Spatio-temporal variations and input patterns on the legacy and novel brominated flame retardants (BFRs) in coastal rivers of North China

A review of occurrence, bioaccumulation, and fate of novel brominated flame retardants in aquatic environments: A comparison with legacy brominated flame retardants

Novel brominated flame retardants (NBFRs) have been developed as replacements for legacy brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs). The prevalence of NBFRs in aquatic environments has initiated intense concerns that they resemble to BFRs. To comprehensively elucidate the fate of NBFRs in aquatic environments, this review summarizes the physico-chemical properties, distribution, bioaccumulation, and fates in aquatic environments. 1,2-bis(2,3,4,5,6-pentabromophenyl) ethane (DBDPE) as the major substitute for PBDEs is the primary NBFR. The release from industrial point sources such as e-waste recycling stations is the dominant way for NBFRs to enter the environment, which results in significant differences in the regional distribution of NBFRs. Sediment is the major sink of NBFRs attributed to the high hydrophobicity. Significantly, there is no decreasing trend of NBFRs concentrations, while PBDEs achieved the peak value in 1970-2000 and decreased gradually. The bioaccumulation of NBFRs is reported in both field studies and laboratory studies, which is regulated by the active area, lipid contents, trophic level of aquatic organisms, and the log KOW of NBFRs. The biotransformation of NBFRs showed similar metabolism patterns to that of BFRs, including debromination, hydroxylation, methoxylation, hydrolysis, and glycosylation. In addition, NBFRs show great potential in trophic magnification along the aquatic food chain, which could pose a higher risk to high trophic-level species. The passive uptake by roots dominates the plant uptake of NBFRs, followed by acropetal and basipetal bidirectional transportation between roots and leaves in plants. This review will provide the support to understand the current pollution characteristics of NBFRs and highlight perspectives for future research.

Mercury contamination is an invisible threat to declining migratory shorebirds along the East Asian-Australasian Flyway

Exposure to pollutants is a potentially crucial but overlooked driver of population declines in shorebirds along the East Asian-Australasian Flyway. We combined knowledge of moult strategy and life history with a standardised sampling protocol to assess mercury (Hg) contamination in 984 individuals across 33 migratory shorebird species on an intercontinental scale. Over one-third of the samples exceeded toxicity benchmarks. Feather Hg was best explained by moulting region, while habitat preference (coastal obligate vs. non-coastal obligate), the proportion of invertebrates in the diet and foraging stratum (foraging mostly on the surface vs. at depth) also contributed, but were less pronounced. Feather Hg was substantially higher in South China (Mai Po and Leizhou), Australia and the Yellow Sea than in temperate and Arctic breeding ranges. Non-coastal obligate species (Tringa genus) frequently encountered in freshwater habitats were at the highest risk. It is important to continue and expand biomonitoring research to assess how other pollutants might impact shorebirds.

Occurrence, bioaccumulation, fate, and risk assessment of emerging pollutants in aquatic environments: A review

Significant concerns on a global scale have been raised in response to the potential adverse impacts of emerging pollutants (EPs) on aquatic creatures. We have carefully reviewed relevant research over the past 10 years. The study focuses on five typical EPs: pharmaceuticals and personal care products (PPCPs), per- and polyfluoroalkyl substances (PFASs), drinking water disinfection byproducts (DBPs), brominated flame retardants (BFRs), and microplastics (MPs). The presence of EPs in the global aquatic environment is source-dependent, with wastewater treatment plants being the main source of EPs. Multiple studies have consistently shown that the final destination of most EPs in the water environment is sludge and sediment. Simultaneously, a number of EPs, such as PFASs, MPs, and BFRs, have long-term environmental transport potential. Some EPs exhibit notable tendencies towards bioaccumulation and biomagnification, while others pose challenges in terms of their degradation within both biological and abiotic treatment processes. The results showed that, in most cases, the ecological risk of EPs in aquatic environments was low, possibly due to potential dilution and degradation. Future research topics should include adding EPs detection items for the aquatic environment, combining pollution, and updating prediction models.

