Do conventional cooking methods alter concentrations of per- and polyfluoroalkyl substances (PFASs) in seafood?

Investigating the partitioning behavior of per- and polyfluoroalkyl substances (PFAS) during thermal landfill leachate evaporation

Thermal landfill leachate evaporator systems can reduce the volume of leachate by up to 97%, while releasing water vapor and producing residuals (volume-reduced leachate and sludge) that are managed on-site. On-site thermal evaporators offer landfill operators leachate management autonomy without being subject to increasingly stringent wastewater treatment plant requirements. However, little is known about the partitioning of PFAS within these systems, nor the extent to which PFAS may be emitted into the environment via vapor. In this study, feed leachate, residual evaporated leachate, sludge, and condensed vapor were sampled at two active full-scale thermal landfill leachate evaporators and from a laboratory-scale leachate evaporation experiment. Samples were analyzed for 91 PFAS via ultra-high pressure liquid chromatography - tandem mass spectrometry (UHPLC-MS/MS). Similar trends were observed from Evaporator 1, Evaporator 2, and the laboratory-scale evaporator; ∑PFAS were concentrated in the residual evaporated leachate during evaporation by a factor of 5.3 to 20. All condensed vapors sampled (n = 5) contained PFAS, predominantly 5:3 fluorotelomer carboxylic acid (5:3FTCA), (full-scale vapors 729 - 4087 ng/L PFAS; lab-scale vapor 61.0 ng/L PFAS). For Evaporators 1 and 2, an estimated 9 - 24% and 10%, respectively, of the PFAS mass entering the evaporators in leachate was released with vapor during the days of sample collection. '.

Human exposure to per- and polyfluoroalkyl substances (PFAS) via the consumption of fish leads to exceedance of safety thresholds

Per- and polyfluoroalkyl substances (PFAS) receive global attention due to their adverse effects on human health and the environment. Fish consumption is a major source of human PFAS exposure. The aim of this work was to address the lack of harmonization within legislations (in the EU and the USA) and highlight the level of PFAS in fish exposed to pollution from diffuse sources in the context of current safety thresholds. A non-exhaustive literature review was carried out to obtain PFAS concentrations in wild fish from the Norwegian mainland, Svalbard, the Netherlands, the USA, as well as sea regions (North Sea, English Channel, Atlantic Ocean), and farmed fish on the Dutch market. Median sum wet weight concentrations of PFOA, PFNA, PFHxS, and PFOS ranged between 0.1 µg kg-1 (farmed fish) and 22 µg kg-1 (Netherlands eel). Most concentrations fell below the EU environmental quality standard (EQSbiota) for PFOS (9.1 µg kg-1) and would not be defined as polluted in the EU. However, using recent tolerable intake or reference dose values in the EU and the USA revealed that even limited fish consumption would lead to exceedance of these thresholds - possibly posing a challenge for risk communication.

Considerations and challenges in support of science and communication of fish consumption advisories for per- and polyfluoroalkyl substances

Federal, state, tribal, or local entities in the United States issue fish consumption advisories (FCAs) as guidance for safer consumption of locally caught fish containing contaminants. Fish consumption advisories have been developed for commonly detected compounds such as mercury and polychlorinated biphenyls. The existing national guidance does not specifically address the unique challenges associated with bioaccumulation and consumption risk related to per- and polyfluoroalkyl substances (PFAS). As a result, several states have derived their own PFAS-related consumption guidelines, many of which focus on one frequently detected PFAS, known as perfluorooctane sulfonic acid (PFOS). However, there can be significant variation between tissue concentrations or trigger concentrations (TCs) of PFOS that support the individual state-issued FCAs. This variation in TCs can create challenges for risk assessors and risk communicators in their efforts to protect public health. The objective of this article is to review existing challenges, knowledge gaps, and needs related to issuing PFAS-related FCAs and to provide key considerations for the development of protective fish consumption guidance. The current state of the science and variability in FCA derivation, considerations for sampling and analytical methodologies, risk management, risk communication, and policy challenges are discussed. How to best address PFAS mixtures in the development of FCAs, in risk assessment, and establishment of effect thresholds remains a major challenge, as well as a source of uncertainty and scrutiny. This includes developments better elucidating toxicity factors, exposures to PFAS mixtures, community fish consumption behaviors, and evolving technology and analytical instrumentation, methods, and the associated detection limits. Given the evolving science and public interests informing PFAS-related FCAs, continued review and revision of FCA approaches and best practices are vital. Nonetheless, consistent, widely applicable, PFAS-specific approaches informing methods, critical concentration thresholds, and priority compounds may assist practitioners in PFAS-related FCA development and possibly reduce variability between states and jurisdictions. Integr Environ Assess Manag 2024;00:1-20. © 2024 SETAC.

