Brominated flame retardants and seafood safety: a review

Influence of paternal factors on plastic ingestion and brominated chemical exposure in East Tropical Atlantic Procellariid chicks

The presence of plastic debris and organo-brominated compounds in the marine environment poses a concern to wildlife. Plastic can absorb and release chemical compounds, making their ingestion potentially harmful, while chemical compounds have become omnipresent, with a tendency to bioaccumulate in the food web. Seabirds are often used as indicators of marine plastic pollution, yet studies on the exposure of tropical communities to plastic contamination are still scarce. In this study we monitored the amounts of plastics in faeces and organo-brominated compounds ingested/assimilated in feathers by adults and chicks of Cape Verde shearwaters and Bulwer's petrels from Cabo Verde. Anthropogenic pollutants, polybrominated diphenyl ethers (PBDEs), and naturally generated methoxylated-PBDEs (MeO-PBDEs) were among the probed compounds. The frequency of plastic debris ingestion was similar in both species' adults and chicks, although, the characteristics of the ingested plastic differed. Frequency and number of microplastics increased throughout the nestling season for chicks from both species. All species and age groups showed the presence of PBDEs and MeO-PBDEs. Among PBDEs, Bulwer's petrels exhibited higher concentrations than Cape Verde shearwaters, and chicks had higher concentration profiles than adults. Specifically, Bulwer's petrel chicks showed higher concentrations than Cape Verde shearwater chicks. On the contrary, Cape Verde shearwater adults exhibited higher occurrence and concentrations of MeO-PBDEs when compared to Cape Verde shearwater chicks. We found no effect of plastic loadings or loadings of organohalogen contaminants on body condition or size, although harmful effects may be hidden or reveal themselves in a medium- to long-term. Feather samples from both adults and chicks were shown to be useful for comparing intraspecific contamination levels and appear suitable for the long-term assessment of organohalogen contaminants in seabirds. Species-specific foraging and feeding strategies are likely the drivers of the observed variation in organochlorine contamination burdens among seabird species.

Kelp forest food webs as hot spots for the accumulation of microplastic and polybrominated diphenyl ether pollutants

Kelp forests (KFs) are one of the most significant marine ecosystems in the planet. They serve as a refuge for a wide variety of marine species of ecological and economic importance. Additionally, they aid with carbon sequestration, safeguard the coastline, and maintain water quality. Microplastic (MP) and polybrominated diphenyl ethers (PBDEs) concentrations were analyzed across trophic levels in KFs around Todos Santos Bay. Spatial variation patterns were compared at three sites in 2021 and temporal change at Todos Santos Island (TSI) in 2021 and 2022. We analyzed these MPs and PBDEs in water, primary producers (Macrocystis pyrifera), grazers (Strongylocentrotus purpuratus), predators (Semicossyphus pulcher), and kelp detritus. MPs were identified in all samples (11 synthetic and 1 semisynthetic polymer) and confirmed using Fourier-transform infrared microspectroscopy-attenuated total reflectance (μ-FTIR-ATR). The most abundant type of MP is polyester fibers. Statistically significant variations in MP concentration were found only in kelps, with the greatest average concentrations in medium-depth kelps from TSI in 2022 (0.73 ± 0.58 MP g-1 ww) and in the kelp detritus from TSI in 2021 (0.96 ± 0.64 MP g-1 ww). Similarly, PBDEs were found in all samples, with the largest concentration found in sea urchins from Punta San Miguel (0.93 ± 0.24 ng g-1 ww). The similarity of the polymers can indicate a trophic transfer of MPs. This study shows the extensive presence of MP and PBDE subtropical trophic web of a KF, but correlating these compounds in environmental samples is highly complex, influenced by numerous factors that could affect their presence and behavior. However, this suggests that there is a potential risk to the systems and the services that KFs offer.

Low concentrations of tetrabromobisphenol A promote the biofilm formation of methicillin-resistant Staphylococcus aureus

The effect and underlying mechanism of tetrabromobisphenol A (TBBPA), a plastic additive, on biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA USA300) remain unknown. This study first investigated the impact of different concentrations of TBBPA on the growth and biofilm formation of USA300. The results indicated that a low concentration (0.5 mg/L) of TBBPA promoted the growth and biofilm formation of USA300, whereas high concentrations (5 mg/L and 10 mg/L) of TBBPA had inhibitory effects. Further exploration revealed that the low concentration of TBBPA enhance biofilm formation by promoting the synthesis of extracellular proteins, release of extracellular DNA (eDNA), and production of staphyloxanthin. RTqPCR analysis demonstrated that the low concentration of TBBPA upregulated genes associated with extracellular protein synthesis (sarA, fnbA, fnbB, aur) and eDNA formation (atlA) and increased the expression of genes involved in staphyloxanthin biosynthesis (crtM), suggesting a potential mechanism for enhanced resistance of USA300 to adverse conditions. These findings shed light on how low concentrations of TBBPA facilitate biofilm formation in USA300 and highlight the indirect impact of plastic additives on pathogenic bacteria in terms of human health. In the future, in-depth studies about effects of plastic additives on pathogenicity of pathogenic bacteria should be conducted. CAPSULE: The protein and eDNA contents in biofilms of methicillin-resistant Staphylococcus aureus are increased by low concentrations of TBBPA.

The emerging and legacy persistent organic contaminants in corals of the South China Sea

Seawater warming, ocean acidification and chemical pollution are the main threats to coral growth and even survival. The legacy persistent organic contaminants (POCs), such as polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), and the emerging contaminants, including polybrominated diphenyl ethers (PBDEs), dechlorane plus (DPs) and novel brominated flame retardants (NBFRs) were studied in corals from Luhuitou fringing reef in Sanya Bay and Yongle atoll in Xisha Islands, the South China Sea (SCS). Total average concentrations of ∑16PAHs, ∑23OCPs, ∑34PCBs, ∑8PBDEs, ∑2DPs and ∑5NBFRs in 20 coral species (43 samples) from the SCS were 40.7 ± 34.6, 5.20 ± 5.10, 0.197 ± 0.159, 3.30 ± 3.70, 0.041 ± 0.042 and 36.4 ± 112 ng g-1 dw, respectively. PAHs and NBFRs were the most abundant compounds and they are likely to be dangerous pollutants for future coral growth. Compared to those found in other coral reef regions, these pollutants concentrations in corals were at low to median levels. Except for PBDEs, POCs in massive Porites were significantly higher than those in branch Acropora and Pocillopora (p < 0.01), as large, closely packed corals may be beneficial for retaining more pollutant. The current study contributes valuable data on POCs, particularly for halogenated flame retardants (HFRs, including PBDEs, DPs and NBFRs), in corals from the SCS, and will improve our knowledge of the occurrence and fate of these pollutants in coral reef ecosystems.

Microplastics ingestion and endocrine disrupting chemicals (EDCs) by breeding seabirds in the east tropical Atlantic: Associations with trophic and foraging proxies (δ15N and δ13C)

In this study we found that endocrine disrupting chemicals (EDCs) were omnipresent in a tropical seabird community comprising diverse ecological guilds and distinct foraging and trophic preferences. Because EDCs tend to bioaccumulate within the food web and microplastics can absorb and release harmful chemical compounds, our findings draw attention to the potential threats to wildlife. Thus, the goal of this study was to investigate the role of plastic ingestion, trophic and foraging patterns (δ15N and δ13C) of five tropical seabird species breeding in sympatry, on the exposure to EDCs, namely Polybrominated diphenyl ethers (PBDEs), methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and personal care products (PCPs, e.g., musk fragrances and UV-filters). Results indicated that microplastics occurrence and EDCs detection frequency varied among species. Microplastics occurrence was higher in species with dual and coastal foraging strategies. Preen oil had higher levels of MeO-PBDEs and PCPs, while serum had higher levels of PBDEs. In brown boobies, the correlation between microplastics and ∑PBDEs levels was significant, suggesting that microplastics ingestion is a key PBDEs route. Trophic position (δ15N) plays a key role in PBDEs accumulation, particularly in Bulwer's petrel, which occupies a high trophic position and had more specialized feeding ecology than the other species. MeO-PBDEs were linked to foraging habitat (δ13C), although the link to foraging locations deserves further investigation. Overall, our findings not only fill key gaps in our understanding of seabirds' exposure to microplastics and EDCs, but also provide an essential baseline for future research and monitoring efforts. These findings have broader implications for the marine wildlife conservation and pollution management in sensitive environments, such as the tropical regions off West Africa.