Distribution, sources, and eco-risk of Current-Use Pesticides (CUPs) in the coastal waters of the northern Shandong Peninsula, China

This study investigated the spatial distributions and seasonal variations of 19 CUPs in the coastal areas of the Shandong Peninsula and its surrounding rivers and assessed their ecological risk. In freshwater and seawater, insecticides (chlorpyrifos, methoxychlor, and pyridaben), as well as fungicides (fenarimol) and herbicides (dichlobenil) were the main pollutants (Detection Frequency: 100 %). Spatially, during winter, the regional pollution levels of Σ19CUPs in seawater showed a trend of Laizhou Bay (LZB, mean:4.13 ng L-1) > Yellow River Estuary (YRE, mean:2.57 ngL-1) > Bohai Bay (BHB, mean:2.21 ng L-1) > Yanwei Area (YWA, mean:1.94 ng L-1). The similarities of major substances between rivers and the marine environment suggest that river discharge is the main source of CUPs pollution in coastal areas. In summer, CUPs in rivers posed a high risk. In winter, the risk significantly decreased, indicating a moderate overall risk. Seawater exhibited a low risk in winter.

Distribution characteristics and migration trends of hexabromocyclododecanes between seawater-sediment system in different seasons of fishing grounds along the Yellow sea and East China sea coasts

Pollutants in the ecological environment of fishery seawater are harmful to the survival and reproduction of aquatic organisms. Hexabromocyclododecanes (HBCDs) were 42.9% detected within ND-48.89 ng/L in 177 seawater samples and 30.7% within ND-1.07 ng/g dw in 88 sediment samples of the fisheries in the Yellow Sea and East China Sea, respectively. γ-HBCD accounted for 65% of seawater and 89% of sediment samples. HBCDs in seawater in winter (ND-48.89 ng/L) were significantly higher than in summer (ND-4.99 ng/L), possibly because the re-suspension caused by winds and waves could re-migrate HBCDs from the sediment to the seawater in winter. However, seasonal differences of HBCDs in sediment were not significant. The fugacities indicated HBCDs' migrating trend from seawater to sediment due to their hydrophobic nature. There is almost no terrestrial input of HBCDs from the Yangtze and Yellow Rivers, and currently used fishery materials in marine may compose long-lasting sources of HBCDs.

A review of polybrominated diphenyl ethers and novel brominated flame retardants in Chinese aquatic environment: Source, occurrence, distribution, and ecological risk assessment

Due to the widespread commercial production and use of brominated flame retardants (BFRs) in China, their potential impact on human health development should not be underestimated. This review searched the literature on Polybrominated diphenyl ethers and Novel brominated flame retardant (PBDEs and NBFRs) (broad BFRs) in the aquatic environment (including surface water and sediment) in China over the last decade. It was found that PBDEs and NBFRs entered the aquatic environment through four main pathways, atmospheric deposition, surface runoff, sewage effluent and microplastic decomposition. The distribution of PBDEs and NBFRs in the aquatic environment was highly correlated with the local economic structure and population density. In addition, a preliminary risk assessment of existing PBDEs and PBDEs in sediments showed that areas with high-risk quotient values were always located in coastal areas with e-waste dismantling sites, which was mainly attributed to the historical legacy of electronic waste. This research provides help for the human health development and regional risk planning management posed by PBDEs and NBFRs.

New brominated flame retardant decabromodiphenyl ethane (DBDPE) in water sediments: A review of contamination characteristics, exposure pathways, ecotoxicological effects and health risks

