Bioaccumulation characteristics of perfluoroalkyl acids (PFAAs) in coastal organisms from the west coast of South Korea

Long-term trends of persistent toxic substances and potential toxicities in sediments along the west coast of South Korea

For decades, in response to industrialization and urbanization, environmental qualities of estuarine and coastal areas of the west coast of Korea have been deteriorating. Long-term changes in concentrations of persistent toxic substances (PTSs) in sediments, including PAHs, styrene oligomers, nonylphenols, and metals and their potential toxicities via AhR- and ER-mediated potencies, and bioluminescent bacterial inhibition, were investigated. Long-term monitoring in five estuarine and coastal areas (2010-2018; 10 sites) showed that concentrations of PAHs and nonylphenols in sediments have declined while concentrations of some metals, Cd, Cr, and Hg have increased. Similarly, AhR-mediated potencies in sediments have declined, but inhibitions of bioluminescent bacteria have increased. Concentrations of sedimentary PAHs and AhR-mediated potencies were significantly (p < 0.01) and positively correlated. Sources of PAHs from combustion have been gradually declining while inputs from vehicle exhaust by-products have been increasing. Overall, this study brought our attention a balanced regulation in chemical-specific manner.

Distribution, sources and human risk of perfluoroalkyl acids (PFAAs) in a receiving riverine environment of the Nanjing urban area, East China

In recent years, perfluoroalkyl acids (PFAAs) have become ubiquitously distributed in water environments, especially in riverine waters receiving effluents from wastewater treatment plants (WWTPs) in urban areas. With rapid economic development, China has become the main market of manufacturing and consuming fluorinated products. While studies concerning PFAAs on dimension of urban water system are scarce. To elucidate the distribution patterns of PFAAs using multi-matrices, the effects of spatial-temporal factors on the partition behaviors of PFAAs were investigated in different riverine environments in the downtown area of Nanjing, East China. Predominated by perfluorooctanoic acid (PFOA), sum PFAAs (∑PFAAs) in the water phase were with concentrations of 0.8˜274.6 ng/L, characteristically higher in the dry season and lower in the wet season. The composition profiles in sediments (∑PFAAs 0.8˜11.4 ng/g dry weight) differed from that in water, being with a larger proportion of longer-chain PFAAs. The main sources of PFAAs in water were identified as industrial discharge, uncontrolled sewage discharge or WWTP effluents, surface runoff and nonpoint sources. The discharge fluxes of ∑PFAAs from Nanjing City can reach at 916.5 g/d for the Qinhuai River and 134.1 g/d for WWTPs along the Yangtze River. Fish have been shown to accumulate PFAAs in various tissues, with bioaccumulation positively correlated with perfluoroalkyl chain length. The hazard indexes associated with consumption of river fish were estimated low for Nanjing local population.

Comparisons of tissue distributions and health risks of perfluoroalkyl acids (PFAAs) in two fish species with different trophic levels from Lake Chaohu, China

Perfluoroalkyl acids (PFAAs) are a type of persistent organic pollutants that are widely distributed in multiple environmental media and organisms and have a teratogenic effect on and toxicity to animals and humans. The residual levels of seventeen PFAAs in the tissues of two regular consumption fish species, Culter erythropterus and Aristichthys nobilis in Lake Chaohu were measured by a high-performance liquid chromatograph - mass spectrometer (HPLC-MS). The distributions of PFAAs and the effect of the lipid contents were analyzed, and the health risks of typical PFAAs were evaluated. The results showed that perfluorohexanoic acid (PFHxA) was the predominant contaminant (80.50 ± 58.31 ng/g and 19.17 ± 12.57 ng/g wet weight, ww), followed by perfluorooctanesulfonic acid (PFOS) (55.02 ± 34.82 and 14.79 ± 6.24 ng/g, ww) in both fish. The level of total PFAAs was the highest in the liver tissues of Culter erythropterus (359.87 ng/g, ww) and the lowest in the kidney tissues in A. nobilis (10.06 ng/g, ww). Due to the higher trophic level of C. erythropteru, the total PFAA concentrations were significantly higher in all tissues than those in A. nobilis. Liver muscle ratio of C. erythropteru was the highest, indicating the most accumulation in the liver. The concentrations of PFAAs in fish tissues were influenced by the lipid content, resulting in a difference between the lipid-normalized concentrations and the wet weight concentrations of the PFAAs. The non-carcinogenic risks of PFOS were higher than those of PFOA through the ingestion of C. erythropterus and A. nobilis. Both the carcinogenic and non-carcinogenic risks of C. erythropterus were greater than those of A. nobilis, and fish tissue intake could cause an increasing of risks up to 60%, indicating that long-term and large amount ingestion of carnivorous fish and related tissues with higher trophic level, such as C. erythropterus should be avoided.

