How do measured PBDE and HCBD levels in river fish compare to the European Environmental Quality Standards?

The Interplay of Persistent Organic Pollutants and Mediterranean Diet in Association With the Risk of Gestational Diabetes Mellitus

OBJECTIVE

Certain foods characterizing the alternate Mediterranean diet (aMED) are high in persistent organic pollutants (POPs), which are related to greater gestational diabetes mellitus (GDM) risk. We examined the associations of combined aMED and POP exposure with GDM.

RESEARCH DESIGN AND METHODS

aMED score of 1,572 pregnant women was derived from food frequency questionnaires at early pregnancy within the U.S. Fetal Growth Study and plasma concentrations of 76 POPs, including organochlorine pesticides, polybrominated diphenyl ethers, polychlorinated biphenyls (PCBs), and per- and polyfluoroalkyl substances, were measured. Associations of combined aMED score and exposure to POPs with GDM risk were examined by multivariable logistic regression models.

RESULTS

In 61 of 1,572 (3.88%) women with GDM, 25 of 53 included POPs had a detection rate >50%. Higher POP levels appeared to diminish potential beneficial associations of aMED score with GDM risk, with the lowest GDM risk observed among women with both high aMED score and low POP concentrations. Specifically, adjusted log-odds ratios of GDM risk comparing women with low PCB and high aMED score with those with low aMED score and high PCB concentrations was -0.74 (95% CI -1.41, -0.07). Inverse associations were also observed among women with low aMED score and high TransNo_chlor, PCB182_187, PCB196_203, PCB199, and PCB206. These associations were more pronounced among women with overweight or obesity.

CONCLUSIONS

Pregnant women who consumed a healthy Mediterranean diet but had a low exposure to POP concentrations had the lowest GDM risk. Future endeavors to promote a healthy diet to prevent GDM may consider concurrent POP exposure.

Inconsistencies in the EU regulatory risk assessment of PFAS call for readjustment

Recognition of per- and polyfluoroalkyl substances (PFAS) as widespread environmental pollutants and a consequent risk to human health, has recently made the European Union (EU) adopt several regulatory measures for their management. The coherence of these measures is challenged by the diversity and the ubiquitous occurrence of PFAS, which also complicates the EU's endeavor to advance justified, harmonized, and transparent approaches in the regulatory assessment of chemical risks. Our study critically reviews the European approach for the risk assessment of PFAS, by applying a comparative analysis of the current and pending regulatory thresholds issued for these chemicals in water bodies, drinking water, and certain foodstuffs. Our study shows that the level of health protection embedded in the studied thresholds may differ by three orders of magnitude, even in similar exposure settings. This is likely to confuse the common understanding of the toxicity and health risks of PFAS and undermine reasonable decision-making and the equal treatment of different stakeholders. We also indicate that currently, no consensus exists on the appropriate level of required health protection regarding PFAS and that the recently adopted tolerable intake value in the EU is too cautious. Based on our analysis, we propose some simple solutions on how the studied regulations and their implicit PFAS thresholds or their application could be improved. We further conclude that instead of setting EU-wide PFAS thresholds for all the environmental compartments, providing the member states with the flexibility to consider case-specific factors, such as regional background concentrations or food consumption rates, in their national regulatory procedures would likely result in more sustainable management of environmental PFAS without compromising the scientific foundation of risk assessment, the legitimacy of the EU policy framework and public health.

Twenty years later: PBDEs in fish from U.S. sites with historically extreme contamination

Shortly after their production ban PBDE environmental levels retreated from their peak (circa 2000), but rates of decrease appear to be slowing. Therefore, to update environmental PBDE trends, this study re-examined a U.S. riverine system found in 1999 to have the highest PBDE fish tissue (fillet) burdens in the world. Archived 2018-2020 fish tissues were analyzed for PBDEs and results compared to 1999-2000 and 2007 levels. On a positive note, levels decreased by >75% over 20 years. However, PBDEs were still detectable at each collection site (n = 16) and in 93% of the samples. The highest PBDE level (16,300 ng g-1 lipid weight) was observed in fish from the Dan R., downstream from the Hyco R. (where the world's highest level was previously reported). Levels within Hyco R. fish have declined at an annual rate of 30% through 2007. However, reductions during the subsequent 12 years have diminished to only 1.2%. Fillet levels since 2007 actually increased at an estimated annual rate of 8% immediately downstream from the Hyco R. Congener profiles varied between species, likely due to hepatic enzyme debromination, indicating single congener-based health risk evaluations may not be sufficiently protective. Within North America, PBDE fish levels in this freshwater system were twice those of North America's Great Lakes and exceeded by 10-fold those in carp examined from Illinois, USA., another historical hotspot. Average fish PBDE levels also exceed maxima observed in European and Asian riverine systems and were 1000's of times higher than the environmental quality standard (EQS) set by European Parliament (0.0085 ng g-1 wet weight, aquatic biota). Therefore, to protect human health and the environment, PBDE monitoring should remain a priority for regulatory agencies with the goal to identify and eliminate their source and to consider their potential health impacts in the context of other co-existing (emerging and legacy) contaminants.