Toxic Effects and Mechanisms of Polybrominated Diphenyl Ethers

Polybrominated diphenyl ethers (PBDEs) are a group of flame retardants used in plastics, textiles, polyurethane foam, and other materials. They contain two halogenated aromatic rings bonded by an ester bond and are classified according to the number and position of bromine atoms. Due to their widespread use, PBDEs have been detected in soil, air, water, dust, and animal tissues. Besides, PBDEs have been found in various tissues, including liver, kidney, adipose, brain, breast milk and plasma. The continued accumulation of PBDEs has raised concerns about their potential toxicity, including hepatotoxicity, kidney toxicity, gut toxicity, thyroid toxicity, embryotoxicity, reproductive toxicity, neurotoxicity, and immunotoxicity. Previous studies have suggested that there may be various mechanisms contributing to PBDEs toxicity. The present study aimed to outline PBDEs' toxic effects and mechanisms on different organ systems. Given PBDEs' bioaccumulation and adverse impacts on human health and other living organisms, we summarize PBDEs' effects and potential toxicity mechanisms and tend to broaden the horizons to facilitate the design of new prevention strategies for PBDEs-induced toxicity.

Combined effects of climate change and BDE-209 dietary exposure on the behavioural response of the white seabream, Diplodus sargus

Decabromodiphenyl-ether (BDE-209) is a persistent organic pollutant ubiquitously found in marine environments worldwide. Even though this emerging chemical contaminant is described as highly toxic, bioaccumulative and biomagnifiable, limited studies have addressed the ecotoxicological implications associated with its exposure in non-target marine organisms, particularly from a behavioural standpoint. Alongside, seawater acidification and warming have been intensifying their impacts on marine ecosystems over the years, compromising species welfare and survival. BDE-209 exposure as well as seawater acidification and warming are known to affect fish behaviour, but information regarding their interactive effects is not available. In this study, long-term effects of BDE-209 contamination, seawater acidification and warming were studied on different behavioural traits of Diplodus sargus juveniles. Our results showed that D. sargus exhibited a marked sensitivity in all the behaviour responses after dietary exposure to BDE-209. Fish exposed to BDE-209 alone revealed lower awareness of a risky situation, increased activity, less time spent within the shoal, and reversed lateralization when compared to fish from the Control treatment. However, when acidification and/or warming were added to the equation, behavioural patterns were overall altered. Fish exposed to acidification alone exhibited increased anxiety, being less active, spending more time within the shoal, while presenting a reversed lateralization. Finally, fish exposed to warming alone were more anxious and spent more time within the shoal compared to those of the Control treatment. These novel findings not only confirm the neurotoxicological attributes of brominated flame retardants (like BDE-209), but also highlight the relevance of accounting for the effects of abiotic variables (e.g. pH and seawater temperature) when investigating the impacts of environmental contaminants on marine life.

Seasonal occurrence and risk assessment of endocrine-disrupting compounds in Tagus estuary biota (NE Atlantic Ocean coast)

Estuaries are continually threatened by anthropogenic pressures, consequently, a large group of contaminants harmful to human health affects the aquatic biota; therefore, it is necessary to monitor their quality. This study deals with the determination of a large group of compounds representing different endocrine-disrupting compounds (EDCs) classes [21 pesticides, 4 polycyclic musk fragrances, 4 UV-filters, 7 bisphenols, 6 polybrominated diphenyl ethers (PBDEs) and 8 of their methoxylated (MeO-BDEs)] in several estuarine species (fish, bivalves, crustaceans, earthworm, and macroalgae) collected seasonally along one year in two distinct areas of Tagus River estuary ("contaminated" vs. "clean" areas). The most abundant compounds found were galaxolide (HHCB) (81% positive samples; 0.04-74 ng/g ww), isoamyl 4-methoxycinnamate (IMC) (64%; 1.13-251 ng/g ww), alachlor (44%; 0.08-16 ng/g ww), and BDE-47 (36%; 0.06-2.26 ng/g ww). Polycyclic musks were the most frequent contaminants in fish (seabass, barbus, mullet, and sole) and macroalgae samples, while UV-filters were predominant in bivalves and crustaceans, and bisphenols in earthworms. Seasonal variation was verified for Σpesticides and Σmusks, with significantly higher levels in summer and autumn, whereas ΣUV-filters highest levels were found in spring and summer, and for ΣPBDEs statistically higher levels were registered in cold seasons (autumn and winter). Σbisphenols were significantly lower in spring than in the other seasons. In general, considering all species analysed in both areas, no statistically significant differences (p > 0.05) were verified between the two collection areas. Based on the estimated daily intake data, consumption of fish from this estuary is unlikely to be a human health concern, since the levels of contamination were below the toxicological threshold values. Overall, the data obtained in this study will allow regulatory authorities to identify and prioritize contaminants monitoring programs in estuaries, such as the case of bisphenol A, which was found, for the first time, in earthworm and clam species.

In situ detection of the genotoxic potential as one of the lines of evidence in the weight-of-evidence approach-the Joint Danube Survey 4 Case Study

Environmental studies which aim to assess the ecological impact of chemical and other types of pollution should employ a complex weight-of-evidence approach with multiple lines of evidence (LoEs). This study focused on in situ genotoxicological methods such as the comet and micronucleus assays and randomly amplified polymorphic DNA analysis as one of the multiple LoEs (LoE3) on the fish species Alburnus alburnus (bleak) as a bioindicator. The study was carried out within the Joint Danube Survey 4 (JDS4) at nine sites in the Danube River Basin in the Republic of Serbia. Out of nine sampling sites, two were situated at the Tisa, Sava, and Velika Morava rivers, and three sites were at the Danube River. The three additionally employed LoEs were: SumTUwater calculated based on the monitoring data in the database of the Serbian Environmental Protection Agency (SEPA) (LoE1); in vitro analyses of JDS4 water extracts employing genotoxicological methods (LoE2); assessment of the ecological status/potential by SEPA and indication of the ecological status for the sites performed within the JDS4 (LoE4). The analyzed biomarker responses in the bleak were integrated into the unique integrated biomarker response index which was used to rank the sites. The highest pollution pressure was recorded at JDS4 39 and JDS4 36, while the lowest was at JDS4 35. The impact of pollution was confirmed at three sites, JDS4 33, 40, and 41, by all four LoEs. At other sampling sites, a difference was observed regarding the pollution depending on the employed LoEs. This indicates the importance of implementing a comprehensive weight-of-evidence approach to ensure the impact of pollution is not overlooked when using only one LoE as is often the case in environmental studies.

Concentration, Distribution and Biomagnification of Novel Brominated Flame Retardant in Grassland Food Chain and Sheep from Inner Mongolia, China

Novel brominated flame retardants (NBFRs) have been of great concern in the past few years due to their ubiquity in the environment and potential bioconcentration characteristics. This study takes Xilingol grassland in Inner Mongolia as the research area to analyze the pollution characteristics of NBFRs (pTBX, HBB, PBT, PBBz, and PBEB) in the grassland food chain. pTBX was more likely to be biomagnified in the food chain of amphibians, reptiles, and birds, whereas PBT and HBB were more likely to be biomagnified in the food chain of mammals. This may be because these animals have different diets and metabolic patterns. According to the concentration distribution of NBFRs in sheep organs and tissues, PBT, HBB, and PBBz easy bioaccumulated in sheep. The biomagnification effect of sheep adipose tissue and internal organs on NBFRs was inconsistent, so the biomagnification of chemicals in organisms cannot be determined only by the biomagnification of adipose tissue.