Per- and polyfluoroalkyl substances in commercially available biosolid-based products: The effect of treatment processes

Per- and polyfluoroalkyl substances (PFAS) have been used in a variety of consumer and industrial products and are known to accumulate in sewage sludge due to sorption and their recalcitrant nature. Treatment processes ensure safe and high-quality biosolids by reducing the potential for adverse environmental impacts such as pathogen levels; however, they have yet to be evaluated for their impact on the fate of PFAS. The objective of this study was to compare PFAS concentrations in four commercially available biosolid-based products that received different types of treatments: heat treatment, composting, blending, and thermal hydrolysis. Seventeen perfluoroalkyl acids (PFAAs) were quantified using liquid chromatography with tandem quadrupole time-of-flight mass spectrometry followed by screening for 30 PFAA precursors. Treatment processes did not reduce PFAA loads except for blending, which served only to dilute concentrations. Several PFAA precursors were identified with 6:2 and 8:2 fluorotelomer phosphate diesters in all samples pre- and post-treatment. PRACTITIONER POINTS: Heat treatment and composting increased perfluoroalkyl acid (PFAA) concentrations. Only dilution from blending with non-PFAS material decreased PFAA concentrations. Thermal hydrolysis process had no apparent effect on PFAA concentrations. PFAS sources are a greater driver of PFAS loads in biosolid-based products than treatment processes.

Factors affecting spatial and temporal patterns in perfluoroalkyl acid (PFAA) concentrations in migratory aquatic species: a case study of an exploited crustacean

Per- and poly-fluorinated alkyl substances (PFASs, including perfluoroakyl acids [PFAAs]) have been used in a range of applications, and are widely distributed throughout the environment including environmental media in aquatic systems. Recent literature provides multiple reports of these compounds in a range of aquatic species, but temporal and spatial variability in tissue concentrations is rarely assessed in a rigorous way. Using an important fishery species of representative biology as a case study (Eastern School Prawn, Metapenaeus macleayi), temporal (month-to-month, and year-to-year) and spatial (intra-estuarine and oceanic) variability in PFAAs concentrations was assessed alongside potential contributing factors. Perfluorooctane sulfonate (PFOS) was the dominant PFAA detected, and there was significant spatial variation in concentration driven primarily by distance to major point sources. There was also substantial variation in PFOS among months, likely driven by behavioural physiological or ecological factors. Importantly, muscle tissue concentrations were unrelated to surface water inputs of PFAAs into the estuary. A numerical model linking prawn migration data with concentrations in the estuarine nursery accurately predicted PFOS concentrations in adjacent oceanic trawling grounds. The results demonstrate the magnitude of temporal and spatial variation in PFAA concentrations, which has implications for assessing PFAA exposure risk through seafood consumption for free-ranging aquatic animals.

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

A one-year monitoring study was conducted in a macrotidal estuary to assess the temporal variations and partitioning behavior of perfluoroalkyl and polyfluoroalkyl substances (PFASs). Surface water, suspended particulate matter (SPM), and invertebrates including zooplankton (copepods, mysids) and shrimps were sampled on a monthly basis in the Gironde Estuary (SW France). Environmental parameters such as suspended solid loads, salinity, and river water flow rate were highly variable at the study site. However, moderate seasonal variations were observed in terms of PFAS levels and profiles. Summed PFAS (Σ₂₂PFASs) concentrations averaged 6.5 ± 2.7 ng L^-1 in the dissolved phase and 3.0 ± 1.2 ng g^-1 dry weight in the SPM. The Σ₂₂PFASs was in the range of 1.7-13 ng g^-1 wet weight in invertebrates. C₅-C₈ perfluoroalkyl carboxylates (PFCAs) generally prevailed in the dissolved phase, while perfluorooctane sulfonate (PFOS) was dominant in the SPM and biota. Suspended sediment-water partitioning coefficients Log K_D and Log K_OC were correlated with the perfluoroalkyl chain length, as were the particle-bound fraction and bioaccumulation factors (Log BAF). Compound-specific Log BAFs varied within a limited range over the period surveyed. Biomagnification factors (mysids/copepods) were consistently >1 for PFOS, perfluorooctane sulfonamide, and long-chain PFCAs (perfluorodecanoate and perfluorododecanoate), suggesting biomagnification at the base of the estuarine food web.