There's Something in What We Eat: An Overview on the Extraction Techniques and Chromatographic Analysis for PFAS Identification in Agri-Food Products

Per- and polyfluorinated alkyl substances (PFASs) are a group of anthropogenic chemicals used in a range of industrial processes and consumer products. Recently, their ubiquitous presence in the environment as well as their toxicological effects in humans have gained relevant attention. Although the occurrence of PFASs is widely investigated in scientific community, the standardization of analytical method for all matrices still remains an important issue. In this review, we discussed extraction and detection methods in depth to evaluate the best procedures of PFAS identification in terms of analytical parameters (e.g., limits of detection (LODs), limits of quantification (LOQs), recoveries). Extraction approaches based on liquid-liquid extraction (LLE), alkaline digestion, and solid phase extraction (SPE), followed by liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) analysis are the main analytical methods applied in the literature. The results showed detectable recoveries of PFOA and PFOS in meat, milk, vegetables, eggs products (90.6-101.2% and of 89.2-98.4%), and fish (96-108%). Furthermore, the low LOD and LOQ values obtained for meat (0.00592-0.01907 ng g-1; 0.050 ng g-1), milk (0.003-0.009 ng g-1; 0.010-0.027 ng g-1), fruit (0.002-0.009 ng g-1; 0.006-0.024 ng g-1), and fish (0.00369-0.017.33 ng g-1; 0.05 ng g-1) also confirmed the effectiveness of the recent quick, easy, cheap, effective, rugged, and safe method (QuEChERS) for simple, speedy, and sensitive ultra-trace PFAS analysis.

Nationwide distribution of perfluoroalkyl ether carboxylic acids in Chinese diets: An emerging concern

With the phase-out of perfluorooctanoic acid (PFOA) and its replacement by perfluoroalkyl ether carboxylic acids (PFECAs), there is a potential for increased exposure to various new PFECAs among the general population in China. While there are existing studies on dietary exposure to legacy perfluoroalkyl and polyfluoroalkyl substances (PFASs), research on dietary exposure to PFECAs, especially among the general Chinese populace, remains scarce. In the present study, we investigated the distribution of PFECAs in dietary sources from 33 cities across five major regions in China, along with the associated dietary intake. Analysis indicated that aquatic animal samples contained higher concentrations of legacy PFASs compared to those from terrestrial animals and plants. In contrast, PFECAs were found in higher concentrations in plant and terrestrial animal samples. Notably, hexafluoropropylene oxide dimer (HFPO-DA) was identified as the dominant compound in vegetables, cereals, pork, and mutton across the five regions, suggesting widespread dietary exposure. PFECAs constituted the majority of PFAS intake (57 %), with the estimated daily intake (EDI) of HFPO-DA ranging from 2.33 to 3.96 ng/kg bw/day, which corresponds to 0.78-1.32 times the reference dose (RfD) (3.0 ng/kg bw/day) set by the United States Environmental Protection Agency. Given the ubiquity of HFPO-DA and many other PFECAs in the nationwide diet of China, there is an urgent need for further research into these chemicals to establish relevant safety benchmarks or consumption advisory values for the diet.

The sources and bioaccumulation of per- and polyfluoroalkyl substances in animal-derived foods and the potential risk of dietary intake