Microplastics boost the accumulation of tetrabromobisphenol A in a commercial clam and elevate corresponding food safety risks

Marine bivalve molluscs are one of the primary seafood for consumers. Inhabiting terrigenous pollutant-convergent coastal areas and feeding through seawater filtration, edible bivalves are subjected to waterborne emerging pollutants such as microplastics (MPs) and tetrabromobisphenol A (TBBPA). Nevertheless, the potential risks of consuming MP-TBBPA contaminated seafood are still largely unknown. With that, accumulation of TBBPA with and without the presence of MPs in a commercial bivalve species, blood clam (Tegillarca granosa), was determined in the present study. Meanwhile, corresponding target hazard quotients (THQs) as well as margins of exposure (MoEs) were estimated to evaluate the potential health risks for clam consumers. Furthermore, the impacts of pollutants accumulation on the detoxification process and energy supply were analysed. The data obtained demonstrated that MPs aggravate the accumulation of TBBPA in clams, leading to elevated potential food safety risks (indicated by higher THQ values and lower MoE values) for consumers. In addition, the in vivo contents of CYP1A1 and UDP-glucuronosyltransferase, the enzymatic activity of glutathione-S-transferase, and the expression levels of five detoxification-related genes were all dramatically suppressed by MP-TBBPA. Furthermore, clams exposed to MP-TBBPA had significantly lower adenosine triphosphate contents and lower pyruvate kinase and phosphofructokinase activities. These results indicated that the aggravation of TBBPA accumulation may be due to the hence disruption of detoxification process and limited energy available for detoxification.

Phototransformation of tetrabromobisphenol A in saline water under simulated sunlight irradiation

The widespread use of halogenated flame retardants in recent years has led to the accumulation of TBBPA in water, which may cause potential harm to living organisms. The phototransformation of the flame retardant TBBPA in alkaline saline water under simulated sunlight irradiation was investigated. The effects of abiotic factors such as the initial concentration of TBBPA, chloride ion concentration, solution pH, inorganic anions and cations, dissolved organic matter (DOM) were studied. The results showed that the phototransformation rate of TBBPA accelerated with the decrease of the initial concentration of TBBPA, the increase of chloride ion concentration and solution pH. The scavenging experiments showed that •OH, ¹O₂, O₂•^- and ³TBBPA* all participated in the phototransformation of TBBPA. The presence of NO₃^-, CO₃^2-, SO₄^2-, Mg²⁺, Ca²⁺, Fe³⁺ and fulvic acid (FA) all inhibited the phototransformation of TBBPA in the present study. The phototransformation products of TBBPA were detected by liquid chromatography-mass spectrometry (LC-MS), and the phototransformation pathways were proposed. This is the first report on the photo-induced generation of halogen exchange products from TBBPA in saline solutions, which will contribute to a better understanding of the environmental behavior and risks of BFRs in water.

Bromine in chicken eggs, feed, and water from different regions of Ukraine

The purpose of these studies was to analyse and compare the content of bromine in samples of chicken eggs, feed, and water from different regions of Ukraine in the dynamics of 2016 – 2020: with an increased risk of bromine in products (Kharkiv, Poltava, Dnipropetrovsk and Mykolaiv regions) and outside the risk zone (Volyn, Vinnytsia and Zaporizhzhia). Studies of bromine content in eggs, feed, and water were performed in the laboratory of toxicological monitoring of the National Scientific Center "Institute of Experimental and Clinical Veterinary Medicine" (Kharkiv) using X-ray fluorescence analysis. As a result of the conducted researches, the increase of the bromine content in chicken eggs in the dynamics of 2016 – 2020 was established: the bromine content increased regardless of the region of the poultry farm location. The highest bromine concentration in chicken eggs was found in Kharkiv, Dnipropetrovsk, Mykolaiv, and Zaporizhia regions. Bromine source in poultry products is the excessive intake of bromine in the poultry body with alimentary environmental factors (feed and water). Bromine content in feed for chickens increased in the research dynamics (from 35.1% in the Poltava region to 2.5 times in the Zaporizhzhia region). It exceeded the established EFSA (4.4% of the total) and the average in Ukraine (51.2% of the total number of samples). In addition, the average bromine content in feed from poultry farms of the studied regions of Ukraine correlated with the number of registered and approved bromine-containing pesticides. The average bromine concentration in water sources in the studied regions of Ukraine had no significant differences compared to the beginning of the study but exceeded the maximum allowable concentration by 21.7% in 2016, 34.8% in 2018 and 39.1% in 2020. The maximum bromine concentration was in water sources in Mykolayiv, Kharkiv, and Dnipropetrovsk regions.

A seafood risk tool for assessing and mitigating chemical and pathogen hazards in the aquaculture supply chain

Intricate links between aquatic animals and their environment expose them to chemical and pathogenic hazards, which can disrupt seafood supply. Here we outline a risk schema for assessing potential impacts of chemical and microbial hazards on discrete subsectors of aquaculture-and control measures that may protect supply. As national governments develop strategies to achieve volumetric expansion in seafood production from aquaculture to meet increasing demand, we propose an urgent need for simultaneous focus on controlling those hazards that limit its production, harvesting, processing, trade and safe consumption. Policies aligning national and international water quality control measures for minimizing interaction with, and impact of, hazards on seafood supply will be critical as consumers increasingly rely on the aquaculture sector to supply safe, nutritious and healthy diets.

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.

Polybrominated diphenyl ethers and their methoxylated congeners in Douro river estuary biota: Seasonal occurrence and risk assessment

Especially added on many industrial and domestic products as flame retardants (FRs), polybrominated diphenyl ethers (PBDEs) are among the chemicals of high environmental concern because of their potential harmfulness for environmental and human health. Seafood consumption is considered the main source of PBDEs and their methoxylated congeners (MeO-BDEs) for humans. The present study aims to investigate the seasonal occurrence of six PBDEs and eight MeO-BDEs congeners using Douro river biota (different trophic levels) as sentinels, as well as to evaluate the human exposure risk to PBDEs through seafood consumption. Biota samples (n = 273) were collected from one of the most important Portuguese estuaries in the north-western coast of Portugal at four different seasons (2019-2020). The analyses were performed by an environmental-friendly extraction procedure followed by Gas Chromatography coupled to a triple quadrupole detector (GC-MS/MS). PBDEs were detected in all seafood samples analysed, with means ranging from 0.02 ng g^-1 ww (flounder in autumn) to 3.75 ng g^-1 ww (mussel in winter). Levels of lower-brominated PBDE congeners were significantly higher than higher-brominated ones in all seasons (p < 0.01). MeO-BDEs ranged from 0.001 ng g^-1 ww (grey mullet in summer) to 5.66 ng g^-1 ww (green crab in spring). Crabs and mussels presented the highest means of PBDEs and MeO-BDEs. Regarding the health risk assessment of the studied PBDE congeners (47, 99, and 153), consumption of Douro river fish is not a case of concern for consumers.

Health toxicity effects of brominated flame retardants: From environmental to human exposure

Hexabromocyclododecane (HBCD) and Tetrabromobisphenol A (TBBP-A) are brominated flame retardants widely used in variety of industrial and consumer products (e.g., automobiles, electronics, furniture, textiles and plastics) to reduce flammability. HBCD and TBBPA can also contaminate the environment, mainly water, dust, air and soil, from which human exposure occurs. This constant exposure has raised some concerns against human health. These compounds can act as endocrine disruptors, a property that gives them the ability to interfere with hormonal function and quantity, when HBCD and TBBPA bind target tissues in the body. Studies in human and animals suggest a correlation between HBCD and TBBPA exposure and adverse health outcomes, namely thyroid disorders, neurobehavior and development disorders, reproductive health, immunological, oncological and cardiovascular diseases. However, in humans these effects are still poorly understood, once only a few data evaluated the human health effects. Thus, the purpose of this review is to present the toxicity effects of HBCD and TBBPA and how these compounds affect the environment and health, resorting to data and knowledge of 255 published papers from 1979 to 2020.