As an alternative to polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE) has become one of the most important new brominated flame retardants (NBFRs). However, little is known about whether this emerging contaminant may has an environmental fate similar to PBDEs. Sediments are the main sink for DBDPE in the aqueous phase. Worldwide concentration data, since it was first found in sediments to date, have been collated, and the following conclusions have been drawn. (1) DBDPE concentrations in sediments have increased rapidly, often with a higher risk of contamination in source discharge areas. Compared with other countries, DBDPE contamination in China is more severe, especially in Guangdong Province, which is closely related to its being an e-waste dismantling area. (2) The amount of DBDPE in surface sediments has exceeded that of legacy brominated flame retardants (BFRs), and data recorded in sediment cores also corroborate that DBDPE is replacing decabromodiphenyl ether (BDE-209) as one of the most dominant NBFRs in the environment. (3) The exposure pathways of DBDPE include dietary intake, air or indoor dust intake, cutaneous absorption and endogenous exposure. For sediments, dietary exposure and endogenous exposure pathways need to be considered. Sediment DBDPE can enter the human body through bioenrichment such as contaminated seafood and the food chain. (4) DBDPE can exhibit neurotoxicity, thyrotoxicity, reproductive and developmental toxicity, hepatotoxicity and oxidative stress in organisms. Long-term DBDPE exposure may increase hyperthyroidism risk and inhibit normal cells activity. This review focuses on the distribution characteristics and exposure risks of DBDPE in global water sediments, providing a strong reference for environmental management and related legal policy formulation. The next steps are to focus on continuous source monitoring, process control and sediment clean-up of DBDPE. The development of sustainable water management options for waste microplastics (MPs) and e-waste spiked with DBDPE is a priority.

Legacy and novel brominated flame retardants in a lab-constructed freshwater ecosystem: Distribution, bioaccumulation, and trophic transfer

The extensive utilization of both legacy and novel brominated flame retardants (BFRs) leads to high environmental concentrations, which would be bioaccumulated by organisms and further transferred through the food webs, causing potential risks to humans. In this study, five BFRs, that showed high detection frequencies and concentrations in sediments from an e-waste dismantling site in Southern China, namely 2,3,4,5,6-pentabromotoluene (PBT), hexabromobenzene (HBB), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), decabromodiphenyl ethane (DBDPE), and decabromodiphenyl ether (BDE209), were selected as target pollutants in the lab-constructed aquatic food web as part of a micro-ecosystem, to investigate their distribution, bioaccumulation, and trophic transfer patterns. The significant correlations between different samples in the food web indicated that the dietary uptake appeared to influence the levels of BFRs in organisms. Significant negative correlations were observed between the trophic level of organisms and the lipid-normalized concentrations of BTBPE and DBDPE, indicating the occurrence of trophic dilution after 5-month exposure. However, the average values of bioaccumulation factors (BAFs) were from 2.49 to 5.17 L/kg, underscoring the importance of continued concern for environmental risks of BFRs. The organisms occupying higher trophic levels with greater bioaccumulation capacities may play a pivotal role in determining the trophic magnification potentials of BFRs. This research provides a helpful reference for studying the impacts of feeding habits on bioaccumulation and biomagnification, as well as for identifying the fate of BFRs in aquatic environment.

Emission and environmental distribution of decabromodiphenyl ethane (DBDPE) in China from 2006 to 2026: Retrospection, forecasting, and implications for assessment and management

Decabromodiphenyl ethane (DBDPE) is the main alternative to decabromodiphenyl ether (deca-BDE) in commercial use. However, there is increasing evidence show that DBDPE is a potential persistent organic pollutant, and it has been found ubiquitously in environmental media across China in recent years. Monitoring studies have not been able to determine the overall levels and temporal trends of DBDPE contamination in China, and have been unable to explain how emission patterns can affect their environmental distribution. Therefore, this study estimated the temporal variance of DBDPE emissions and environmental concentrations in five regions of China from 2006 to 2026 using the PROduction-To-EXposure (PROTEX) mass balance model. The results showed that Guangdong Province was the greatest DBDPE pollution hotspot in China due to emissions from plastics manufacturing and e-waste disposal; there was also severe pollution in Shandong Province, where almost all the DBDPE in China is produced. The DBDPE concentrations in indoor and outdoor environments increased substantially in all regions during 2006-2021. Furthermore, in Guangdong Province and Shandong Province, the ratio of indoor/outdoor air concentrations was greater than or close to 1, indicative of significant outdoor emission sources of DBDPE. In contrast, the ratios for the Beijing-Tianjin-Hebei region, East China, and Southwest China were below 1 due to the indoor use of electronic equipment containing DBDPE. The temporal trends of these ratios indicated that DBDPE contamination has gradually spread from high-concentration environments with strong emission sources to low-concentration environments. The outcomes of this study have important implications for the risk assessment of DBDPE use in China and can be used to establish contamination-mitigation actions.