Per- and polyfluoroalkyl substances (PFAS) have attracted increasing attention due to their environmental persistence and potential toxicity. Diet is one of the main routes of human exposure to PFAS, particularly through the consumption of animal-derived foods (e.g., aquatic products, livestock and poultry, and products derived from them). This review summarizes the source, bioaccumulation, and distribution of PFAS in animal-derived foods and key influential factors. In most environmental media, perfluorooctanoic acid and perfluorooctane sulfonate are the dominant PFAS, with the levels of short-chain PFAS such as perfluorobutyric acid and perfluorohexane sulfonate surpassing them in some watersheds and coastal areas. The presence of PFAS in environmental media is mainly influenced by suspended particulate matter, microbial communities as well as temporal and spatial factors, such as season and location. Linear PFAS with long carbon chains (C ≥ 7) and sulfonic groups tend to accumulate in organisms and contribute significantly to the contamination of animal-derived foods. Furthermore, PFAS, due to their protein affinity, are prone to accumulate in the blood and protein-rich tissues such as the liver and kidney. Species differences in PFAS bioaccumulation are determined by diet, variances in protein content in the blood and tissues and species-specific activity of transport proteins. Carnivorous fish usually show higher PFAS accumulation than omnivorous fish. Poultry typically metabolize PFAS more rapidly than mammals. PFAS exposures in the processing of animal-derived foods are also attributable to the migration of PFAS from food contact materials, especially those in higher-fat content foods. The human health risk assessment of PFAS exposure from animal-derived foods suggests that frequent consumption of aquatic products potentially engender greater risks to women and minors than to adult males. The information and perspectives from this review would help to further identify the toxicity and migration mechanism of PFAS in animal-derived foods and provide information for food safety management.

Tracing the Bioaccessibility of Per- and Polyfluoroalkyl Substances in Fish during Cooking Treatment

The effect of cooking on the contents of per- and polyfluoroalkyl substances (PFAS) in foods has been widely studied, but whether cooking-induced structural and chemical modifications in foods affect the oral bioaccessibility of PFAS remains largely unknown. In this study, three kinds of fishes with different fat contents were selected, and the bioaccessibility of PFAS during cooking treatment (steaming and frying) was evaluated using in vitro gastrointestinal simulation with gastric lipase addition. The results showed that related to their molecular structures, the bioaccessibility of an individual PFAS varied greatly, ranging from 26.0 to 108.1%. Cooking can reduce the bioaccessibility of PFAS, and steaming is more effective than oil-frying; one of the possible reasons for this result is that the PFAS is trapped in protein aggregates after heat treatment. Fish lipids and cooking oil ingested with meals exert different effects on the bioaccessibility of PFAS, which may be related to the state of the ingested lipid/oil and the degree of unsaturation of fatty acids. Gastric lipase boosted the release of long-chain PFAS during in vitro digestion, indicating that the degree of lipolysis considerably influences the bioaccessibility of hydrophobic PFAS. Estimated weekly PFAS intakes were recalibrated using bioaccessibility data, enabling more accurate and reliable dietary exposure assessments.

Bioaccumulation and risk mitigation of legacy and novel perfluoroalkyl substances in seafood: Insights from trophic transfer and cooking method

Per- and polyfluoroalkyl substances (PFAS) have widespread application in industrial and civil areas due to their unique physical and chemical properties. With the increasingly stringent regulations of legacy PFAS, various novel alternatives have been developed and applied to meet the market demand. Legacy and novel PFAS pose potential threats to the ecological safety of coastal areas, however, little is known about their accumulation and transfer mechanism, especially after cooking treatment. This study investigated the biomagnification and trophic transfer characteristics of PFAS in seafood from the South China Sea, and assessed their health risks after cooking. Fifteen target PFAS were all detected in the samples, of which perfluorobutanoic acid (PFBA) was dominant with concentrations ranging from 0.76 to 4.12 ng/g ww. Trophic magnification factors (TMFs) > 1 were observed for perfluorooctane sulfonate (PFOS) and 6:2 chlorinated polyfluoroalkyl ether sulfonic acid (F-53B), indicating that these compounds experienced trophic magnification in the food web. The effects of different cooking styles on PFAS occurrence were further explored and the results suggested that ΣPFAS concentrations increased in most organisms after baking, while ΣPFAS amounts decreased basically after boiling and frying. Generally, there is a low health risk of exposure to PFAS when cooked seafood is consumed. This work provided quantitative evidence that cooking methods altered PFAS in seafood. Further, suggestions to mitigate the health risks of consuming PFAS-contaminated seafood were provided.

Prevalence of per- and polyfluoroalkyl substances (PFASs) in marine seafood from the Gulf of Guinea