Determination of low-density polyethylene-water partition coefficients for novel halogenated flame retardants with the large volume model and co-solvent model

The partition coefficient (K_pew) of an analyte between low-density polyethylene (LDPE) film and water is a critical parameter for measuring freely dissolved concentrations of the analyte with PE passive sampling devices. Measuring log K_pew for super hydrophobic organic chemicals (HOCs) have been proven extremely difficult. The present study developed a large volume model for measuring log K_pew of super HOCs, i.e., novel halogenated flame retardants (NHFRs). Results showed that the measured log K_pew values of selected PAHs and PCBs obtained by the large volume model were in line with those from the co-solvent model and the literature data within less 0.3 log units of difference, while those of NHFRs (6.27-7.34) except for hexachlorocyclopentadienyldibromocyclooctane (HCDBCO) and Decabromodiphenyl ethane (DBDPE) were significantly lower than those (6.51-8.89) from the co-solvent model. A curvilinear relationship was observed between log K_pew and log K_ow of all target compounds, with the turning point at log K_ow = ∼8.0 in the large volume model, but that was not found for the co-solvent model. These can be attributed to the large molecular volumes (> 450 Å³) for NHFRs, which require high Gibbs free energy to penetrate into the inside structures of LDPE in the large volume model. However, the solvent swelling effects in the co-solvent model needs to be investigated. Therefore, the large volume model is robust to determine the K_pew values of super HOCs for facilitating the application of aquatic passive sampling techniques.

ANN-Based Integrated Risk Ranking Approach: A Case Study of Contaminants of Emerging Concern of Fish and Seafood in Europe

Seafood, one of the most important food commodities consumed worldwide, is considered a high-quality, healthy, and safe food option. However, marine ecosystems are the ultimate destination for a large group of chemicals, including contaminants of emerging concern, and seafood consumption is a major pathway of human exposure. With growing awareness of food safety and food quality, and increased demand for information on the risk of contaminants of emerging concern, there is a need to assess food safety issues related to harmful contaminants in seafood and ensure the safety of marine food resources. In this study, the risks of emerging compounds (endocrine disruptors, brominated flame retardants, pharmaceuticals and personal care products, and toxic elements) in fish and seafood were analyzed according to their PBT (persistence, bioaccumulation, toxicity) properties as well as in terms of their concentration levels in seafood. A hazard index (HI) was estimated for each compound by applying an artificial neural network (ANN) approach known as Self-Organizing-Maps. Subsequently, an integrated risk rank (IRI) was developed considering the values of HI and the concentrations of emerging compounds in seafood species gathered from the scientific literature. Current results identified HHCB, MeHg, NP, AHTN and PBDE209 as the top five highest ranked compounds present in seafood, according to the 50th percentile (mean) of the IRI. However, this ranking slightly changed when taking into account the 99th percentile of the IRI, showing toxic elements, methylmercury and inorganic arsenic, as having the highest risk. The outcome of this study identified the priority contaminants and should help in regulatory decision-making and scientific panels to design screening programs as well as to take the appropriate safety measures.

Temporal trends of halogenated and organophosphate contaminants in striped dolphins from the Mediterranean Sea

PBDEs, HBCD, novel DBDPE, PBEB and HBB, dechloranes, OPFRs and natural MeO-PBDEs were monitored in muscle of striped dolphins (Stenella coeruleoalba) from the Mediterranean Sea collected in three time periods (1990, 2004-2009 and 2014-2018). PBDEs levels decreased about 60% in under three decades, from 5067 ± 2210 to 2068 ± 2642ngg^-1 lw, evidencing the success of their ban. Most PBDEs were found in all the samples, with BDE-47, -99, -154, -100 and -153 as the main contributors. Found in 71.4% of the samples, α-HBCD was stable through time and usually <LOQ. DBDPE concentrations decreased by 89% from 1990 to 2004-2009 and have remained stable since. HBB occurred rarely and decreased by 94% to a current few ngg^-1 lw. Dec 602 was the main dechlorane with stable concentrations around 1200 ngg^-1 lw, but a declining trend might have started in the last years. OPFRs concentrations were stable and showed the highest concentrations of all FRs in 2014-2018: 6253 ± 11,293ngg^-1 lw. TBOEP and TNBP contributed to most of the OPFR concentration, the former with decreasing levels by 96%. MeO-PBDEs showed mean concentrations between 600 and 700ngg^-1 lw in all periods. Non-targeted analysis allowed the identification and semi-quantification of additional chlorinated pollutants, such as polychlorinated terphenyls (PCTs) (levels decreasing by 81% to a current 770 ngg^-1 lw mean) and polychlorinated diphenyl ethers (PCDEs) (decreasing by 83% to a current 3200ngg^-1 lw) in Mediterranean marine mammals for the first time.

Determinants of flame retardants in non-occupationally exposed individuals - A review

Flame retardants (FRs) constitute a large group of different substances, some of which have been phased out of the market due to health concerns, while others are still used in many common consumer products to prevent fire hazards. This review addressed the determinants of FRs in non-occupationally exposed individuals based on surveys and questionnaire data. For this literature review, three databases (Scopus, Pubmed and Web of Knowledge) were searched by applying suitable terms, inclusion and exclusion criteria, producing a final selection of 78 articles for review. Based on these surveys there is epidemiological evidence for a significant association (p < 0.05) among human exposure and demographic factors, as well as a significant correlation between exposure to FRs and behavioural and environmental factors. Age, gender, housing characteristics, electrical and electronic equipment and mouthing behaviour (in children) play a leading role in human exposure to FRs as published studies demonstrated. However, the methodological differences among studies such as population size, questionnaire design and statistical analysis did not reveal a complete pattern of human exposure routes. Risk perception and communication are also discussed based on limited available data. Knowledge gaps and future perspectives relating to standardized protocols, elucidation of contamination sources, and risk response of health information from different target groups were also identified.

Novel brominated flame retardants - A review of their occurrence in indoor air, dust, consumer goods and food

This critical review summarizes the occurrence of 63 novel brominated flame retardants (NBFRs) in indoor air, dust, consumer goods and food. It includes their EU registration and (potential) risks. The increasing application of NBFRs calls for more research on their occurrence, environmental fate and toxicity. This review reports which NBFRs are actually being studied, which are detected and which are of most concern. It also connects data from the European Chemical Association on NBFRs with other scientific information. Large knowledge gaps emerged for 28 (out of 63) NBFRs, which were not included in any monitoring programs or other studies. This also indicates the need for optimized analytical methods including all NBFRs. Further research on indoor environments, emission sources and potential leaching is also necessary. High concentrations of 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EH-TBB), bis(2-ethylhexyl)tetrabromophthalate (BEH-TEBP), decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) were often reported. The detection of hexabromobenzene (HBB), pentabromotoluene (PBT), 1,4-dimethyltetrabromobenzene (TBX), 4-(1,2-dibromoethyl)-1,2-dibromocyclohexane (DBE-DBCH) and tetrabromobisphenol A bis(2,3-dibromopropyl) ether (TBBPA-BDBPE) also raises concern.

Bioaccessibility of polybrominated diphenyl ethers and their methoxylated metabolites in cooked seafood after using a multi-compartment in vitro digestion model

Polybrominated diphenyl ethers (PBDEs) comprise a major class of brominated flame retardants and are well-known endocrine disruptors. The dietary route, through contaminated seafood consumption, is a main contributor to human exposure. Hence, the aim of this work was to provide thorough information on the dietary pathway of PBDEs and their methoxylated metabolites (MeO-PBDEs) after consumption of contaminated cooked seafood. The analyses were performed by gas chromatography (tandem) mass spectrometry using environmental-friendly extractive methods validated for fish and samples from several digestion segments with limits of detection at the pictogram level (per gram or milliliter of sample). Selected fish species were artificially contaminated and cooked using common household practices (steamed, grilled and microwaved), resulting in considerable loss of pollutants (up to 32% loss), with significant differences between cooking methods and species. Finally, an in vitro method that simulates four human adult digestion steps (oral, gastric digestion, small and large intestinal digestion) was applied to raw and cooked fish. Bioaccessibility of PBDEs and MeO-PBDEs in small intestinal was low (below 24%), pointing to a heavy impact in gut microbiota. Nevertheless, gut microbiota was able to reduce the amounts of targeted contaminants (up to 82%) in the large intestine. The results achieved herein are of great value to predict both amounts and nature of PBDEs and MeO-PBDEs that seafood consumers may be exposed after the ingestion of contaminated food as to ascertain more accurately the impact on human and environmental health.