Perfluoroalkyl substances (PFASs) in the marine environment: Spatial distribution and temporal profile shifts in shellfish from French coasts

Perfluoroalkyl substances (PFASs) were investigated in filter-feeding shellfish collected from 2013 to 2017 along the English Channel, Atlantic and Mediterranean coasts of France. PFOS (perfluorooctane sulfonate), PFTrDA (perfluorotridecanoic acid), PFTeDA (perfluorotetradecanoic acid), PFDoDA (perfluorododecanoic acid) and PFUnDA (perfluoroundecanoic acid) were detected in more than 80% of samples, thus indicating widespread contamination of the French coastal environment by these chemicals. The distribution of PFAS concentrations showed differences according to sampling locations and years. PFOS was the predominant PFAS in most samples collected from English Channel and Atlantic coasts until 2014, but the opposite was observed in 2015, 2016 and 2017, while perfluoroalkyl carboxylic acids (PFCAs) prevailed in Mediterranean samples in all study years. Among PFCAs, PFTrDA showed the highest maximum (1.36 ng g^-1 ww) and median (0.077 ng g^-1 ww) concentrations in 2016-2017. Other PFAS median concentrations were within the 0.014 (PFNA) - 0.055 (PFTeDA) ng g^-1 ww range. The profiles determined each year in most Mediterranean samples suggest distinctive sources. PFOS median concentrations showed a significant decrease over the study years, from 0.118 to 0.126 ng g^-1 ww in 2013-2015 to 0.066 ng g^-1 ww in 2016 and 2017. ∑PFCAs showed no trends in concentration ranges over the same years. The shift in PFAS profiles from PFOS to long-chain PFCAs over the study period reflects PFOS production phase-out, combined with continuous inputs of PFCAs into the marine environment. These results provide reference data for future studies of the occurrence of contaminants of emerging concern on European coasts.

Occurrence and bioaccumulation of persistent toxic substances in sediments and biota from intertidal zone of Abu Ali Island, Arabian Gulf

North Abu Ali Island is contaminated by crude oil from exogenous sources with a variety of persistent toxic substances (PTSs) being input into intertidal sediments. We detected an array of PTSs in sediments and benthic biota off north Abu Ali Island (Arabian Gulf), including 35 polycyclic aromatic hydrocarbons (PAHs), 6 alkylphenols (APEOs), 10 styrene oligomers (SOs), and tributyltin. The PTS concentrations were generally greater than those reported in other areas of Arabian Gulf. PAHs mainly originated from petrogenic sources, and APEOs and SOs seem to be of recent origin. Field-based biota-sediment accumulation factors (BSAF) varied by taxa and compounds, but clearly depended on the log K_ow values of individual compounds. Some PTSs exceeded the established guidelines for sediments and biota; we found particularly great BSAFs for alkyl-naphthalenes (C1- and C2-), nonylphenol monoethoxylates, and 2,4,6-triphenyl-1-hexene. Remediation will require on-site clean-up of toxic chemicals together with immediate efforts on preventing input of current pollution sources in the given area.

Occurrence and health risk of perfluoroalkyl acids (PFAAs) in seafood from Yellow Sea, China

PFAAs have emerged as persistent organic pollutants (POPs) in a variety of environmental matrixes and biota, posing potential hazards for wildlife and humans. Diet has been considered as an important source for human exposure to PFAAs and seafood accounts for a relatively large proportion in human diets, especially for coastal residents. In an effort to clarify the impact of PFAAs in seafood on human health, 17 PFAAs were determined in 42 pooled seafood samples (14 species) from the Yellow Sea areas, China. The concentrations of total PFAAs (sum of 17 PFAAs, ∑PFAAs) were in the range of 1.10-1067 ng/g dry weight (dw), with the highest concentration found in swimming crab (Portunus trituberculatus) and the lowest in silvery pomfret (Pampus argenteus). Concentrations and composition profiles of PFAAs varied significantly among different species, suggesting that bioaccumulation potential of PFAAs differed from species to species. The distinct spatial distribution of PFAAs in four categories of seafood could be mainly attributed to the contamination patterns of PFAAs in three nearby cities. PFBA was presented as the most abundant PFAA in this study, which was different from the findings in many other studies where PFOS was the predominant compound. Furthermore, the human health risk assessment suggested that a comprehensive action plan is needed to protect people from high exposure to PFAAs through seafood consumption.

Perfluorooctanoic acid (PFOA) and perfluooctane sulfonate (PFOS) induce different modes of action in reproduction to Japanese medaka (Oryzias latipes)

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have widely and frequently used in many industrial sectors, and thus have been frequently found in the environment. These chemicals may act as endocrine disrupting chemicals (EDCs), although the molecular mechanisms are still debated. In this study, Japanese medaka (Oryzias latipes) were exposed to 10 mg/l PFOA and 1 mg/l PFOS for 21 days, and the reproductive responses, such as the fecundity, secondary sexual characteristics and transcriptional levels of vitellogenin (vtg1 and vtg2) and choriogenin (chgh, chghm and chgl), were time-dependently evaluated (day 7, 14 and 21). PFOA and PFOS significantly reduced fecundity, and caused expression changes in the genes with time, although the patterns were different for each chemical and each sex. Different transcriptional regulations of vitellogenin and choriogenin in male suggest that PFOA and PFOS have different mode of actions in reproductive effects despite their similar chemical structure.