Varying temporal trends in the levels of six groups of legacy persistent organic pollutants (POPs) in liver of three gadoid species from the North Sea

From 2005 to 2019, three gadoid species, Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus) and saithe (Pollachius virens), were sampled approximately every third year in the northeastern part of the North Sea. Liver samples were analyzed to investigate levels and temporal trends of six groups of persistent organic pollutants (POPs): polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its degradation products, hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), trans-nonachlor (TNC), and polybrominated diphenyl ethers (PBDEs). Some of the highest average concentrations were found in cod, the levels otherwise being similar between the three species and mostly below established threshold values. The levels of all the contaminants except HCB and TNC were higher than previously reported for cod and haddock in the Barents Sea. Significantly decreasing levels were found for Σ7PCBs, ΣDDTs, ΣHCHs and Σ15PBDEs in all three species, and for TNC in haddock and saithe, while there was no significant trend for TNC in cod. HCB levels increased significantly in cod and haddock and showed only a minor decrease in saithe. The observed time trends of legacy POPs demonstrate the persistence of some of the studied pollutants despite efforts to eliminate them from the marine environment.

Bioaccumulation Behavior and Human Health Risk of Polybrominated Diphenyl Ethers in a Freshwater Food Web of Typical Shallow Lake, Yangtze River Delta

BACKGROUND

Polybrominated diphenyl ethers (PBDEs) have been commonly found in aquatic ecosystems. Many studies have elucidated the bioaccumulation and biomagnification of PBDEs in seas and lakes, yet few have comprehensively evaluated the bioaccumulation, biomagnification, and health risks of PBDEs in shallow lakes, and there is still limited knowledge of the overall effects of biomagnification and the health risks to aquatic organisms.

METHODS

In this study, a total of 154 samples of wild aquatic organism and environmental samples were collected from typical shallow lakes located in the Yangtze River Delta in January 2020. The concentrations of PBDEs were determined by an Agilent 7890 gas chromatograph coupled and an Agilent 5795 mass spectrometer (GC/MS) and the bioaccumulation behavior of PBDEs was evaluated in 23 aquatic organisms collected from typical shallow lakes of the Yangtze River Delta. Furthermore, their effects on human health were evaluated by the estimated daily intake (EDI), noncarcinogenic risk, and carcinogenic risk.

RESULTS

The concentrations of ΣPBDE (defined as the sum of BDE-28, -47, -100, -99, -153, -154, -183, and -209) in biota samples ranged from 2.36 to 85.81 ng/g lipid weight. BDE-209, BDE-153 and BDE-47 were the major PBDE congeners. The factors affecting the concentration of PBDEs in aquatic organisms included dietary habits, species, and the metabolic debromination ability of the PBDE congeners. BDE-209 and BDE-47 were the strongest bioaccumulative PBDE congeners in aquatic organisms. Additionally, except for BDE-99, BDE-153 and BDE-154, the trophic magnification factor (TMF) values of PBDE congeners were significantly higher than 1. Moreover, the log Kow played a significant role in the biomagnification ability of PBDE congeners. The noncarcinogenic risk of PBDE congeners and carcinogenic risk of BDE-209 from aquatic products were lower than the thresholds.

CONCLUSIONS

PBDE congeners were bioaccumulated and biomagnified to varying degrees in aquatic organisms from typical shallow lakes. Both the noncarcinogenic and carcinogenic risks assessment of edible aquatic products indicated that none of the PBDE congeners pose health risks to the localite. This study will provide a basis for a comprehensive assessment of PBDEs in aquatic ecosystems in shallow lakes and for environmental prevention measures for decision-makers.

Metal(loid)s and persistent organic pollutants in yellow European eel from the Raša River, Croatia

The anthropogenic impact on the aquatic environment of the Raša River (Croatia) was investigated through the analysis of seven polybrominated diphenyl ethers (PBDEs), seven polychlorinated biphenyls (PCBs), three DDT isomers, and 22 major and trace elements using yellow European eel (Anguilla anguilla L.) as a biological indicator of contamination. The obtained data indicated generally low contamination status in the surrounding area. Levels of all organic contaminants in muscle significantly increased with lipid content, length, weight and body condition. In both muscle and liver, most metal(loid)s decreased or remained unchanged with increasing size, while at downstream location only several elements (Cd, Cu, Fe, Na, Se, U, V, Zn) accumulated in the liver with fish growth. Spatial analysis revealed higher pressure of Ag, Cd, Cr, Mo, Tl, U, and V at the downstream location, revealing the potentially limited impact of historical coal mining industry on the lower reaches of the Raša River.

Maternal Transfer and Apical and Physiological Effects of Dietary Hexabromocyclododecane Exposure in Parental Fathead Minnows (Pimephales promelas)

Hexabromocyclododecane (HBCD) is a persistent organic pollutant that has been characterized as an endocrine disruptor, undergoes maternal transfer, and hinders development and growth in oviparous organisms. The present study examined the apical effects of dietary HBCD (11.5, 36.4, 106 mg/kg, wet wt) on adult fathead minnow exposed for 49 days and the subsequent accumulation and maternal transfer kinetics in adult tissue and eggs, respectively. Exposed adults displayed a significant increase in egg production in the medium treatment group, but no other significant effects were noted. Maternal transfer of dietary HBCD had a similar egg-to-muscle ratios (EMR) in the low and medium treatment groups (1.65 and 1.27 [wet wt], respectively). However, the high treatment group deviated from other treatments with an EMR of 4.2 (wet wt), potentially due to differences in total lipid content in food and/or reaching diffusion/lipid saturation limits in adult tissue, resulting in lower accumulation in the adult muscle tissue. A positive correlation was observed between egg HBCD concentration and time of exposure, which indicates that maternal transfer of HBCD is of concern in fish, and further studies should be conducted to fully elucidate the potential adverse effects that may be observed in the early life stage of oviparous organisms. Environ Toxicol Chem 2023;42:143-153. © 2022 SETAC.