PFASs are ubiquitous in the global environment due to their wide use, persistence and bioaccumulation, and are of concern for human health. This study investigated the levels of PFASs in seafood with a view to provide knowledge on the occurrence of PFASs in marine resources and to evaluate seafood safety and human health risk via dietary exposure to coastal communities in the Gulf of Guinea, where there is currently very little data. The sum of targeted PFASs was between 91 and 1510 pg g^-l ww (mean 465 ± 313 pg g^-l ww), with PFOS and long-chain PFCAs prevailing. The concentrations of PFASs in the three species of croakers were species- and location-dependent, with habitat and anthropogenic pressure as likely drivers of the differences. Significantly higher contamination levels were found in male croakers. The trophic transfer and biomagnification of PFASs from shrimps to croakers was evidenced for PFOS and long-chain PFCAs (with a significant increase of contaminants from the prey to the predator). The calculated estimated daily intakes (EDIs) and hazard ratio (HR) for PFOS in croakers (whole fish and muscles) and shrimp were lower than the European Food and Safety Agency's recommended level for PFOS (1.8 ng kg^-1 day^-1) and below the HR safety threshold value of 1. From the results, based on present safety limits, PFOS levels in croakers and shrimps from the Gulf of Guinea do not pose immediate health risks to the human population. This study provides the first insight regarding the distribution of PFASs in seafood from the tropical NE Atlantic region of the Gulf of Guinea and highlights the need for further monitoring across the Gulf.

Perfluoroalkyl substances in Baltic fish - the risk to consumers

Perfluoroalkyl substances (PFASs) were investigated in five Baltic fish species (sprat, herring, salmon, trout, and cod). Each species' median lower bound (LB) concentration of ∑14 PFASs was as follows: in sprat it was 3.54 µg/kg wet weight (w.w.), in cod 2.15 µg/kg w.w., in salmon 2.10 µg/kg w.w., in trout 2.03 µg/kg w.w. and in herring 1.74 µg/kg w.w.. Regarding the species' median LB of ∑4 PFASs (perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorohexane sulfonic acid (PFHxS)), sprat was the most contaminated with 2.90 µg/kg w.w. and herring was the least with 1.17 µg/kg w.w.. Among all PFASs, PFOS was found in the highest concentrations (range 0.04-9.16 µg/kg w.w.) and the percentage share in the total concentration of ∑14 PFASs was between 56 and 73%. The average proportion of linear PFOS (L-PFOS) in the total PFOS (branched and linear) was the highest in salmon at 89% and trout at 87%, and in the other three species it ranged from 75 to 80%. Different consumption scenarios were assumed and the intake of PFASs was calculated for children and adults. Dietary intake via fish consumption was 3.20-25.13 ng/kg of body weight (b.w.) for children and 1.68-8.30 ng/kg b.w. for adults. Baltic fish caught along Polish coastal areas are a significant source of PFASs, especially for children.

Cooking methods effectively alter perfluoroalkyl substances and nutrients in cultured and wild bullfrogs

The ubiquitous distribution of perfluoroalkyl substances (PFASs) poses a threat to the health of aquatic organisms and humans. Bullfrogs are considered a popular aquatic food product in South China, providing high protein and tasty cuisine; however bullfrogs have been shown to contain significant concentrations of PFASs. However, the risk-benefit ratios of PFASs and nutrient contents in cooked bullfrogs are not well understood. PFASs and nutrients were investigated in raw and cooked specimens of cultured and wild bullfrogs in this study. Novel PFASs showed higher detection levels and accumulation in wild bullfrogs than in cultured bullfrogs. Potential factors such as fat and fatty acid ratio affected PFASs accumulation in different tissues and by different cooking methods of bullfrogs. All cooking methods can reduce PFASs in edible tissues while significantly enhancing the nutritive value index (NVI) compared to raw bullfrogs. Steaming was the most effective way to reduce PFASs (rate of reduction was over 66%) and resulted in a lower risk of contributing to arteriosclerosis than other cooking methods assessed by atherogenicity index (AI) values. Cultured bullfrogs instead of wild bullfrogs were recommended for human consumption, and steaming was regarded as a better cooking method in terms of risk-benefit concerns. Overall, this work provides quantitative analysis of cooking methods that alter PFASs and nutrients in bullfrogs.

Transport and transformation of perfluoroalkyl acids, isomer profiles, novel alternatives and unknown precursors from factories to dinner plates in China: New insights into crop bioaccumulation prediction and risk assessment