Uptake of hydrophobic organic compounds, including organochlorine pesticides, polybrominated diphenyl ethers, and perfluoroalkyl acids in fish and blue crabs of the lower Passaic River, New Jersey, USA

The bioavailability and bioaccumulation of sedimentary hydrophobic organic compounds (HOCs) is of concern at contaminated sites. Passive samplers have emerged as a promising tool to measure the bioavailability of sedimentary HOCs and possibly to estimate their bioaccumulation. We thus analyzed HOCs including organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) in sediment, porewater, and river water using low-density polyethylene passive samplers and in 11 different finfish species and blue crab from the lower Passaic River. In addition, perfluorinated alkyl acids (PFAAs) were measured in grab water samples, sediment, and fish. Best predictors of bioaccumulation in biota were either porewater concentrations (for PCBs and OCPs) or sediment organic carbon (PBDEs and PFAAs), including black carbon (OCPs, PCBs, and some PCDD/F congeners)-normalized concentrations. Measured lipid-based concentrations of the majority of HOCs exceeded the chemicals' activities in porewater by at least 2-fold, suggesting dietary uptake. Trophic magnification factors were >1 for moderately hydrophobic analytes (log octanol-water partitioning coefficient [K_OW ] = 6.5-8.2) with low metabolic transformation rates (<0.01 d^-1 ), including longer alkyl chain PFAAs. For analytes with lower (4.5-6.5) and higher (>8.2) K_OW s, metabolic transformation was more important in reducing trophic magnification. Environ Toxicol Chem 2019;38:872-882. © 2019 SETAC.

Survey design for quantifying perfluoroalkyl acid concentrations in fish, prawns and crabs to assess human health risks

Per and polyfluoroalkyl substances (PFASs) are emerging contaminants that have potential implications for human health. Perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS) are perfluoroalkyl acids (PFAAs) that commonly bioaccumulate in aquatic species exposed to PFAS contaminant sources. Sampling programs aimed at measuring PFAA concentrations in free ranging aquatic animals to assess human health risk are not yet supported by any quantitative analyses to refine sampling effort required to provide a reasonable estimate of summary statistics for a species in a particular area. Here, an extensive, multi-species PFOS and PFHxS data set measured in free-ranging fish and crustaceans is employed to examine the effect of sample size on summary statistics estimated from sample data which are commonly employed in dietary exposure assessments. A unifying, cross-species model suggested that sample sizes between 20 and 40 individuals per species per location should provide a reasonable estimate of mean PFOS concentrations in free-ranging fish or crustaceans, but slightly larger sample sizes (30-50 individuals) may be required if sample medians are to be used in dietary exposure assessments. PFHxS concentrations were highly variable, so larger sample sizes should also be considered if this contaminant is of interest. The results are discussed in light of the levels of sampling effort reported in recent manuscripts, and other important considerations for designing sampling programs.

Bioaccumulation of perfluoroalkyl substances in marine echinoderms: Results of laboratory-scale experiments with Holothuria tubulosa Gmelin, 1791

Bioaccumulation of six perfluoroalkyl substances (PFAS) was assessed using the marine echinoderm Holothuria tubulosa Gmelin, 1791. Batch experiments were conducted to establish the relationship between concentrations in water, sediment and biota over 197 days. The sample treatment for the determination of compounds involves steps of lyophilization, solvent extraction and clean-up of the extracts with dispersive sorbents. PFAS were then analysed by liquid chromatography-tandem mass spectrometry. During contaminant exposure, detectable levels of compounds were found in all samples collected. Mean concentrations of selected PFAS were higher in sediments than in water samples. This fact is explained by the strong adsorption of these compounds into sediments. Sediment-water distribution coefficients (log Kd) were in the range 0.11 (PFBuA) to 2.46 (PFOA). Beside this, PFAS accumulation was observed in Holothuria tubulosa organisms. The uptake of PFAS was very rapid, reaching the maximum between 22 and 38 days of assay. Bioaccumulation factors (mean log BAF: 1.16-4.39) and biota sediment accumulation factors (mean log BSAF: 1.37-2.89) indicated a high bioaccumulation potential for the target compounds. Both parameters increased with perfluoroalkyl chain length (R2 > 0.93; p < 0.05). In organ-specific distributions of PFAS, greater concentrations were found in intestine than in gonads. Also, male specimens showed higher concentration levels than female (student t-test: tcal = 2.788, ttab = 2.262; p < 0.05). These data provide a detailed accounting of PFAS fate and distribution in the marine environment highlighting accumulation at lower trophic levels, a potential source for contamination in higher organisms.

