfluoroalkyl substances (PFASs) have been widely detected in various environmental matrices, which has caused great public concern. This study investigated the concentration, composition, partitioning, source apportionment, estimated daily intake (EDI), and ecological risks of 18 PFASs in water and sediments from Danjiangkou Reservoir. The total PFASs concentrations were 0.46–97.94 ng/L in water and 0.07–1.62 μg/kg in sediments. The total PFASs concentrations in water followed the order of spring > summer > winter > autumn (p < 0.05), and the PFAS compositions in water also varied among four seasons. However, no seasonal differences in the concentrations and compositions of PFASs were observed in sediments. The calculated logKoc values of perfluoroalkyl carboxylic acids (PFCAs) were dependent on carbon chain length, decreasing first from C6 to C8 and then increasing from C8 to C13 due to the combined effects of steric hindrance and hydrophobic interaction, while the logKoc values of C14 and C16 PFCAs were the lowest because of their very limited use. Principal component analysis-multiple linear regression analysis (PCA-MLRA) showed that food packaging/metal plating were the main sources of PFASs in spring, autumn, and winter, accounting for 64.8–81.9% and 50.5–76.9% of the total PFASs in water and sediments, respectively. However, in summer, 68.6% of total PFASs in water originated from leather/fabrics/textiles, and 70.0% of total PFASs in sediments were derived from textile treatment agents. The total EDI values through drinking water and dermal contact were 0.85, 0.69, 0.51, and 0.47 ng/kg bw/day for children (2–6, 7–12, and 13–17 years old) and adults, respectively, which were lower than the European Food Safety Authority's tolerable daily intake. However, the detected PFASs could pose low to medium ecological risks to daphnids and fish in spring. The study was significant for the development of effective strategies for controlling PFASs pollution in the Danjiangkou Reservoir.

Occurrence and partitioning behavior of per- and polyfluoroalkyl substances (PFASs) in water and sediment from the Jiulong Estuary-Xiamen Bay, China

Twenty-four per- and polyfluoroalkyl substances (PFASs) were analyzed in water and sediment from the Jiulong Estuary-Xiamen Bay to study their seasonal variations, transport, partitioning behavior and ecological risks. The total concentration of PFASs in water ranged from 11 to 98 ng L-1 (average 45 ng L-1) during the dry season, 0.19-5.7 ng L-1 (average 1.5 ng L-1) during the wet season, and 3.0-5.4 ng g-1 dw (average 3.9 ng g-1 dw) in sediment. In water samples, short-chain PFASs were dominated by perfluorooctanoic acid (PFBA) in the dry season and perfluorobutane sulfonate (PFBS) in the wet season, while long chain PFASs, such as perfluorooctane sulfonate (PFOS), dominated in the sediment. The highest concentration of PFASs in water were found in the estuary; in contrast, the highest level of PFASs in sediment were found in Xiamen Bay. These spatial distributions of PFASs indicate that river discharge is the main source of PFASs in estuarine water, while the harbor, airport and wastewater treatment plant near Xiamen Bay may be responsible for the high PFBS and PFOS concentrations in water and sediment. The partition coefficients (log Kd) of PFASs between sediment and water (range from 1.64 to 4.14) increased with carbon chain length (R2 = 0.99) and also showed a positive relationship with salinity. A preliminary environmental risk assessment indicated that PFOS and perfluorooctanoic acid (PFOA) in water and sediment pose no significant ecological risk to organisms.

Perfluoroalkyl and polyfluoroalkyl substances in sediments from South Bohai coastal watersheds, China

This study investigated the concentrations and distribution of Perfluoroalkyl and polyfluoroalkyl substances (PFAS) in sediments of 12 rivers from South Bohai coastal watersheds. The highest concentrations of ΣPFAS (31.920ngg−1dw) and PFOA (29.021ngg−1dw) were found in sediments from the Xiaoqing River, which was indicative of local point sources in this region. As for other rivers, concentrations of ΣPFAS ranged from 0.218 to 1.583ngg−1dw were found in the coastal sediments and from 0.167 to 1.953ngg−1dw in the riverine sediments. Predominant PFAS from coastal and riverine areas were PFOA and PFBS, with percentages of 30% and 35%, respectively. Partitioning analysis showed the concentrations of PFNA, PFDA and PFHxS were significantly correlated with organic carbon. The results of a preliminary environmental hazard assessment showed that PFOS posed the highest hazard in the Mi River, while PFOA posed a relative higher hazard in the Xiaoqing River.