Enhanced adsorption of tetrabromobisphenol a (TBBPA) on cosmetic-derived plastic microbeads and combined effects on zebrafish

Microplastics (MPs) pollution and its potential environmental risks have drawn increasing concerns in recent years. Among which, microbeads in personal care and cosmetic products has becoming an emerging issue for their abundance as well as the knowledge gaps in their precise environmental behaviors in freshwater. The present study investigated the sorption process of tetrabromobisphenol A (TBBPA), the most widely applied and frequently encountered flame retardant in aquatic environments, on two sources of polyethylene (PE) particles (pristine PE particles and microbeads isolated from personal care and cosmetic products). Significantly enhanced adsorption capacity of microbeads was observed with up to 5-folds higher than the pristine PE particles. The sorption efficiency was also governed by solution pH, especially for the cosmetic-derived microbeads, indicating the strong adsorption of TBBPA on PE was dominated by both hydrophobic and electrostatic interactions. Additionally, combined effects on redox status of zebrafish were evaluated with two environmental relevant concentrations of PE particles (0.5 and 5 mg L^-1) using integrated biomarker response (IBR) index through a 14-d exposure. Co-exposure induced significant antioxidative stress than either PE or TBBPA alone when exposed to 0.5 mg L^-1 of MPs. After 7-d depuration, the IBR value for combination treatments [TBBPA + PE (L)] was 3-fold compared with that in MP-free groups, indicating the coexistence might exert a prolonged adverse effects on aquatic organisms. These results highlight the probability of risk from microbead pollution in freshwater, where toxic compounds can be adsorbed on microbeads in a considerable amount resulting in potential adverse effects towards aquatic organisms.

Effect of air pre-exposure on Tetrabromobisphenol A resistance in the clam Ruditapes philippinarum

The present study was conducted to evaluate how air pre-exposure influences the responses in gills and digestive gland of Ruditapes philippinarum on subsequent Tetrabromobisphenol A (TBBPA) exposure. Firstly, clams were maintained in seawater or pre-exposed to air for 24 h, and then exposed to 0 or 100 μg/L TBBPA. Clam tissues were sampled after 1 day (T1) and 7 days (T7) of exposure to TBBPA. The results showed that in comparison with TBBPA exposure alone, air pre-exposure following TBBPA exposure reduced TBBPA accumulation in both tissues, up-regulated mRNA levels of CAT, Hsp70 and pi-GST in gills, and induced GST activity and P-glycoprotein (Pgp) mRNA level in digestive gland of clams at T1, whereas increased lipid peroxidation at T7. Overall, the findings indicate that 24-h exposure to air can activate a priming mechanism withstanding the subsequent TBBPA exposure, which is transient and may change after prolonged subsequent exposure.

Multidisciplinary approach to determine the effect of polybrominated diphenyl ethers on gut microbiota

Environmental health is increasingly compromised by persistent toxic substances, which may have serious implications in food safety and, thus, in human health. Polybrominated diphenyl ethers (PBDEs) are anthropogenic contaminants with endocrine disruption abilities and are commonly found in seafood, the main route of human exposure. Growing evidence points out that the human gut microbiota interacts with xenobiotics, which may lead to impairment of host homeostasis if functions of microbiota become compromised. The aim of this study was to ascertain if the physiological balance of human gut microbiome is affected by the presence and degree of exposure to PBDEs. Fermentation was performed in a batch closed-system using an inoculum made from fresh human stool. The volatolomic profile was analysed by solid-phase microextraction coupled to gas chromatography-mass spectrometry. Mesophilic, Gram-negative bacteria and coliforms were quantified by classic plating methods. Changes in the gut microbiome were evaluated after DNA extraction followed by deep sequencing of the 16S rDNA region. The exposure to PBDEs resulted in an imbalance in sulfur, short-chain fatty acids and aromatic organic compounds, changing the microbial volatolome in a dose- and time-dependent manner. Slight deviations in the microbial structure of human gut occurred in the presence of PBDEs, especially for high doses of exposure. For the first time, the impact of PBDEs on the microbial homeostasis of human gut microbiota was taken into consideration, revealing noteworthy modifications with serious health implications even at oral exposure doses considered as safe by worldwide regulatory entities.

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.

Occurrence of legacy and emerging organic pollutants in whitemouth croakers from Southeastern Brazil

The whitemouth croaker (Micropogonias furnieri) is one of the most commercially important species along the Atlantic coast of South America. Moreover, some of its biological traits (long life span, inshore feeding, high trophic position) make this species a suitable sentinel of coastal pollution. Here, we investigated contamination by multiple legacy and emerging organic pollutants, such as brominated and chlorinated flame retardants, polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), in whitemouth croakers from two estuaries (Guanabara and Sepetiba Bays) located in industrialized and urbanized areas in Rio de Janeiro State, Southeastern Brazil. Furthermore, we assessed how biological and ecological features could explain the observed contamination patterns. Regarding brominated flame retardants, concentrations of polybrominated diphenyl ethers (PBDEs) varied from 7.6 to 879.7 pg g^-1 wet weight (w.w.), with high contribution of tetra-, penta-, hexa- and deca-BDEs. The sum of chlorinated flame retardants (dechlorane-related compounds, ΣDRC) ranged from <LOD to 41.1 pg g^-1 w.w., mostly represented by Dechlorane 603 and Dechlorane Plus (DP). Concentrations of PCDDs and PCDFs varied from <LOD to 1.7 pg g^-1 w.w., while the Toxic Equivalent (TEQ-PCDD/Fs) levels ranged from 0.1 to 0.2 pg g^-1 w.w. Positive correlations between δ¹⁵N and concentrations of tri-, tetra- and penta-BDEs, as well as ΣDRC, DP and anti-DP isomers suggested that ecological factors (namely biomagnification along the food web) influence contamination of whitemouth croakers in the estuaries studied. Moreover, the sum of PBDEs (ΣPBDE), tri- and tetra-BDEs concentrations were negatively correlated with fish size, suggesting that depuration by fishes and/or habitat shift throughout the whitemouth croaker's life cycle might also influence concentrations. Overall, our study emphasized the need for further investigations to help understand the complex patterns of bioaccumulation and biomagnification that seem to exist in Southeastern Brazil.

The effects of prosperity indices and land use indicators of an urban conurbation on the occurrence of hexabromocyclododecanes and tetrabromobisphenol A in surface soil in South China

Hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) are legacy brominated flame retardants which are still produced and used in China. In this study, 187 surface soils from the Pearl River Delta (PRD) urban conurbation in China were collected, and the effects of urban conurbation development on the concentrations, distributions and human exposure risk of HBCDs and TBBPA were investigated. The concentration ranges of Σ₃HBCD (sum of α-, β-, and γ-HBCD) and TBBPA in soil were below the limit of quantification (<LOQ) to 300 ng g^-1 dry weight (dw) and < LOQ to 53.1 ng g^-1 dw, respectively. Concentration levels of HBCDs and TBBPA in the PRD were affected both by distributions of land-use type and by the location of the city. Soils from residential areas contained the highest concentrations of Σ₃HBCD (median: 1.75 ng g^-1 dw) and TBBPA (1.92 ng g^-1 dw) among all land-use types. In addition, soils from the central PRD had higher Σ₃HBCD and TBBPA levels (0.46 and 0.90 ng g^-1 dw) than those from the surrounding areas (0.17 and 0.07 ng g^-1 dw). The concentrations of Σ₃HBCD and TBBPA were highly correlated with urbanization level, population density, regional GDP and per capita income in all cities studied (p < 0.01), which indicates that the prosperity of the urban conurbation may play an important role in soil contamination of HBCDs and TBBPA in the PRD. Children living in residential areas had the highest estimated daily intakes of Σ₃HBCD (7.09 pg kg^-1 d^-1) and TBBPA (7.76 pg kg^-1 d^-1), suggesting that people living in residential areas have a relatively higher exposure risk of HBCDs and TBBPA. This is a comprehensive study to report the effects of prosperity indices and land use indicators of an urban conurbation on the occurrence of HBCDs and TBBPA in soil in China.