A critical analysis of published data to discern the role of soil and sediment properties in determining sorption of per and polyfluoroalkyl substances (PFASs)

Widespread usage of per- and polyfluoroalkyl substances (PFASs) has caused major environmental contamination globally. The hydrophilic and hydrophobic properties of PFASs affect the sorption behaviour and suggest organic carbon may not be the only factor affecting sorption. We reviewed the quality of all data published in peer-reviewed literature on sorption of PFASs to critically evaluate the role organic carbon (OC) and other properties have in sorption of PFASs in soils or sediments. The largest data sets available were for perfluorooctanoic acid (PFOA, n = 147) and perfluorooctane sulfonic acid (PFOS, n = 178), and these analyses showed very weak correlations between sorption coefficient (K_d) and OC alone (R² = 0.05-0.07). When only laboratory-derived K_d values of PFASs and OC were analysed, the R² values increased for PFOA (R² = 0.24, n = 42), PFOS (R² = 0.38, n = 69), perfluorononanoic acid (PFNA, R² = 0.77 n = 12), and perfluorodecanoic acid (PFDA, R² = 0.78, n = 13). However, the relationships were heavily skewed by one or two high OC values. Similarly there was no significant relationship between K_d values and pH for PFOS (R² = 0.06) and PFOA (R² = 0.07), across a range of environmental pH values. Our analyses showed sorption behaviour of a range of PFASs could not be explained by a single soil or sediment property. Multiple regression models better explained the sorption behaviour of a number of PFASs. Regressions of OC and pH together explained a significant proportion of the variation in K_d values for 9 out of 14 PFASs and 8 of these regressions had ≥10 data points. This review highlighted that at least OC, pH and clay content are properties having significant effect on sorption. There is a clear need for more data and studies with thorough characterisation of soils or sediments to better understand their role in PFASs sorption. Current assessments based on OC alone are likely to be erroneous.

Spatial and vertical variations of perfluoroalkyl acids (PFAAs) in the Bohai and Yellow Seas: Bridging the gap between riverine sources and marine sinks

Perfluoroalkyl acids (PFAAs) are being increasingly reported as emerging contaminants in riverine and marine settings. This study investigated the contamination level and spatial distribution of 17 PFAAs within the depth profile of the Bohai and Yellow Seas using newly detected sampling data from 49 sites (June 29 to July 14, 2016). Moreover, the riverine flux of 11 selected PFAAs in 33 rivers draining into the Bohai and Yellow Seas was estimated from previous studies (2002-2014) in order to establish the relationship between riverine sources and marine sinks. The results showed that the Bohai and Yellow Seas were commonly contaminated with PFAAs: total concentrations of PFAAs in the surface, middle, and bottom zones ranged from 4.55 to 556 ng L^-1, 4.61-575 ng L^-1, and 4.94-572 ng L^-1, respectively. The predominant compounds were PFOA (0.55-449 ng L^-1), PFBA (<LOQ-34.5 ng L^-1), and PFPeA (<LOQ-54.3 ng L^-1), accounting for 10.1-87.0%, 5.2-59.5%, and 0.6-68.6% of the total PFAAs, respectively. In general, the ∑PFAA concentrations showed a slightly decreasing trend with sampling depth. Contamination was particularly severe in Laizhou Bay, fed by the Xiaoqing River and an industrial park known for PFAA production. The total riverine PFAA mass flux into the Bohai and Yellow Seas was estimated to be 72.2 t y^-1, of which 94.8% was carried by the Yangtze and Xiaoqing Rivers. As the concentration of short-chain PFAAs begins to rise in seawater, further studies on the occurrence and fate of short-chain PFAAs with special focus on effective control measures would be very timely, particularly in the Xiaoqing River and Laizhou Bay.

Distribution of perfluorinated compounds (PFASs) in the aquatic environment of the industrially polluted Vaal River, South Africa

Perfluorinated alkyl substances (PFASs) are highly persistent chemicals, which have a bioaccumulative potential and can be found in wildlife around the world. Although multiple studies have been performed on PFASs pollution of the aquatic environment, little is known on PFASs pollution on the African continent and their possible risks for human health. In the present study, we examined the distribution of 15 PFASs in fish, invertebrates, sediment and water, collected at three sites, representing a gradient of industrial and mining pollution, along the Vaal River, South Africa. Furthermore, possible risks for human health through consumption of contaminated fish were examined. Perfluorooctane sulfonate (PFOS) was the most dominant PFAS measured in biota, whereas perfluoropentanoic acid (PFPeA) was measured in higher concentrations in water. Mean PFAS concentrations in water ranged from <LOQ to 38.5ng/L. PFAS concentrations in water decreased along the gradient and were similar or lower compared to other studies in Europe, Asia and America. PFAS measurements in sediment were <LOQ, with the exception of PFOS at Thabela Thabeng (2.36ng/g dry weight (dw)). Average ∑PFAS concentrations in biota increased along the gradient and ranged from <LOQ to 34.5ng/g wet weight (ww) in invertebrates, <LOQ to 289ng/g ww in liver and <LOQ to 34.0ng/g ww in muscle tissue. Although PFOS concentrations were relatively high compared to literature, concentrations of other PFASs were rather low. A potential risk for humans through consumption of PFAS-contaminated fish was assessed. Tolerable daily intake values (grams of fish that can be eaten daily without risking health effects) were much lower than the average South African fish consumption per day, implying a potential risk for human health through consumption of PFAS contaminated fish. CAPSULE: Concentrations of perfluorinated compounds in water, sediment, fish and invertebrates from the Vaal River were low or intermediate and posed a potential risk for human health through consumption of contaminated fish.