Comprehensive evaluation of the toxicity of the flame retardant (decabromodiphenyl ether) in a bioindicator fish (Gambusia affinis)

In recent years, concerns have increased about the adverse effects on health and the environment of polybrominated diphenyl ethers (PBDEs), especially BDE-209, the most widely PBDE used globally. These pollutants derive from e-waste and present different adverse effects on biota. In this work, a toxicological study on mosquitofish (Gambusia affinis) using BDE-209 (2,2',3,3',4,4',5,'5',6,6'-decabromodiphenyl ether) was carried out. Acute toxicity bioassays were conducted with daily renewal of solutions, using different concentrations of environmental relevance, ranged between 10 and 100 μg L^-1 of BDE-209. At 48 and 96 h of exposure, several parameters were evaluated, such as mortality, individual activity (swimming), biochemical activity (catalase; thiobarbituric acid-reactive substances; and acetylcholinesterase), and cytotoxic responses (micronucleus frequencies). In addition, integrated biomarker response and multivariate analyses were conducted to study the correlation of biomarkers. The calculated Lethal Concentration-50 remained constant after all exposure times (24 to 96 h), being the corresponding value 27.79 μg L^-1 BDE-209. Furthermore, BDE-209 induced effects on the swimming activity of this species in relation to acetylcholine, since BDE-209 increased, producing oxidative damage at the biochemical level and genotoxicity after 48 h of exposure to 10 and 25 μg L^-1 BDE-209. The results indicate that BDE-209 has biochemical, cytotoxic, neurotoxic, and genotoxic potential on G. affinis. In addition, mosquitofish could be used as a good laboratory model to evaluate environmental stressors since they could represent a risk factor for Neotropical species.

Spatiotemporal Trends of Legacy and Alternative Flame Retardants in Harbor Seals from the Coasts of California, the Gulf of Maine, and Sweden

Temporal trends of polybrominated diphenyl ethers (PBDEs) have been extensively studied in various environmental compartments globally. However, despite the increasing use of alternative flame retardants following PBDE bans, the spatiotemporal trends of these replacements have rarely been studied, and the available results are often inconsistent. In the present study, we retrospectively investigated the spatiotemporal trends of PBDEs and a suite of alternative brominated FRs (aBFRs) and chlorinated FRs (i.e., dechloranes or DECs) in three harbor seal (Phoca vitulina) populations from the coasts of California, the Gulf of Maine, and southern Sweden during 1999-2016. We observed significantly decreasing trends of ΣPBDEs in all the three populations at an annual rate of 9-11%, which were predominantly driven by the declining concentrations of tetra- and penta-BDEs. The levels of ΣaBFRs decreased significantly in seals from California (mainly 1,3,5-tribromobenzene) and Sweden (mainly hexabromobenzene), while no trend was observed for those from Maine. By contrast, DECs (dominated by DEC 602) did not decrease significantly in any population. Compared with the consistent PBDE congener profiles across regions, aBFRs and DECs exhibited varying compositional profiles between regions, likely indicating region-specific sources of these alternative FR mixtures. Spatial analysis also revealed regional differences in the concentrations of PBDEs, aBFRs, and DECs in harbor seals. Our reconstructed spatiotemporal trends suggest the effective regulation of commercial penta-BDE mix in these regions and warrant further monitoring of the higher brominated BDEs and alternative FRs.

Tissue concentrations of per- and polyfluoroalkyl substances (PFAS) in German freshwater fish: Derivation of fillet-to-whole fish conversion factors and assessment of potential risks

The European Water Framework Directive requires monitoring of bioaccumulative contaminants in fish to assess risks to human health by fish consumption and wildlife by secondary poisoning of predators. The list of priority substances for which environmental quality standards (EQSs) have been derived covers also perfluorooctane sulfonic acid (PFOS). No EQSs have yet been set for other per- and polyfluoroalkyl substances (PFAS) that are frequently detected in fish and of which some have a non-negligible risk potential compared to PFOS. As a case study, burdens for a set of PFAS were investigated for different fish species from five German freshwater sites and a Baltic Sea lagoon. PFAS concentrations were determined for composite samples of both, fillet and whole fish. On average, sum concentrations of C9-C14 perfluoroalkyl carboxylic acids, which will be banned in the European Union in 2023, reached 87% and 82% of the PFOS burdens in fillet and whole fish, respectively. The potential risk of several PFAS other than PFOS was assessed using a previously suggested relative potency factor approach, which is also applied for a proposed EQS revision. Only five of 36 fillet samples (mostly perch) exceeded the current EQS for PFOS alone. By contrast, all fillet samples exceeded the newly proposed draft EQS, which considers potential effects of further PFAS but also a lower tolerable intake value. Additionally, the dataset was used to derive fillet-to-whole fish conversion factors, which can be applied to assess human health risks by consumption of fillet if only whole fish concentrations are available.