Occurrence of hexabromocyclododecanes and tetrabromobisphenol A in fish and seafood from the sea of Sardinia - FAO 37.1.3 area: Their impact on human health within the European Union marine framework strategy directive

Levels of hexabromocyclododecane isomers α, β, γ, (HBCDDs) and tetrabromobisphenol A (TBBP-A) were determined in 24 representative samples of different wild fish and seafood species (benthic: N = 16; pelagic: N = 8) and 16 samples of farmed bivalve molluscs from the West Mediterranean Sea (FAO 37, 1.3 sub-area). An LC-MS/MS-based method with limits of quantification (LOQS) in the range of 0.01-0.05 ng g^-1 fresh weight (fw) was utilized. While α HBCDD was found in 80% of the 24 wild species samples, β and γ congeners were found in 33% and 25%, respectively. ΣHBCDD content ranged from 0.03 (Aristeus antennatus) to 0.68 (Sardina pilchardus) ng g^-1 fw as Upper Bound values across 2.00-4.46 trophic levels. In farmed molluscs, HBCDD congeners were always present and ranged from 0.22-0.52 ng g^-1 fw, with the exception of one farm (1.23-2.06 ng g^-1 fw), whose values suggest the presence of a regular emission source. TBBP-A levels always fell below the LOQ of 0.05 ng g^-1 fw in all samples. The results are in good agreement with results of previous studies from the Mediterranean Sea. The Environmental Quality Standard for human health from fish and seafood local consumption was set at 165 μg g^-1 fw. The Margin of Exposure of 490,020 as the ratio between the considered Health Based Guidance Level of 0.79 mg kg^-1 body weight and the geo-referenced HBCDD intake (P95 fish and seafood intake; mean ΣHBCDD contamination) indicates no threat to food safety.

Halogenated and organophosphorus flame retardants in cetaceans from the southwestern Indian Ocean

PBDEs, HBCD, DBDPE, PBEB and HBB, dechloranes and OPFRs, as well as natural MeO-PBDEs were monitored in muscle tissue of three dolphin species from the southwestern Indian Ocean (Delphinus delphis, Sousa plumbea and Tursiops aduncus) collected between 2012 and 2015. The mean PBDE concentration was 416 ± 333 ng g^-1 lw. BDE-47 was found in all samples and was almost half the total PBDE contamination. BDE-209, BDE-100 and BDE-99 were present in ≥85% of the samples. HBCD was detected in just two samples at 20 and 330 ng g^-1 lw. PBEB and HBB were not detected, while DBDPE was in all samples but always below its limit of quantification. Dec 602 was the only quantifiable dechlorane at 232 ± 549 ng g^-1 lw. Mean OPFR concentration was 10452 ± 11301 ng g^-1 lw. TBOEP was found in all samples making up most of the total OPFR contamination. MeO-PBDEs were detected in all samples at 114 ± 137 ng g^-1 lw. Data on flame retardants in biota and environmental samples from the southwestern Indian Ocean are scarce and, as a result, comparisons are difficult. However, data from other marine predators in the region, such as penguins, suggest that further studies are needed to determine if these concentrations are the consequence of a high local contamination or widespread thoughout the Indian Ocean.

Persistent and emerging pollutants assessment on aquaculture oysters (Crassostrea gigas) from NW Portuguese coast (Ria De Aveiro)

The study aim was to determine a range of relevant persistent and emerging pollutants in oysters produced in an aquaculture facility located in an important production area, to assure their safety for human consumption. Pollutants, including 16 PAHs, 3 butyltins (BTs), 29 flame retardants (FRs, including organophosphate and halogenated FRs), 35 pesticides (including 9 pyrethroid insecticides) and 13 personal care products (PCPs, including musks and UV filters), were determined in oysters' tissues collected during one year in four seasonal sampling surveys. The seasonal environmental pollution on the production site was evaluated by water and sediment analysis. Furthermore, oysters' nutritional quality was also assessed and related with the consumption of healthy seafood, showing that oysters are a rich source of protein with low fat content and with a high quality index all year around. Results showed that most analysed pollutants were not detected either in oyster tissues or in environmental matrixes (water and sediments). The few pollutants detected in oyster tissues, including both regulated and non-legislated pollutants, such as a few PAHs (fluorene, phenanthrene, anthracene, fluoranthene, pyrene and indenopyrene), FRs (TPPO, TDCPP, DCP, BDE-47, BDE-209 and Dec 602) and PCPs (galaxolide, galaxolidone, homosalate and octocrylene), were present at low levels (in the ng/g dw range) and did not represent a significant health risk to humans. The observed seasonal variations related to human activities (e.g. tourism in summer) highlights the need for environmental protection and sustainable resource exploration for safe seafood production.

Novel brominated flame retardant (NBFR) concentrations and spatial distributions in global fishmeal

Novel brominated flame retardants (NBFRs), which are lipophilic compounds that have been widely applied after the phasing-out of legacy BFRs, can bioaccumulate through the food chain. However, information on NBFRs in animal feeds, the beginning of farm-to-fork pathway, is very limited. Fishmeal is one of the most widely applied feedstuff worldwide. The present study identified eleven NBFRs from ninety-two globally collected fishmeal samples with levels in the range of 0.13-822 (mean: 15.1 ± 85.5) ng/g lipid weight (lw). Hexabromobenzene (HBB) and pentabromotoluene (PBT) were the most prevalent contributors (detection frequencies: 95.7% and 73.9%, respectively), and decabromodiphenylethane (DBDPE) was the weightiest contributor (accounted for 67.1% of the ΣNBFRs, mean: 12.1 ± 84.8 ng/g lw). From a geographical view, the highest NBFR level was found in Chinese fishmeal. The NBFRs fell within an order of magnitude in South America, Southeast Asia, Europe and United States. DBDPE was predominant in the fishmeal collected from China, South America and United States, but it was not detected in European fishmeal. The NBFR levels are significantly lower compared to the polybrominated diphenyl ethers (PBDEs) (p < 0.01), indicating that the distribution of NBFRs was not as wide as PBDEs in fishmeal. DBDPE was significantly correlated with BDE209 (r = 0.557, p < 0.01), which implies that the two chemicals might have similar sources. Quantitative structure-activity relationship (QSAR)results imply that the NBFRs might have similar persistence and biomagnification potential as legacy lipophilic POPs.

Species-dependent effects of earthworms on the fates and bioavailability of tetrabromobisphenol A and cadmium coexisted in soils

The activity of e-waste recycling often causes the combined pollution of tetrabromobisphenol A (TBBPA) and cadmium (Cd) in soils. In this study, the effects of their co-existence on each other's fate, further reflecting the bioavailability, were analyzed in the presence of two ecologically different earthworm species, endogeic Metaphire guillelmi and epigeic Eisenia fetida. Mineralization of ¹⁴C-TBBPA combined with 10 mg Cd kg^-1 was suppressed by the presence of M. guillelmi, whereas a facilitating effect was produced by the combination of 1 mg Cd kg^-1 in the soil-E. fetida system after a 14-day exposure. The uptake of ¹⁴C-TBBPA by M. guillelmi (17% of initial amount) and by E. fetida (10%) dominantly contributed to significant (P < 0.05) decrease of extractable (more bioavailable) ¹⁴C residues in soils both with and without Cd spiked, while the mineralization of ¹⁴C-TBBPA in the soils was negligible (<0.4%). Meanwhile the amendments of the two earthworm species exerted different impact on ¹⁴C distribution in bound residues. In general, co-exposure to Cd did not significantly (P > 0.05) influence the accumulation and metabolism of TBBPA in the earthworms. Both earthworms accumulated only ~7% of Cd in soil, however, the bioavailable Cd determined by the diffusive gradients in thin films technique declined by ~46% in the presence of M. guillelmi, and a much smaller decrease was determined in the presence of E. fetida. Amendment of TBBPA at environmental levels did not alter the accumulation and subcellular distribution of Cd in both earthworms unless that at high doses. The results highlighted the importance of considering the difference of the earthworm species and the interaction of pollutants in soil-risk assessments of such combined contamination. CAPSULE: M. guillelmi displayed greater effect on the fate of TBBPA and Cd co-existed in soils than E. fetida, while the accumulation, metabolism, or distribution of the two pollutants in earthworms did not significantly alter due to interactions between the two pollutants.