Bioaccumulation of perfluoroalkyl substances in exploited fish and crustaceans: Spatial trends across two estuarine systems

Spatial patterns in perfluoroalkyl substances were quantified for exploited fish and crustaceans across two contrasting Australian estuaries (Port Stephens and Hunter River). Perfluorooctane sulfonate (PFOS) was detected in 77% of composites from Port Stephens and 100% of composites from Hunter River. Most species from Port Stephens showed a clear trend with distance to source. In contrast, only a subset of species showed this trend in the Hunter River, potentially due to species movement patterns and differing hydrology. Spatial modelling showed that PFOS concentrations were expected to exceed the relevant trigger value up to ~13,500 m from the main point source for Port Stephens and ~9000 m for the Hunter River. These results represent the first major investigation of bioaccumulation of PFASs in exploited species in Australian estuaries, and highlight various factors that can contribute to spatial patterns in bioaccumulation.

Bioaccumulation Patterns of Perfluoroalkyl Acids in an Estuary of the Ariake Sea, Japan

To evaluate the bioaccumulation potential of perfluoroalkyl acids (PFAAs) in an aquatic food web, we measured the concentrations of nine PFAAs in the water and aquatic organisms from an estuary of the Omuta River, Japan. Average log bioaccumulation factors for all PFAAs ranged from 2.0 to 2.8. There was no positive correlation observed between PFAA carbon chain length and there was no evidence of trophic magnification demonstrated among the sample types collected. These results differed from the findings of previous studies in enclosed bodies of water, perhaps because river mouth-estuarine ecotones are more variable spatially and temporally and include some fish that are highly migratory. Further investigations of bioaccumulation factors will be needed to elucidate the tendency of amphiphilic chemicals to bioaccumulate in these river mouth-estuarine ecotones.

Assessing the effects of seawater temperature and pH on the bioaccumulation of emerging chemical contaminants in marine bivalves

Emerging chemical contaminants [e.g. toxic metals speciation, flame retardants (FRs) and perfluorinated compounds (PFCs), among others], that have not been historically recognized as pollutants nor their toxicological hazards, are increasingly more present in the marine environment. Furthermore, the effects of environmental conditions (e.g. temperature and pH) on bioaccumulation and elimination mechanisms of these emerging contaminants in marine biota have been poorly studied until now. In this context, the aim of this study was to assess, for the first time, the effect of warmer seawater temperatures (Δ = + 4°C) and lower pH levels (Δ = - 0.4 pH units), acting alone or combined, on the bioaccumulation and elimination of emerging FRs (dechloranes 602, 603 and 604, and TBBPA), inorganic arsenic (iAs), and PFCs (PFOA and PFOS) in two estuarine bivalve species (Mytilus galloprovincialis and Ruditapes philippinarum). Overall, results showed that warming alone or combined with acidification promoted the bioaccumulation of some compounds (i.e. dechloranes 602, 604, TBBPA), but also facilitated the elimination of others (i.e. iAs, TBBPA). Similarly, lower pH also resulted in higher levels of dechloranes, as well as enhanced iAs, PFOA and PFOS elimination. Data also suggests that, when both abiotic stressors are combined, bivalves' capacity to accumulate contaminants may be time-dependent, considering significantly drastic increase observed with Dec 602 and TBBPA, during the last 10 days of exposure, when compared to reference conditions. Such changes in contaminants' bioaccumulation/elimination patterns also suggest a potential increase of human health risks of some compounds, if the climate continues changing as forecasted. Therefore, this first study pointed out the urgent need for further research on the effects of abiotic conditions on emerging contaminants kinetics, to adequately estimate the potential toxicological hazards associated to these compounds and develop recommendations/regulations for their presence in seafood, considering the prevailing environmental conditions expected in tomorrow's ocean.

Comprehensive insights into the interaction mechanism between perfluorodecanoic acid and human serum albumin

In this investigation, we explored the toxic effects of perfluorodecanoic acid (PFDA) on human serum albumin (HSA), established the interaction mode of PFDA with HSA, and provided a new strategy for the evaluation of toxicity of PFDA on functional proteins.