Perfluoroalkyl acids (PFAAs) are contaminants of global concern, and the inadvertent consumption of PFAA-contaminated crops may pose a threat to public health. Therefore, systematically studying their source tracing, bioaccumulation prediction and risk assessments in crops is an urgent priority. This study investigated the source apportionment and transport of PFAAs and novel fluorinated alternatives (collectively as per- and polyfluoroalkyl substances, PFASs) from factories to agricultural fields in a fluorochemical industrial region of China. Furthermore, bioaccumulation specificities and prediction of these chemicals in different vegetables were explored, followed by a comprehensive risk assessment from agricultural fields to dinner plates which considered precursor degradation. A positive matrix factorization model revealed that approximately 70 % of PFASs in agricultural soils were derived from fluorochemical manufacturing and metal processing. Alarming levels of ∑PFASs ranged 8.28-84.3 ng/g in soils and 163-7176 ng/g in vegetables. PFAS with short carbon chain or carboxylic acid group as well as branched isomers exhibited higher environmental transport potentials and bioaccumulation factors (BAFs) across a range of vegetables. The BAFs of different isomers of perfluorooctanoic acid (PFOA) decreased as the perfluoromethyl group moved further from the acid functional group. Hexafluoropropylene oxide dimer acid (GenX) showed relatively low BAFs, probably related to its ether bond with a high affinity to soil. Vegetables with fewer Casparian strips (e.g., carrot and radish), or more protein, possessed larger BAFs of PFASs. A bioaccumulation equation integrating critical parameters of PFASs, vegetables and soils, was built and corroborated with a good contamination prediction. After a total oxidizable precursors (TOP) assay, incremental perfluoroalkyl carboxylic acids (PFCAs) were massively found (325-5940 ng/g) in edible vegetable parts. Besides, precursor degradation and volatilization loss of PFASs was firstly confirmed during vegetable cooking. A risk assessment based on the TOP assay was developed to assist the protection of vegetable consumers.

Perfluoroalkyl acids in representative edible aquatic species from the lower Yangtze River: Occurrence, distribution, sources, and health risk

Perfluoroalkyl acid (PFAA) exposure poses a potential hazard to wildlife and humans. Food consumption is one of the main routes of PFAA exposure for the general population, with aquatic organisms being the major contributors. To evaluate the risk of coastal residents' intake of wild aquatic organisms, 14 PFAAs were detected in crucian carp and oriental river prawn from 18 sampling sites from the lower reaches of Yangtze River. The total PFAA (∑PFAA) concentrations ranged from 5.9 to 51.3 ng/g wet weight (ww) in the muscle of crucian carp and river prawn, suggesting the potential risk to human and wildlife. Perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and long-chain PFAAs (C ≥ 10) were the main pollutants in the tissues of crucian carp and river prawn, which are known for their higher bioaccumulation capacity. The ∑PFAA concentration in all the samples showed an increasing trend from upstream to downstream and was higher in the south bank, owing to population density, prevailing winds, background pollution and industrial emission. Principal component analysis-multiple linear regression and Pearson correlation analysis showed that WWTP effluent, industrial pollution and surface runoff ware the main sources of PFAAs in the aquatic organisms and industrial pollution highest contributor, suggesting better regulation is needed to manage them. The assessment of risk to human health and wild life suggested a low risk for most residents of cities along the Yangtze River except for resident of Nantong, where frequent consumption of wild aquatic organisms may cause potential risk to human health, especially for traditional eaters and middle-aged people.

Thermal processing reduces PFAS concentrations in blue food - A systematic review and meta-analysis

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment and often ingested with food. PFAS exposure in people can have detrimental health consequences. Therefore, reducing PFAS burdens in food items is of great importance to public health. Here, we investigated whether cooking reduces PFAS concentrations in animal-derived food products by synthesizing experimental studies. Further, we examined the moderating effects of the following five variables: cooking time, liquid/animal tissue ratio, cooking temperature, carbon chain length of PFAS and the cooking category (oil-based, water-based & no-liquid cooking). In our systematic review searches, we obtained 512 effect sizes (relative differences in PFAS concentration between raw and cooked samples) from 10 relevant studies. These studies exclusively explored changes in PFAS concentrations in cooked seafood and freshwater fish. Our multilevel-meta-analysis has revealed that, on average, cooking reduced PFAS concentrations by 29%, although heterogeneity among effect sizes was very high (I² = 94.65%). Our five moderators cumulatively explained 49% of the observed heterogeneity. Specifically, an increase in cooking time and liquid/animal tissue ratio, as well as shorter carbon chain length of PFAS (when cooked with oil) were associated with significant reductions in PFAS concentrations. The effects of different ways of cooking depended on the other moderators, while the effect of cooking temperature itself was not significant. Overall, cooking can reduce PFAS concentrations in blue food (seafood and freshwater fish). However, it is important to note that complete PFAS elimination requires unrealistically long cooking times and large liquid/animal tissue ratios. Currently, literature on the impact of cooking of terrestrial animal produce on PFAS concentrations is lacking, which limits the inference and generalisation of our meta-analysis. However, our work represents the first step towards developing guidelines to reduce PFAS in food via cooking exclusively with common kitchen items and techniques.