The relevance of European Biota Quality Standards on the ecological water quality as determined by the multimetric macro-invertebrate index: A Flemish case study

European Biota Quality Standards (EQS_biota), for compounds with low water solubility and high biomagnification, were created to sustain water quality and protect top predators and humans from secondary poisoning. In reality, for multiple compounds, an exceedance of these standards is often reported in literature without a decrease in ecological water quality determined by biotic indices. In the present study, threshold concentrations were defined in biota (from 44 sampling locations throughout Flanders (Belgium)), above which a good ecological water quality, assessed by the Multimetric Macroinvertebrate Index Flanders (MMIF), was never reached. Threshold values were compared to current EQS_biota. Accumulated perfluoroctane sulfonate (PFOS), mercury (Hg), hexabromocyclododecane (HBCD), polybrominated diphenyl ethers (PBDEs), dioxins and polychlorinated biphenyls (PCBs) concentrations were measured in muscle tissue of European yellow eel (Anguilla anguilla) and perch (Perca fluviatilis). Fluoranthene and benzo(a)pyrene were also analyzed in translocated mussels (Dreissena bugensis, D. polymorpha and Corbicula fluminea). Threshold values could only be calculated using a 90th quantile regression model for PFOS (in perch; 12 µg/kg ww), PCBs (in eel; 328 µg/kg ww) and benzo(a)pyrene (in mussels: 4.35 µg/kg ww). The lack of a significant regression model for the other compounds indicated an effective threshold value higher than the concentrations measured in the present study. Alternatively, the 95th percentile of concentrations measured in locations with a good ecological quality (MMIF≥0.7), was calculated for all compounds as an additional threshold value. Finally, fish concentrations were standardized for 5% lipid content (or 26% dry weight content for PFOS and Hg). Threshold values for PFOS and benzo(a)pyrene and the 95th percentiles for dioxins and fluoranthene were comparable to the existing standards. For all other compounds, the 95th percentile was higher than the current EQS_biota, while for HBCD, it was lower. These results strongly advise revising and fine-tuning the current EQS_biota, especially for ∑PBDE and HBCD.

Analysis of brominated flame retardants in the aquatic environment: a review

The most common and consequently analysed brominated flame retardants (BFRs) are polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A (TBBPA), tetrabromobisphenol S (TBBPS), and hexabromocyclododecane (HBCD). As these persistent organic pollutants are widespread in the environment and have a number of harmful effects on human health, the production and use of most has been banned for several years. The aquatic environment is polluted by these compounds through their deposition from the atmosphere, sewage sludge, wastewater treatment plants, and landfills, and higher levels are found in areas with developed industry and agriculture and near landfills. Each compound also seems to show preference for specific compartments of the aquatic environment, i.e. water, sediment, or aquatic organisms, according to their physicochemical properties. The aim of this review was to take a closer look at the analysis of BFRs, as without reliable analysis we would not be able to determine their levels and distribution across the aquatic compartments and assess human exposure and health risks. Particularly worrying are the health risks associated with PBDEs in fish, whose levels generally exceed the permitted values.

A comprehensive evaluation of two sample treatment procedures for the determination of emerging and historical halogenated flame retardants in biota

Two different sample preparation protocols for the determination of 37 emerging and historical halogenated flame retardants (HFRs) in marine tissues were compared with regards to extraction recovery, lipid removal efficiency, repeatability, reproducibility, and ability to measure sub-ng g-1 (dry weight) concentrations in marine biota. One method involved a purification step using gel permeation chromatography (GPC) followed by a HPLC fractionation step on a Partisil amino-cyano normal phase (GPC-Partisil procedure) and the other more traditional method was based on sulphuric acid treatment followed by silica column fractionation (H2SO4-silica procedure). The samples were analysed by gas chromatography (GC) and liquid chromatography (LC) tandem mass spectrometry (MS/MS). Sample fractionation in both methods enabled unique sample preparation procedures to isolate the GC from the LC amenable compounds. Both methods could remove > 99% of the lipids which was necessary prior to GC- and LC-MS/MS analyses. The majority of the target compounds (70%) had acceptable recoveries between 60-120% for both methods. However, the sulphuric acid treatment resulted in the degradation of the TBP-AE and the silica column fractionation resulted in the loss of BEH-TEBP and the elution of PBB-Acr and TBBPA-BME in the unsuitable fraction. High recoveries of DBE-DBCH (α+β), EHTBB, BTBPE, BEH-TEBP, and PBB-Acr were attributed to matrix effects, suggesting the need to use isotope-labelled surrogate standards of the target compounds. The optimisation of the silica column chromatography, GPC, and Partisil fractionation is described and discussed to afford easy implementation of the method. The method using GPC followed by Partisil fractionation is more efficient and more reproducible than the sulphuric acid-silica procedure. The application of this method to marine biota reference materials revealed the presence of relatively high concentrations of DBE-DBCH isomers and BDE-47 in fish samples. The method detection limits comply with the recommendations of the European Commission.