Occurrence and assessment of perfluoroalkyl acids (PFAAs) in commonly consumed seafood from the coastal area of Bangladesh

This study reports the first evidence of the occurrence of PFAAs in commonly consumed seafood from the coastal area of Bangladesh. Fifteen target PFAAs in 48 seafood samples (5 finfish and 2 shellfish species) were measured by HPLC-MS/MS. The ΣPFAAs in finfish and shellfish were in the range of 0.32-14.58 and 1.31-8.34 (ng/g wet weight), respectively. Perfluorooctanesulfonate (PFOS) in finfish (0.1-3.86ng/g ww), whereas perfluorooctanoic acid (PFOA) in shellfish (0.07-2.39ng/g ww) were the most abundant PFAAs. The results were comparable with other studies worldwide, particularly from China, Spain, Sweden, and USA. The majority of monitored PFAAs did not show clear seasonal variation. However, seafood from the southeast area (Cox's Bazar and Chittagong) showed relatively higher levels of PFAAs. Moreover, the dietary exposure assessment revealed that the daily intakes of PFAAs via seafood consumption were far less than the health-based guidelines, indicating low health risk for the Bangladeshi coastal residents.

Evidence for the Trophic Transfer of Perfluoroalkylated Substances in a Temperate Macrotidal Estuary

The present survey examines the trophodynamics of a suite of 19 perfluoroalkyl substances (PFASs) in a temperate macrotidal estuary (Gironde, SW France). Across the 147 biota samples (18 taxa) collected, perfluorooctane sulfonate (PFOS), perfluorooctane sulfonamide (FOSA), and C₈-C₁₄ perfluoroalkyl carboxylates (PFCAs) were the most-recurrent analytes. ΣPFASs ranged between 0.66-45 ng per g of wet weight of the whole body. Benthic organisms had relatively high ΣPFASs compared to demersal organisms and displayed specific composition profiles with higher relative abundances of C₈ and C₉ PFCAs. Trophic magnification factors (TMFs) were determined through the use of linear mixed effect models including censored data, thereby considering data below detection limits as well as the interspecific variability of δ¹⁵N and PFAS levels (random effects). TMFs were almost consistently >1 in the benthic food web as well as when considering all data pooled together, providing evidence for the biomagnification of several PFASs in estuarine environments. In addition, in contrast with previous observations, TMFs determined in the estuarine benthic web were found to significantly decrease with increasing chain length for C₈-C₁₄ PFCAs and C₆-C₈ perfluoroalkyl sulfonates. This suggests that PFAS chemical structure might not be necessarily predictive of TMFs, which are also influenced by the trophic web characteristics.

Recent developments in polyfluoroalkyl compounds research: a focus on human/environmental health impact, suggested substitutes and removal strategies

Between the late 1940s and early 1950s, humans manufactured polyfluoroalkyl compounds (PFCs) using electrochemical fluorination and telomerisation technologies, whereby hydrogen atoms are substituted by fluorine atoms, thus conferring unnatural and unique physicochemical properties to these compounds. Presently, there are wide ranges of PFCs, and owing to their bioaccumulative properties, they have been detected in various environmental matrices and in human sera. It has thus been suggested that they are hazardous. Hence, this review aims at highlighting the recent development in PFC research, with a particular focus on perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS), the most studied and predominantly found PFCs in various environmental matrices, although recent reports have included perfluorobutane sulfonate (PFBS), which was previously regarded as innocuously harmless, when compared to its counterparts, PFOA and PFOS. As such, proper investigations are thus required for a better understanding of short-chain PFC substitutes, which have been suggested as suitable replacements to long-chained PFCs, although these substitutes have also been suggested to pose various health risks comparable to those associated with long-chain PFCs. Similarly, several novel technologies, such as PFC reduction using zero-valent iron, including removal at point of use, adsorption and coagulation, have been proposed. However, regardless of how efficient removers some of these techniques have proven to be, short-chain PFCs remain a challenge to overcome for scientists, in this regard.

Depuration of perfluoroalkyl substances from the edible tissues of wild-caught invertebrate species

Detection and quantification of poly- and perfluoroalkyl substances (PFASs) in aquatic organisms is increasing, particularly for saltwater species. Depuration can remove PFASs from the tissues of some species once they are removed from the contaminant source, but it is not known if this process occurs for saltwater crustaceans. Such information is important for managing human health risks for exploited migratory species following exposure. We present the results of a depuration trial for School Prawn (Metapenaeus macleayi) and Mud Crab (Scylla serrata), two commercially important crustaceans in Australia. Perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), and perfluorooctanoic acid (PFOA) were present in samples of both species collected following exposure under natural conditions in contaminated estuaries. Depuration was tested in uncontaminated water for 33days. PFOA was present at levels close to LOR in both species, and was not detected after 4.5h and 72h in School Prawn and Mud Crab respectively. PFHxS was rapidly depurated by School Prawn, and had a depuration half-life of 5.7h. PFOS was also depurated by School Prawn, with a depuration half-life of 158.5h. PFHxS and PFOS concentrations were highly variable in Mud Crab both at the start, and during the depuration experiment, and a depuration model could not be fitted to the data. For School Prawn, depuration of total PFASs to the relevant screening value for protection of human health (9.1μgkg^-1) occurred within 7.1h. Rapid depuration of PFASs in School Prawn indicates that human health risks associated with consumption may decrease as this species migrates away from the contamination source. Further research is required to better understand the relationships between contaminant load and life-history characteristics (such as growth, reproduction, and moult cycle) in Mud Crab, and future work should target broader time frames for depuration in this species.