Quantifying Indirect Contribution from Precursors to Human Body Burden of Legacy PFASs Based on Paired Blood and One-Week Duplicate Diet

The restriction on legacy perfluoroalkyl substances (PFASs) has led to increasing application and contamination of their precursors and novel alternatives. However, the indirect contribution from precursors has not been well characterized. In this study, 24 PFASs were measured in the paired human blood and urine from general volunteers (n = 20), as well as their corresponding exposure matrices (7 day duplicate diet, drinking water and dust). Perfluorooctanoic acid (PFOA) was predominant, followed by 6:2 chlorinated polyfluoroalkyl ether sulfonate (6:2 Cl-PFESA), contributing 21.6-47.0 and 6.6-20.0% of the total concentrations, respectively. Total oxidable precursor (TOP) assay and isomeric analysis coupled with a toxicokinetic model suggested that around 19% of perfluorooctane sulfonate (PFOS) in human was contributed by its precursors. The strong correlation between the estimated daily intake (EDI) and human blood concentration for 6:2 Cl-PFESA suggested that it was mainly contributed by direct exposure. The bioavailability of 6:2 Cl-PFESA in the food matrices was estimated as 18.6% by comparing the estimated and measured blood concentrations, implying that human exposure might be overestimated if the bioavailability of PFASs in food was not considered. Assuming that they had a similar bioavailability, it was estimated that ca. 20% of PFOS body burden was from indirect exposure to its precursors, which was supported by TOP assay.

PFASs intake from fish, eggs and drinking water in Greece in relation to the safety limits for weekly intake proposed in the EFSA scientific opinion of 2020

Food consumption has been recognized as the most significant contributor to human exposure to polyfluoroalkyl and perfluoroalkyl substances (PFASs) for the general population. In 2020, EFSA introduced for the first time safety limit of 4.4 ng/kg body weight (bw) for weekly intake for the sum of perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) which are all perfluoralkyl acids (PFAAs) that belong to PFASs group. Fish and eggs have been found to contribute significantly, almost 50 % to PFOS and PFOA dietary intake of the Greek population. In the present study, estimation of human intake of these four PFASs from fish, eggs and drinking water consumption is attempted. Data from EFSA food consumption database for fish and eggs are used for assessment. Mean weekly intake estimated is above the tolerable weekly intake (TWI) recently proposed, mainly due to fish consumption. Exceedance of the proposed TWI emphasizes the need for continuous monitoring of levels of PFASs in food in parallel with efforts to lower these levels.

Postflood Monitoring in a Subtropical Estuary and Benchmarking with PFASs Allows Measurement of Chemical Persistence on the Scale of Months

Measurements of chemical persistence in natural environments can provide insight into behavior not easily replicated in laboratory studies. However, it is difficult to find environmental situations suitable for such measurements, particularly for substances with half-lives exceeding several weeks. The objective of this study was to demonstrate that a strategic postflood monitoring campaign can be used to quantify transformation half-lives on the scale of months in a real aquatic system. Water samples were collected in the upper Brisbane River estuary on 36 occasions over 37 weeks and analyzed for 127 pharmaceuticals and personal care products (PPCPs), pesticides, and perfluoroalkyl substances (PFASs). High quality time trend data were obtained for 41 substances. For many of these, data on the input of a wastewater treatment plant to the upper estuary were also obtained. A mass balance model of the estuary stretch was formulated and parametrized using PFASs as persistent benchmarking chemicals. Transformation half-life estimates were obtained for 10 PPCPs and 7 pesticides ranging from 18 to 260 days. Furthermore, insight was obtained into dominant transformation processes as well as the magnitude of chemical inputs to the estuary and their sources. The approach developed shows that under certain conditions, estuaries can be used to quantify the persistence of organic contaminants with half-lives of the order of several months.