State of the art in the analysis of brominated flame retardants in biota and sediment: insights from the characterisation of two new certified reference materials

The Joint Research Centre (JRC) of the European Commission has recently released two new Certified Reference Materials (CRMs) for the analysis of brominated flame retardants (BFRs): the freshwater sediment ERM-CC537a and the fish tissue ERM-CE102. The production of these CRMs responds to the need of expanding the offer of quality assurance/quality control tools for the analysis of BFRs in the fields of environmental analysis and food control, especially for compliance purposes. The sediment ERM-CC537a carries certified values for polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD) diastereoisomers in the μg/kg range (dry mass), while the fish tissue ERM-CE102 is certified for PBDEs in the ng/kg range (wet weight). ERM-CC537a is the first reference material ever available with certified values for α-, β- and γ-HBCDD. The assignment of the certified values was performed via an intercomparison of expert laboratories. The evaluation of the data confirms the improving trend, observed in recent years, regarding the comparability of PBDE measurement results. The relative standard deviation (RSD) among laboratories is slightly better for the fish material (8-11%) compared to the sediment (9-15%), despite lower mass fractions in the biota matrix. The RSD of HBCDD data (17%) reveals that they are more challenging analytes. The average measurement uncertainty declared by the participants is about 30%, but an in-depth analysis of their performance reveals that it should be feasible to reduce the uncertainty budget.

Update of the risk assessment of hexabromocyclododecanes (HBCDDs) in food

The European Commission asked EFSA to update its 2011 risk assessment on hexabromocyclododecanes (HBCDDs) in food. HBCDDs, predominantly mixtures of the stereoisomers α-, β- and γ-HBCDD, were widely used additive flame retardants. Concern has been raised because of the occurrence of HBCDDs in the environment, food and in humans. Main targets for toxicity are neurodevelopment, the liver, thyroid hormone homeostasis and the reproductive and immune systems. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour in mice can be considered the critical effects. Based on effects on spontaneous behaviour in mice, the Panel identified a lowest observed adverse effect level (LOAEL) of 0.9 mg/kg body weight (bw) as the Reference Point, corresponding to a body burden of 0.75 mg/kg bw. The chronic intake that would lead to the same body burden in humans was calculated to be 2.35 μg/kg bw per day. The derivation of a health-based guidance value (HBGV) was not considered appropriate. Instead, the margin of exposure (MOE) approach was applied to assess possible health concerns. Over 6,000 analytical results for HBCDDs in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary LB exposure to HBCDDs were fish meat, eggs, livestock meat and poultry. The CONTAM Panel concluded that the resulting MOE values support the conclusion that current dietary exposure to HBCDDs across European countries does not raise a health concern. An exception is breastfed infants with high milk consumption, for which the lowest MOE values may raise a health concern.

BFRs (PBDEs and HBCDs) in freshwater species from Lake Trasimeno (Italy): The singular case of HBCDs in red swamp crayfish

Eighty-six samples belonging to five different species (crucian carp, Carassius carassius; European perch, Perca fluviatilis; tench, Tinca tinca; eel, Anguilla anguilla; red swamp crayfish, Procambarus clarkii) collected from Lake Trasimeno (Italy) were analyzed to assess polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) contamination. The Trasimeno is the largest Italian peninsular lake located in Umbria (Central Italy), in a rural area with low anthropogenic impact. All the samples were analyzed by an in-house developed analytical procedure involving a single sample preparation with dual detection: Gas- and Liquid-Chromatography coupled to tandem Mass Spectrometry (GC-MS/MS for PBDEs and LC-MS/MS for HBCDs). BFRs levels in crucian carp, tench and European perch were negligible and mostly below quantification limits (LOQs). In eel, the species with the higher fat content, PBDE sum (15 congeners) ranged from 0.269 to 0.916 ng/g w.w. BDE-47, -100 and -154 accounted for roughly 57%, 16% and 11% of the PBDE sum, respectively, while BDE-99 (usually one of the most abundant congeners in biota), only for 3%. HBCDs (sum of α-, β-, γ-isomers) were found between 0.157 and 1.14 ng/g w.w. with α- as predominant isomer (92% of the sum), followed by γ- (5%) and β- (2%). Peculiar was the contamination in red swamp crayfish characterized by negligible PBDEs and very high HBCDs levels with a singular contamination pattern. In female pools (n = 9) the mean HBCDs sum was 0.150 ng/g w.w., while in males higher concentrations were measured (mean = 2.77 ng/g w.w.). A significant correlation seems to exist between the contamination level and the seasonal cycle only in male crayfish. Interestingly, among the HBCDs, the γ-isomer was the highest (67% of the total) while α- contributes only for 20%.

Evaluation of Environmental Quality of Mediterranean Coastal Lagoons Using Persistent Organic Pollutants and Metals in Thick-Lipped Grey Mullet

The evaluation of past and present anthropogenic impacts affecting the ecological quality status of transitional ecosystems is crucial from the perspective of protecting them from further deterioration, and to evaluate remediation and restoration measures. Contamination patterns of thick-lipped grey mullet from two Mediterranean coastal lagoons within a protected area in Italy were assessed and compared in order to evaluate their overall quality status and to collect information that can provide useful feedback on management choices aimed at enhancing environmental quality and biodiversity conservation. The quality status of the two lagoons was evaluated by an environmental assessment methodology based on indicators of direct and indirect human pressures, while a broad range of analyses were carried out to determine the presence and concentration of persistent organic pollutants (POPs) and metals in fish muscle tissue. A good quality status resulted for both lagoons, and an overall limited anthropogenic impact in the surrounding area. This could account for POPs and metal contamination levels found in mullet, although limited, and relating to their patterns. The overlap of results achieved with the two evaluation approaches can provide support for management choices in Mediterranean lagoon environments, especially for those committed to the protection and conservation of biodiversity.