Traditional and new POPs in environments along the Bohai and Yellow Seas: An overview of China and South Korea

Rapid economic growth during the past two decades in the region surrounding the Bohai and Yellow Seas has resulted in severe pollution. Large amounts of monitoring data on persistent organic pollutants (POPs) in various environmental media have been accumulated, which allows us to conduct a fairly comprehensive assessment of the region around the Bohai and Yellow Seas to elucidate spatial patterns of pollution on a regional scale. This review summarized distributions of traditional and new POPs, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and perfluoroalkyl substances (PFASs), in various environmental media. In general, due to their physico-chemical properties (poor solubility in water), OCPs and PCBs were mainly detected in sediments, PBDEs and HBCDs were mainly detected in sediments and soils. PFASs, which have greater solubility, were mainly detected in the hydrosphere. For conventional POPs, such as OCPs and PCBs, Bohai Bay and Haihe River in China, Gyeonggi Bay and Lake Sihwa in South Korea were found to be most polluted areas. While for new POPs, such as PBDEs, HBCDs and PFASs, some areas were heavily polluted due to local production and applications. Estuarine and coastal areas of the Bohai Sea were more severely contaminated by POPs than coastal regions of the Yellow Sea. Overall, the present review will guide identification of key areas for strengthening risk assessment of POPs and management practices.

Fatty acid metabolism in fish species as a biomarker for environmental monitoring

Pollution by Organic Contaminants (OC) in aquatic environments is a relevant issue at the global scale. Lipids comprised of Fatty Acids (FA) play many important roles in the physiology and life history of fishes. Toxic effects of OC are partly dependent on its bioaccumulation in the lipids of aquatic organisms due its physicochemical properties. Therefore, there is an increasing interest to investigate the gene expression as well as the presence and activity of proteins involved in FA metabolism. The attention on Peroxisome Proliferation Activate Receptors (PPARs) also prevails in fish species exposed to OC and in the transport, biosynthesis and β-oxidation of FA. Several studies have been conducted under controlled conditions to evaluate these biological aspects of fish species exposed to OC, as fibrates, endocrine disrupting compounds, perfluoroalkyl acids, flame retardants, metals and mixtures of organic compounds associated with a polluted area. However, only fibrates, which are agonists of PPARs, induce biological responses suitable to be considered as biomarkers of exposure to these pollutants. According to the documented findings on this topic, it is unlikely that these physiological aspects are suitable to be employed as biomarkers with some noticeable exceptions, which depend on experimental design. This emphasises the need to investigate the responses in fish treated with mixtures of OC and in wild fish species from polluted areas to validate or refute the suitability of these biomarkers for environmental or fish health monitoring.

Elevated levels of short carbon-chain PFCAs in breast milk among Korean women: Current status and potential challenges

Breast milks can be contaminated with perfluoroalkyl substances (PFASs). Exposure to PFASs during early stages of life may lead to adverse health effects among breastfed infants. To date, perfluorootanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been most frequently measured PFASs in breast milks worldwide. Information on shorter carbon-chain PFASs in breast milk is scarce. In this study, breast milks were sampled from 264 Korean lactating women, and measured for seventeen PFASs, including ten perfluoroalkyl carboxylates (PFCAs), four perfluoroalkyl sulfonates, and three perfluoroalkyl sulfonamides. PFOA and PFOS were detected in 98.5% of the breast milk samples, with median concentrations of 0.072 and 0.050ng/mL, respectively. Perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), and perfluoroheptanoic acid (PFHpA) were detected in higher frequencies, ranging between 67.4% and 81.8%. The concentrations of short carbon-chain PFCAs in breast milk such as PFPeA and PFHxA were the highest ever reported to date, and were comparable to that of PFOS. Concentrations of shorter chain PFCA in breast milk tended to be higher among the women with longer lactation period, while those of PFOA showed the opposite trend, suggesting a possibility that breastfeeding might be an important route of excretion for PFOA among lactating women. Fish consumption and the use of consumer products, e.g., skin care products, cosmetics and non-stick coated cooking utensils, were identified as significant predictors of PFAS concentrations in breast milk. Health risks associated with PFOA and PFOS exposure through breastfeeding were estimated negligible, however, risks of the short carbon-chain PFCAs could not be assessed because of lack of relevant toxicological information. Further efforts for source identification and exposure management measures for shorter chain PFCAs are necessary.