Migration histories and perfluoroalkyl acid (PFAA) loads in an estuarine fish: A novel union of analyses to understand variation in contaminant concentrations

Previous studies have shown that accumulation of perfluoroalkyl acids (PFAAs) in the tissues of aquatic species is highly variable. Movement and migration patterns in these species represent an important consideration when evaluating contaminant accumulation in exposed biota, and may have a large influence on the risk profiles for migratory seafood species. In this study, relationships between PFAA concentrations in muscle and liver tissue, and recent fish migration history (inferred from metals profiles in fish otoliths, otherwise known as otolith chemistry) were evaluated in Sea Mullet (Mugil cephalus). A greater number of PFAAs, and higher concentrations, were found in liver compared to muscle tissue. Perfluorooctane sulfonate (PFOS) was present in highest concentrations in both muscle and liver tissues, and there was strong correlation in concentrations between these two tissues. PFOS was found to decrease and increase alongside recent strontium and barium concentrations (respectively) in the otolith, suggesting higher concentrations of PFAAs in fish recently exposed to comparatively lower salinity environments. This study highlights how otolith chemistry can be employed to examine links between contaminant concentrations in fish, and their recent migration history. This approach shows promise for studying contaminant residues in mobile seafood species within the natural environment.

Trial of a novel experimental design to test depuration of PFASs from the edible tissues of Giant Mud Crab following exposure under natural conditions in the wild

Poly and perfluorinated alkyl substances (PFASs) are persistent organic pollutants (POPs) that are highly resistant to environmental degradation, and have been detected in a broad range of terrestrial and aquatic species. Portunid crabs have been shown to accumulate comparatively high concentrations of PFASs, but previous work examining depuration in crabs was inconclusive. Here, we trialled a novel experimental design to study depuration of PFASs from edible tissues of portunid crabs, using paired claw samples, and trial this design with Giant Mud Crab Scylla serrata exposed to the contaminant under natural conditions. We found evidence for depuration of perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS) and perfluorooctanoic acid (PFOA), but with depuration half-lives as high as 40 days (for PFOS). We also observed substantial variability in the data, including differences in PFAS concentrations between claws from the same individuals, potentially resulting from claw loss and re-growth prior to capture. These results have broad implications for assessing and minimising exposure risk in seafood species.

Animal size impacts perfluoroalkyl acid (PFAA) concentrations in muscle tissue of estuarine fish and invertebrate species

Environmental emissions of perfluoroalkyl acids (PFAAs) often contaminate aquatic ecosystems and accumulate in the species therein. This can represent an exposure pathway for human populations where seafood is consumed. Concentrations of PFAAs in water breathing animals may be a function of many different factors, however, little is known about how these different factors impact contaminant accumulation in estuarine and marine species. This study explores the relationships between PFAA accumulation and two key variables, animal size and sediment concentrations, for a number of important seafood species. Sixty Dusky Flathead (Platycephalus fuscus), 58 Mulloway (Argyrosomus japonicus) and 53 Giant Mud Crab (Scylla serrata) were tested for perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS) in edible tissues, and the concentrations compared with animal size and sediment concentrations at the location of capture. PFAAs showed a high degree of variation among species, and PFOA and PFHxS were only common in Giant Mud Crab. Log-transformed PFOS concentrations in all three species showed negative correlations with animal size (weight). There was limited evidence for relationships between PFOS muscle tissue concentration and sediment PFOS concentration. The patterns observed are potentially explained by changes in trophic position, relative growth rate, consumption rate and metabolic rate, throughout the species life history. The results contrast with observations for other persistent organic pollutants, whereby larger individuals tend to carry greater contaminant loads. Future work is required to establish whether these patterns are evident for PFAAs in other species and contaminant sources.

Cooking methods affect the intake of per- and polyfluoroalkyl substances (PFASs) from grass carp

Consumption of fish is one of the predominant sources of human exposure to per- and polyfluoroalkyl substances (PFASs). In this study, the effect of various cooking methods (boiling, steaming, grilling and frying) on the levels of PFASs in fish muscle and the intake of PFASs was explored by using grass carp collected from Tangxun Lake, Wuhan, China. Perfluorooctane sulfonate (PFOS) was the predominant PFASs in raw fish fillets, with the concentrations ranging from 59.6 to 136 ng/g ww, followed by perfluorobutane sulfonate (PFBS) (7.73-51.9 ng/g ww). The concentrations of long-chain PFASs in fish increased after cooking, while those of short-chain PFASs decreased. The amounts of PFASs in the cooked fish fillets decreased except PFOS. Short-chain PFASs, including PFBS and perfluoroheptanoic acid (PFHpA), were dominant in cooking juice. The highest amounts of PFBS in the juices were observed after boiling and frying, even higher than those in cooked fish fillets, suggesting that the release of short-chain PFASs to the cooking juices could not be neglected. Based on these results, the intake of short-chain PFASs amount through cooked fish fillets slightly decreased, but the intake of PFOS amount increased. However, consumption of cooking juice (fish soup) could increase the exposure risk of PFBS. Comprehensively considering the increase of PFOS and decrease of total PFASs, boiling may be the relatively better method to cook fish. As PFASs are ubiquitous and inevitable in aquatic food, it is thus important to choose appropriate cooking processes and dietary habits for reducing the intake of different PFASs from fish.