A nationwide survey of 31 organophosphate esters in sewage sludge from the United States

Organophosphate esters (OPEs) are used as flame retardants and plasticizers in a wide range of consumer products. Nevertheless, studies on the occurrence and inventory of OPEs in sewage sludge are limited. In this study, 20 OP triesters and 11 diesters were measured in 75 archived sewage sludge samples collected from 67 wastewater treatment plants (WWTPs) across the United States (US). The median concentrations of ∑20OP-triesters and ∑11OP-diesters in sludge were 1290 and 78.4 ng/g dry weight (dw), respectively. Sludge samples originating from the Western and Northeastern US contained higher concentrations of OP triesters than did those from the Midwestern and Southern US. Sludge samples from WWTPs with larger treatment capacity (>38 million liters per day) contained higher concentrations of OP diesters (p < 0.05). OP diesters in sludge originated from two sources, triester degradation and direct inputs. Land application of sludge to US soils was estimated to result in annual mass inputs of 12,400-14,900 kg/year of OP triesters and 663-796 kg/year of OP diesters. A hazard assessment was performed for 14 OPEs found in sludge, which suggested a low level of risk at the current land application practices of sludge.

Preliminary study of long-range transport of halogenated flame retardants using Antarctic marine mammals

Eight PBDE congeners, three emerging brominated flame retardants, five dechloranes and eight MeO-PBDEs were monitored in tissues (muscular, adipose, brain) and fur of southern elephant seal and Antarctic fur seal of the South Shetland Islands, Antarctic Peninsula. Total PBDEs and total dechloranes concentrations ranged between n.d.-6 ng/g lw. While PBDEs were not detected in brain tissue, Dec 602 was found in brain tissue of both seal species indicating that dechloranes -with potential neurological toxicity- could cross the blood-brain barrier. Emerging brominated flame retardants were not detected in any sample and only two MeO-PBDEs, which are of natural origin, were found. The presence of the detected compounds in biota from the Antarctic evidences their long-range transportation, being of special interest the detection of emerging compounds such as dechloranes. This is the first time that these contaminants have been detected in marine mammals from the Antarctic. BDE-47 concentrations were lower than previously reported for the same species, suggesting a successful effect of the existing regulation and bans on PBDEs. CAPSULE ABSTRACT: Halogenated flame retardants were in tissues of Antarctic seals proving long-range transport. Dechloranes showed similar behaviour to PBDEs, additionally they crossed the BBB.

Environmental Chemical Contaminants in Food: Review of a Global Problem

Contamination by chemicals from the environment is a major global food safety issue, posing a serious threat to human health. These chemicals belong to many groups, including metals/metalloids, polycyclic aromatic hydrocarbons (PAHs), persistent organic pollutants (POPs), perfluorinated compounds (PFCs), pharmaceutical and personal care products (PPCPs), radioactive elements, electronic waste, plastics, and nanoparticles. Some of these occur naturally in the environment, whilst others are produced from anthropogenic sources. They may contaminate our food-crops, livestock, and seafood-and drinking water and exert adverse effects on our health. It is important to perform assessments of the associated potential risks. Monitoring contamination levels, enactment of control measures including remediation, and consideration of sociopolitical implications are vital to provide safer food globally.

Fast and environmental-friendly methods for the determination of polybrominated diphenyl ethers and their metabolites in fish tissues and feed

Environmental-friendly, cost-effective and fast methods were developed and validated for the analysis of seven PolyBrominated Diphenyl Ethers (PBDEs) and eight methoxylated PBDEs (MeO-PBDEs) in three distinct seafood matrices (muscle, liver and plasma) and feed using a Quick, Easy, Cheap, Efficient, Rugged and Safe (QuEChERS) extraction approach for solid samples and a Dispersive Liquid-Liquid Microextraction method (DLLME) for plasma. Instrumental analyses were performed with gas chromatography coupled to triple quadrupole mass spectrometry using electron impact source (GC-EI-MS/MS) and negative ion chemical ionization (GC-NICI-MS) to assess BDE-209. Statistical validation showed recoveries for all target substances near 100% with average Relative Standard Deviation (RSD) lower than 9% and recovery standards higher than 65% (average RSD below 20%). Average calculated Method Detection Limits (MDLs) were lower than 65 pg·g^-1 wet weight (WW) for muscle, 5.35 ng·g^-1 WW for liver, 4.50 ng·g^-1 WW for feed, and 0.60 ng·mL^-1 for plasma samples. Quality assurance and quality control practices were comprehensively described. Methods scored high in an analytical Eco-scale, thus being classified as "an excellent green analysis". Finally, real seafood samples collected in local markets and local fishermen were analyzed. Positive samples presented both PBDEs and MeO-PBDEs in safe amounts (0.28-125.80 ng·g^-1 WW) for human consumption.

Adsorption-desorption of hydrophilic contaminants rhodamine B with/without Cd2+ on a coastal soil: implications for mariculture and seafood safety

An experimental study on adsorption and desorption behaviors of rhodamine B (RhB) with/without cadmium ion (Cd²⁺) on a coastal soil was carried out in the face of the scarce studies on its environmental behaviors, especially its combined pollution with metal ions. The implications on mariculture and seafood safety, rarely concerned either, were also analyzed for providing a new insight between azo dyes and them. It showed that the adsorption of RhB on the tested soil was affected by Cd²⁺ and could be better fitted by the Freundlich model and dominantly identified as chemical adsorption according to the threshold of ΔG⁰ (40 kJ/mol). There is a positive hysteresis on the desorption of RhB, which was generally strengthened with the increasing concentration of RhB but generally weakened in the presence of Cd²⁺. The azo dyes including RhB and heavy metals such as Cd, as the major class of typical pollutants in coastal environment, are closely related to the mariculture and seafood safety. In the consideration of three aspects including potential pollutants for the mariculture, potential risks for seafood safety, and potential relationships between dyes and mariculture and seafood safety, their implications were further clarified.

Factors influencing risk assessments of brominated flame-retardants; evidence based on seafood from the North East Atlantic Ocean

Brominated flame-retardants (BFRs) such as polybrominated diphenyl ethers (PBDE) and hexabromocyclododecane (HBCD) are considered hazardous to human health. Due to their persistence, they are still present in the environment and in biota and seafood is major contributor of BFRs to human exposure. Here, we used data from >9700 samples of wild and farmed fish, fish feed and fish feed ingredients collected from the North Atlantic between 2006 and 2016 aiming to investigate factors influencing the risk assessments of BFRs. Due to most representative number of analyses, PBDEs were the main focus of investigation. Mean ∑PBDE in fillet samples ranged from below quantification in Atlantic cod fillet to 2.0 μg kg^-1 in Atlantic halibut. The main congener contributing to the ∑PBDE in all species was BDE 47. Factors affecting the level of BFR in seafood were multifaceted, and the levels were within species mainly determined by fish age, geographical origin and time of sampling. BDE 47, 99, 153 and HBCD were selected for margin of exposure (MOE) evaluation. When other sources of BFR than seafood were excluded, our risk assessment showed low risk at the current dietary intake of seafood. However, the dietary intake of BDE 99 may be of concern for toddlers when all sources are considered. The choice of fish species, dietary studies, choice of statistics, as well as exposure from other sources than seafood, were all factors that influenced the final MOE of BFRs. We propose the use of regression on order statistics as a tool for risk assessment, to illustrate means and spreads in large surveillance datasets to avoid the issue of measurements below the limit of quantification. A harmonized, updated evaluation of the risk associated with exposure to BFRs from diet, air and dust is warranted, where the fish species most commonly consumed also is taken into consideration.