Quality assessment of escaping silver eel (Anguilla anguilla L.) to support management and conservation strategies in Mediterranean coastal lagoons

Silver eel samples, collected from the lagoons of Fogliano and Caprolace (Italy), were investigated for a broad range of contaminants (29 polychlorinated biphenyls, 9 polybrominated diphenyl ethers, 5 dichlorodiphenyltrichloroethane, 5 chlordanes, hexachlorobenzene, 3 hexachlorocyclohexane, and 5 metals). Concentrations of targeted compounds stand for a general low contamination pattern. Infestation by Anguillicola crassus and virus infections were also examined. No parasite infestation was found, while infected silver eels had a low prevalence for EVEX, and, for the first time in the Mediterranean area, for AngHV-1. Overall, a good quality status of escaping silver eels, for both lagoons, was highlighted by the use of integrative Indexes. A quality assessment of the ecological status of the two lagoons was carried out developing an expert judgment approach, in order to characterize the habitat of eel stocks. A Final Pressure Index was derived, whose values showed an overall limited global anthropogenic impact acting on both lagoons. Results stand for the suitability of an integrated approach to assess lagoon habitats and eel local stocks quality. This could be proposed as a tool to identify sites yielding high quality eel spawners in the Mediterranean region, in order to set up suitable management frameworks, providing elements to appraise and discuss the potential of coastal lagoons in the Mediterranean region towards the recovery of the eel global stock.

Concentrations and Long-Term Temporal Trends of Hexabromocyclododecanes (HBCDD) in Lake Trout and Walleye from the Great Lakes

Hexabromocyclododecane (HBCDD) is a hazardous, persistent, bioaccumlative brominated flame retardant. To investigate how its use has affected the Great Lakes, total HBCDD (∑HBCDD) concentrations and temporal trends in homogenized whole fish samples from the Great Lakes region (1978 to 2016) were determined. ∑HBCDD concentrations (ng/g ww) for each lake are Erie (0.49-2.60), Ontario (3.12-8.90), Michigan (3.91-9.01), Superior (5.69-13.1), and Huron (5.57-13.7). Early years (1978 to 1992) showed no significant trend. However, recent trends (2004 to 2016) suggest concentrations are increasing in Lakes Erie and Ontario, decreasing in Lakes Superior and Michigan, and not changing in Lake Huron. Decreasing trends for Lakes Superior and Michigan are likely the result of decreased usage of the compound globally, regionally, and locally. For the other lakes, increasing or zero trends are consistent with food web changes due to invasive species and climate change, which has caused more intense storms and less ice cover leading to increased sediment resuspension.

The occurrence of polybrominated diphenyl ethers and their metabolites in Portuguese river biota

This study focused on the assessment of polybrominated diphenyl ethers (PBDEs) and their methoxylated metabolites (MeO-PBDEs) in estuarine seafood from the main Portuguese river, in order to evaluate their impact in the environment and the safety of consumers' health, thus providing a comparison with other world regions. For the purpose, PBDEs and MeO-PBDEs were determined in several seafood species collected along the Tagus estuary region, Portugal, in two catching seasons of 2019. The analyses were performed by an environmental-friendly method comprising a QuEChERS-based extraction with subsequent gas chromatography (tandem) mass spectrometry detection. Only trace amounts of BDE-47 (up to 2.0 ng·g^-1 wet weight) were found in the muscle of lower trophic levels fish species, i.e. mullet and common barbel, collected in the spring. All remaining targeted PBDEs and MeO-PBDEs were below the limits of quantification, which is indicative of a reduced environmental contamination, as well as a low risk of exposure to PBDEs and MeO-PBDEs through the consumption of these species. These amounts are smaller than other regions worldwide and therefore indicative of a low contamination level in Portuguese waters.

Emergent contaminants in sediments and fishes from the Tamsui River (Taiwan): Their spatial-temporal distribution and risk to aquatic ecosystems and human health

The occurrence of emergent contaminants, 24 polybrominated diphenyl ethers (PBDEs), di(2-ethylhexyl)phthalate (DEHP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), diethyl phthalate (DEP), dimethyl phthalate (DMP), di-n-octyl phthalate (DnOP), bisphenol A (BPA) and nonylphenol (NP), was investigated in sediments and fishes collected from the Tamsui River system to determine the factors that influence their distribution and their risk to aquatic ecosystems and human health. The concentrations of total PBDEs, DEHP, DBP, BBP, DEP, DMP, DnOP, BPA and NP in sediments were 1-955, ND-23570, <50-411, <50-430, ND-80, ND-<50, ND-<50, 1-144, 3-19624 μg/kg dw, respectively. The spatial-temporal distribution trends of these compounds in sediments could be attributed to urbanization, industrial discharge and effluents from wastewater treatment plants. The PBDE congener distribution patterns (BDE-209 was the dominant congener) in sediments reflected the occurrence of debromination of BDE-209 and the elution of penta-BDE from the treated products. The concentrations of total PBDEs, DEHP, DBP, BBP, DEP, DMP, DnOP, BPA and NP in fish muscles were 2-66, 17-1046, <10-231, <10-66, <30, ND-<30, ND-<30, 0.4-7 and 3-440 μg/kg ww, respectively. The species-specific bioaccumulation of these compounds by fish was found and four species particularly showed high bioaccumulation potential. BDE-47 was the predominant BDE congener in fish muscles, suggesting high bioavailability and bioaccumulation of this compound. The results of biota-sediment accumulation factors showed that BDE-47, 99, 100, 153 and 154 had relatively high bioavailability and bioaccumulation potential for some fish species. The ecological risk assessment showed that the concentrations of BPA and NP in sediments were likely to have adverse effects on aquatic organisms (risk quotients > 1). The human health risk assessment according to hazard quotients (HQs) and carcinogenic risks (CRs) revealed no remarkable risk to human health through consumption of fish contaminated with BDE-47, 99, 100, 154, 209, DEHP, BPA and NP.