Environmental levels and human body burdens of per- and poly-fluoroalkyl substances in Africa: A critical review

Per- and polyfluoroalkyl substances (PFASs) are known organic pollutants with adverse health effects on humans and the ecosystem. This paper synthesises literature about the status of the pollutants and their precursors, identifies knowledge gaps and discusses future perspectives on the study of PFASs in Africa. Limited data on PFASs prevalence in Africa is available because there is limited capacity to monitor PFASs in African laboratories. The levels of PFASs in Africa are higher in samples from urban and industrialized areas compared to rural areas. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are the dominant PFASs in human samples from Africa. Levels of PFOS and PFOA in these samples are lower than or comparable to those from industrialized countries. PFOA and PFOS levels in drinking water in Africa are, in some cases, higher than the EPA drinking water guidelines suggesting potential risk to humans. The levels of PFASs in birds' eggs from South Africa are higher, while those in other environmental media from Africa are lower or comparable to those from industrialized countries. Diet influences the pollutant levels in fish, while size and sex affect their accumulation in crocodiles. No bioaccumulation of PFASs in aquatic systems in Africa could be confirmed due to small sample sizes. Reported sources of PFASs in Africa include municipal landfills, inefficient wastewater treatment plants, consumer products containing PFASs, industrial wastewater and urban runoff. Relevant stakeholders need to take serious action to identify and deal with the salient sources of PFASs on the African continent.

Managing health risks of perfluoroalkyl acids in aquatic food from a river-estuary-sea environment affected by fluorochemical industry

Substantial perfluoroalkyl acids (PFAAs) production still occurs in China, and the consumption of aquatic products is a critical exposure pathway of PFAAs in humans. In this study, specimens of 16 freshwater and 40 marine species were collected in the river-estuary-sea environment affected by a mega fluorochemical industry park in China in 2015, and the edible tissues of these organisms were analyzed for PFAA levels. Perfluorooctanoic acid (PFOA) was the dominating contaminant with an overall contribution of more than 90%, and concentrations as high as 2161 ng/g wet weight (measured in the freshwater winkle). All species with the greatest PFOA levels were benthic. The trophic magnification factor (TMF) of PFOA was 1.10 for freshwater species and 1.28 for marine species, indicating that PFOA was slightly magnifying. Analysis of carbon source indicated that freshwater species were more benthic feeding, while marine species were more pelagic feeding. Aquatic food consumption screening values of PFOA were modified according to estimated daily intake (EDI) values, which generated recommendations for limited meal categories and the do-not-eat category. Thus, this study provides recommendations for mitigating the health risks of PFAA-contaminated aquatic food, ranging from food selection to consumption frequency and proper food processing.

Metabolomic profiles associated with exposure to per- and polyfluoroalkyl substances (PFASs) in aquatic environments

Per- and polyfluoroalkyl substances (PFASs) are frequently detected in aquatic environments. Longer chained perfluoroalkyl acids (PFAAs), in particular, have been found to bioaccumulate in a broad range of aquatic biota. PFAAs have a physiochemical similarity to naturally occurring fatty acids and could potentially disrupt metabolic processes, however, there has been limited study in this area, especially in aquatic species. In this study, the associations between PFAAs and metabolite profiles were investigated in crustaceans. Eastern School Prawn (Metapenaeus macleayi) were obtained from three different locations (n = 15 per location) with similar environmental conditions but different levels of PFAA contamination. The concentrations of PFAAs, fatty acids and amino acids were analysed and differences in PFAA and metabolite profiles were evaluated. Different PFAA profiles were mirrored by significant differences in the composition of both fatty acid and amino acid profiles, indicating a potential association between PFAA concentration and the composition of metabolites in prawns. These results highlight a need for further research investigating the impacts of PFAA exposure, with the current study providing a foundation for further investigation of the relationship between PFAA bioaccumulation and organism metabolism.