Brominated flame retardants: Recommendation for different listing under the Hong Kong Convention

When the Hong Kong International Convention for the Safe and Environmentally Sound Recycling of Ships, 2009 enters into effect, ships to be sent for recycling will be required to carry an Inventory of Hazardous Materials (IHM) on board, which identifies the hazardous materials contained in the ship's structure or equipment. In its current form, IHM covers two classes of brominated flame retardants (BFRs), namely polybrominated biphenyls and polybrominated diphenyl ethers. Emerging evidence from recent literature suggests that members of all classes of BFRs are present in all environmental compartments and that exposure to them is associated with a wide range of harmful effects in humans and animals, effects that include endocrine disruption. Despite a growing body of research, the necessary data to perform health and environmental risk assessment are still lacking. This paper reviews environmental and human health impacts and discusses some issues of BFR environmental management. It is suggested that based on a precautionary approach, the inclusion of all classes of BFRs in IHM is warranted.

Spatial Distribution of Novel and Legacy Brominated Flame Retardants in Soils Surrounding Two Australian Electronic Waste Recycling Facilities

Informal recycling of electronic waste (e-waste) has been shown to cause significant brominated flame retardant (BFR) contamination of surrounding soils in a number of Asian and West African countries. However, to the authors' knowledge, there have been no published studies demonstrating polybrominated diphenyl ether (PBDE) and novel brominated flame retardant (NBFR) soil contamination from regulated "formal" e-waste processing facilities in developed countries. This study reports on PBDEs (-28, -47, -99, -100, -153, -154, -183, and -209) and NBFRs (PBT, PBEB, HBB, EH-TBB, BTBPE and DBDPE) in 36 soil samples surrounding two Australian e-waste recycling plants and a further eight reference soils. Overall ∑PBDE concentrations ranged 0.10-98 000 ng/g dw (median; 92 ng/g dw) and ∑NBFRs ranged ND-37 000 ng/g dw (median 2.0 ng/g dw). Concentrations in soils were found to be significantly negatively associated with distance from one of the e-waste facilities for ∑penta-BDEs, BDE-183, BDE-209, and ∑NBFR compound groups. ANOVA tests further illustrated the potential for e-waste recycling to significantly elevate concentrations of some BFRs in soils over distances up to 900 m compared to references sites. This study provides the first evidence of soil contamination with PBDEs and NBFRs originating from formal e-waste recycling facilities in Australia, which may have implications for e-waste recycling practices throughout the world.

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.

Fish energy budget under ocean warming and flame retardant exposure

Climate change and chemical contamination are global environmental threats of growing concern for the scientific community and regulatory authorities. Yet, the impacts and interactions of both stressors (particularly ocean warming and emerging chemical contaminants) on physiological responses of marine organisms remain unclear and still require further understanding. Within this context, the main goal of this study was to assess, for the first time, the effects of warming (+ 5 °C) and accumulation of a polybrominated diphenyl ether congener (BDE-209, brominated flame retardant) through dietary exposure on energy budget of the juvenile white seabream (Diplodus sargus). Specifically, growth (G), routine metabolism (R), excretion (faecal, F and nitrogenous losses, U) and food consumption (C) were calculated to obtain the energy budget. The results demonstrated that the energy proportion spent for G dominated the mode of the energy allocation of juvenile white seabream (56.0-67.8%), especially under the combined effect of warming plus BDE-209 exposure. Under all treatments, the energy channelled for R varied around 26% and a much smaller percentage was channelled for excretion (F: 4.3-16.0% and U: 2.3-3.3%). An opposite trend to G was observed to F, where the highest percentage (16.0 ± 0.9%) was found under control temperature and BDE-209 exposure via diet. In general, the parameters were significantly affected by increased temperature and flame retardant exposure, where higher levels occurred for: i) wet weight, relative growth rate, protein and ash contents under warming conditions, ii) only for O:N ratio under BDE-209 exposure via diet, and iii) for feed efficiency, ammonia excretion rate, routine metabolic rate and assimilation efficiency under the combination of both stressors. On the other hand, decreased viscerosomatic index was observed under warming and lower fat content was observed under the combined effect of both stressors. Overall, under future warming and chemical contamination conditions, fish energy budget was greatly affected, which may dictate negative cascading impacts at population and community levels. Further research combining other climate change stressors (e.g. acidification and hypoxia) and emerging chemical contaminants are needed to better understand and forecast such biological effects in a changing ocean.

Emerging brominated flame retardants and dechlorane-related compounds in European eels (Anguilla anguilla) from Latvian lakes

Fifteen halogenated flame retardants (HFRs) including seven emerging brominated flame retardants (EBFRs) and eight dechlorane-related compounds (DRCs) were analyzed in eels (Anguilla anguilla) sampled from five Latvian lakes. Out of the seven EBFRs, hexabromocyclododecane (HBCD) and decabromodiphenyl ethane (DBDPE) were found in eels in quantifiable concentrations, up to 6.58 and 33.0 ng g^-1 lipid weight (l.w.), respectively. The mean total concentration of DRCs (∑_DRC) in the samples was 0.62 ng g^-1 l.w. and the geographical distribution of DRC contamination was nearly uniform among the selected lakes. Dechlorane 602 (Dec 602) was the predominant component, whereas the composition of mixture containing syn- and anti-Dechlorane Plus (DP) stereoisomers showed a pronounced enrichment of the anti-DP isomer and was close to the composition of OxyChem^® DP commercial product. The determined concentrations of HFRs were lower than in other studies of aquatic biota from Europe and Asia, and the obtained results reflect the acceptable environmental status of Latvian lakes with regard to the total content of HBCD (∑_HBCD), considering the environmental quality standards (EQS) stated in the Directive 2013/39/EU. The highest ∑_HBCD levels were observed in eels from lakes corresponding to the industrialization of those areas, while the results of principal component analysis (PCA) showed that the concentration of HBCD depended on the particular sampling lake, reflecting non-uniform contamination of the Latvian environment with this EBFR.

Concentrations of legacy and novel brominated flame retardants in indoor dust in Melbourne, Australia: An assessment of human exposure

Polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (NBFR) have been used in a range of polymers to inhibit the spread of fires but also have a propensity to migrate out of consumer materials and contaminate indoor dust. In this study, a total of 57 dust samples were collected from 12 homes, eight offices and eight vehicles in Melbourne, Australia and analysed for eight PBDEs (-28, -47, -99, -100, -153, -154, -183 and -209) and seven NBFRs (PBT, PBEB, HBB, EH-TBB, BEH-TEBP, BTBPE and DBDPE) to determine human exposure risks from dust ingestion. Samples were analysed using selective pressurized liquid extraction (S-PLE) and gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). Legacy and replacement flame retardants were detected in all samples with overall ∑PBDE concentrations ranging from 120 to 1700,000 ng/g (median 2100 ng/g) and ∑NBFRs ranging from 1.1 to 10,000 ng/g (median 1800 ng/g). BDE-209 and DBDPE were the dominant compounds in dust samples, followed by congeners associated with commercial Penta-BDE formulations (-47, -99, -100, -153 and -154) and then EH-TBB of the FireMaster 550 and BZ-54 products. ∑Penta-BDE concentrations were elevated in office samples compared with homes and vehicles, while EH-TBB and BDE-209 measured higher concentrations in vehicles compared with their respective levels in homes and offices. Risk assessment estimates revealed the majority of exposure to occur in the home for both adults and toddlers in the City of Melbourne. Generally, body weight adjusted exposure to PBDEs and NBFRs was predicted to be 1 to 2 orders of magnitude higher for toddlers than adults. Estimated rates of BDE-47, -99, -153 and -209 ingestion were each 2 orders of magnitude or more below the USEPA's prescribed oral reference dose values (RfDs) for typical exposure scenarios. However, exposure rates for BDE-47 and -99 reached as high as 52 and 95% of RfDs, respectively, for adults and 4.4 and 7.4%, respectively, for toddlers in high exposure scenarios. This study provides the first wide-ranging survey of NBFRs in indoor dust from homes, offices and vehicles in Australia and offers further evidence of human exposure to legacy and novel brominated flame retardants via dust ingestion.