Levels and distribution of polybrominated diphenyl ethers in humans and environmental compartments: a comprehensive review of the last five years of research

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants (BFRs), present in the environment, animals, and humans. Their levels, distribution, and human exposure have been studied extensively, and over the last decade, various legal measures have been taken to prohibit or minimize their production and use due to the increasing amount of evidence of their harmful effects on human and animal health.Our aim here was to make a comprehensive and up-to-date review of the levels and distribution of PBDEs in the aquatic environment, air, and soil, in indoor dust, and in humans. To fulfill this, we searched through Web of Science for literature data reported in the last five years (2015-2019) on levels of at least six key PBDE congeners in abovementioned matrices. According to our summarized data, significant PBDE mass concentrations/fractions are still being detected in various sample types across the world, which implies that PBDE contamination is an ongoing problem. Secondary sources of PBDEs like contaminated soils and landfills, especially those with electronic and electrical waste (e-waste), represent a particular risk to the future and therefore require a special attention of scientists.

Decreasing but still high levels of halogenated flame retardants in wetland birds in central Spain

The occurrence of classical and emerging halogenated flame retardants in bird samples collected between 2010-17 from the Castrejón reservoir (central Spain) was studied. Different wetland bird samples were analysed, including unhatched bird eggs and liver of dead nestlings. Polybrominated diphenylethers (PBDEs) were detected in all the samples at high concentration values, with levels up to 5167 ng/g lw. Dechloranes were found in 78% of analysed samples, but at lower concentration levels, between not detected (nd) and 2153 ng/g lw. The time trend evaluation over the sampling period showed an approximately 50% decline in mean concentrations of PBDEs. However, the most recent data for PBDEs (2016-17) still indicate that, in some cases, and based on reported LOECs, wetland birds were exposed to PBDE concentrations that are associated with possible ecological hazards.

Levels and temporal trends of persistent organic pollutants (POPs) in Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) from the southern Barents Sea

Liver samples of two gadoid species, Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus), sampled in the southern Barents Sea in the period 1992-2015, were studied for the levels of six types of persistent organic pollutants (POPs): polychlorinated biphenyls (PCBs), chlorinated organic pesticides (DDTs, hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), trans-nonachlor (TNC)), and polybrominated diphenyl ethers (PBDEs). Higher average levels were found in cod than in haddock. Sampling approximately every third year allowed studies of temporal trends for all the compound groups except PBDEs. Time series are reported for 1992-2015 for Atlantic cod and for 1998-2015 for haddock. Decreasing temporal trends have been modeled in cod for the analyzed POPs for this time period. The decrease seems to be slowing down in the later years. HCB levels showed least decrease with time among all the contaminants, with the poorest fit to the proposed model. Similar time trends were found in haddock, but the decrease is less apparent due to shorter time series. The observed time trends of legacy POPs document the effectiveness of efforts during the 1990s to reduce the levels of these contaminants in the marine environment but question the possibility to eliminate them altogether from the marine environment in the foreseeable future.

Contaminants of emerging concern in freshwater fish from four Spanish Rivers

This study investigated the occurrence of 135 contaminants of emerging concern (CECs) - pharmaceuticals, pesticides, a set of endocrine disrupting compounds (EDCs) (parabens, bisphenols, hormones, triazoles, organophosphorus flame retardants and triclosan), UV-filters, perfluoroalkyl substances (PFASs) and halogenated flame retardants (HFRs) - in 59 fish samples, collected in 2010 in 4 Spanish Rivers (Guadalquivir, Júcar, Ebro and Llobregat). Of the 135 CECs, 76 including 8 pharmaceuticals, 25 pesticides, 10 EDCs, 5 UV-filters, 15 PFASs and 13 HFRs were detected. Pharmaceuticals were the less frequently found and at lower concentrations. Pesticides, EDCs, UV-filters, PFASs and HFRs were detected more frequently (>50% of the samples). The maximum concentrations were 15 ng/g dry weight (dw) for pharmaceuticals (diclofenac), 840 ng/g dw for pesticides (chlorpyrifos), 224 ng/g dw for EDCs (bisphenol A), 242 ng/g dw for UV-filters (EHMC), 1738 ng/g dw for PFASs (PFHxA) and 64 ng/g dw for HFRs (Dec 602). The contaminants detected in fish are commonly detected also in sediments. In light of current knowledge, the risk assessment revealed that there was no risk for humans related to the exposure to CECs via freshwater fish consumption. However, results provide detailed information on the mixtures of CECs accumulated that would be very useful to identify their effects on aquatic biota.

Levels of regulated POPs in fish samples from the Sava River Basin. Comparison to legislated quality standard values

Fish samples of different species (i.e. rainbow trout (Onchorhynchus mykiss), barbel (Barbus barbus) and European chub (Squalius cephalus)) were collected from the Sava River Basin for a preliminary investigation of the levels of PCDD/Fs, PCBs, PBDEs and PFAS as a whole. Concentrations of PCDD/Fs, in terms of pg WHO-TEQ/g ww, were below the maximum limit established at the Commission Regulation (EU) No 1259/2011. On the contrary, when DL-PCBs were also included, levels increase up to 11.7 pg WHO-TEQ_{PCDD/Fs+DL-PCBs}/g ww in a particular case, with two samples out of a total of ten exceeding the maximum set at this EU Regulation and the EQS established at the European Directive regarding priority substances in the field of water policy (0.0065 ng WHO-TEQ_{PCDD/Fs+DL-PCBs}/g ww). A similar trend was also observed for NDL-PCBs, whit the same two samples, from the lower stretch of the river basin, exceeding the maximum limit allowed at the EU Regulation (125 ng/g ww). For PBDEs, levels found in all the samples exceeded the EQS (0.0085 ng/g ww) up to more than a thousand times and 40% of the samples presented PFOS values above the EQS. Data from this study were compared to values reported at the literature for fish from other geographical areas.

Persistent organic pollutants in fish from Charleston Harbor and tributaries, South Carolina, United States: A risk assessment

Fish consumption is an important route of exposure to persistent organic pollutants (POPs) in dolphins as well as humans. In order to assess the potential risks associated with these contaminants, 39 whole fish and 37 fillets from fish representing species consumed by dolphins and humans captured from Charleston Harbor and tributaries, South Carolina, USA, were measured for a suite of POPs. Polychlorinated biphenyls (PCBs) were the predominant contaminant with concentrations ranging from 5.02 to 232.20 ng/g in whole fish and 5.42-131.95 ng/g in fillets (weight weight ww) followed by total organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs). Total POPs levels varied by location and species with general trends indicating significantly higher levels in fish from the Cooper (93.4 ng/g ww) and Ashley Rivers (56.2 ng/g ww) compared to Charleston Harbor (31.6 ng/g ww). Mullet and spot were found to have significantly higher PCBs, OCPs and total POPs, 2-3 times higher than red drum; mullet were also significantly higher in OCPs compared to seatrout. PCB concentrations in whole fish and fillets exceeded EPA human screening values for cancer risk in all fish sampled. For PCBs in fillets, all samples had values of maximum allowable meals per month that were less than the EPA, FDA guidelines for recommended fish meals per month, suggesting lower (more stringent) allowable fish meals per month. All fish exceeded PBDE wildlife values and all fish except two exceeded the level where 95% of the dolphin population would have tissue levels below the health effect threshold. Considering that POP concentrations in fish potentially consumed by humans exceed human health effect thresholds levels, consumption advisories should be considered as a prudent public health measure.

Deriving aquatic life criteria for PBDEs in China and comparison of species sensitivity distribution with TBBPA and HBCD

Polybrominated diphenyl ethers (PBDEs) are important industrial brominated flame retardants. PBDEs have raised great concerns for their persistence, bioaccumulation, and harm to aquatic life and human health. Pentabromodiphenyl ether (PeBDE), octabromodiphenyl ether (OcBDE), and decabromodiphenyl ether (DeBDE) are three main commercial PBDEs congeners. In this study, published ecotoxicity data of these three PBDEs congeners for Chinese freshwater species were collected, and several acute and chronic toxicity tests for the three PBDEs congeners were performed. Using the derivation method for aquatic life criteria developed by the United States Environmental Protection Agency (USEPA), we determined that the criterion maximum concentration (CMC) for PeBDE, OcBDE and DeBDE for protection of freshwater organisms were 0.0492 mg/L, 0.197 mg/L and 0.239 mg/L, respectively. The criterion continuous concentration (CCC) for PeBDE, OcBDE and DeBDE were 0.0103 mg/L, 0.0224 mg/L and 0.0267 mg/L, respectively. The results provided a good reference for the derivation of PBDEs' water quality criteria and a basis for ecological risk assessment of PBDEs. In addition, the results of species sensitivity distribution comparison showed that the toxicity rank of five brominated flame retardants was TBBPA > PeBDE > OcBDE > DeBDE > HBCD.

Stereoisomer-Specific Trophodynamics of the Chiral Brominated Flame Retardants HBCD and TBECH in a Marine Food Web, with Implications for Human Exposure

Stereoisomers of 1,2,5,6,9,10-hexabromocyclododecane (HBCD) and 1,2-dibromo-4-(1,2-dibromoethyl)-cyclohexane (TBECH) were determined in sediments and 30 marine species in a marine food web to investigate their trophic transfer. Lipid content was found to affect the bioaccumulation of ΣHBCD and ΣTBECH in these species. Elevated biomagnification of each diastereomer from prey species to marine mammals was observed. For HBCD, biota samples showed a shift from γ- to α-HBCD when compared with sediments and technical mixtures; trophic magnification potential of (-)-α- and (+)-α-HBCD were observed in the food web, with trophic magnification factors (TMFs) of 11.8 and 8.7, respectively. For TBECH, the relative abundance of γ- and δ-TBECH exhibited an increasing trend from abiotic matrices to biota samples; trophic magnification was observed for each diastereomer, with TMFs ranging from 1.9 to 3.5. The enantioselective bioaccumulation of the first eluting enantiomer of δ-TBECH in organisms at higher TLs was consistently observed across samples. This is the first report on the trophic transfer of TBECH in the food web. The estimated daily intake of HBCD for Hong Kong residents was approximately 16-times higher than that for the general population in China, and the health risk to local children was high, based on the relevant available reference dose.