Hemocytes in blue mussel Mytilus edulis adopt different energy supply modes to cope with different BDE-47 exposures

The energetic response of blue mussel Mytilus edulis when coping with tetrabromodiphenyl ether (BDE-47) exposure was evaluated from the perspective of alterations in energy supply mode, and the possible regulating mechanism was discussed based on a 21-day bioassay. The results showed that the energy supply mode changed with concentration: 0.1 μg/L BDE-47 decreased the activity of isocitrate dehydrogenase (IDH), succinate dehydrogenase (SDH), malate dehydrogenase and oxidative phosphorylation, suggesting inhibition of the tricarboxylic (TCA) acid cycle and aerobic respiration. The coincident increase in phosphofructokinase and the decrease in lactate dehydrogenase (LDH) indicated that glycolysis and anaerobic respiration were increased. When exposed to 1.0 μg/L BDE-47, M. edulis mainly utilized aerobic respiration, but lowered glucose metabolism as indicated by the decrease in glutamine and l-leucine was suggested to be involved in this process, which was differed from that in the control. The reoccurrence of IDH and SDH inhibition as well as LDH elevation indicated attenuation of aerobic and anaerobic respiration when the concentration increased to 10 μg/L, but severe protein damage was evidenced based on the elevation of amino acids and glutamine. Under the 0.1 μg/L BDE-47, activation of the AMPK-Hif-1a signaling pathway promoted the expression of glut1, which was the potential mechanism for the improvement of anaerobic respiration, and further activated glycolysis and anaerobic respiration. This study shows that the energy supply mode experienced a conversion from aerobic respiration under normal conditions to anaerobic mode in the low BDE-47 treatment and back to aerobic respiration with increasing BDE-47 concentrations, which may represent a potential mechanism for mussel physiological responses when faced with different levels of BDE-47 stress.

Decabromodiphenyl ethane induced hyperactivity in developing zebrafish at environmentally relevant concentrations

Decabromodiphenyl ethane (DBDPE), a widely used novel brominated flame retardant, is gaining concerns due to rapidly increased contents in various environmental and biota samples. In the present study, zebrafish (Danio rerio) embryos were exposed to 2.91, 9.71, 29.14 and 97.12 μg/L of DBDPE until 120 h post-fertilization (hpf) to investigate the potential developmental neurotoxicity and underlying mechanisms. Chemical analysis revealed concentration-dependently increased body burdens of DBDPE in zebrafish larvae, with bioaccumulation factors (BCFs) ranging from 414 to 726. Embryonic exposure to DBDPE caused hyperactivity without affecting the development of secondary motoneuron axons and muscle fibers. However, further results implicated that DBDPE may affect the locomotor regulatory network via different mechanisms at lower and higher concentrations. On the one hand, embryonic exposure to 2.91 μg/L DBDPE transiently promoted spontaneous coiling contractions, but showed no effects on touch-response and swimming activity in zebrafish larvae. The whole-body contents of neurotransmitters were significantly decreased. Significant decreased protein abundances of α1-TUBULIN and SYN2a and molecular docking results pointed out possible interactions of DBDPE with these two proteins. However, these changes may be unconcerned with the transient hyperactivity, and the exact molecular mechanisms need further investigation. On the other hand, 29.14 and 97.12 μg/L DBDPE exposure caused longer-lasting effects in promoting spontaneous coiling contractions, and also touch-response and swimming activity. At the same time, increased ACh contents (without changes of other neurotransmitters) and ChAT activity and inhibited transcription of nAChRs were observed at higher concentrations. Molecular docking indicated direct interaction of DBDPE with ChAT. The results suggested that DBDPE induced hyperactivity at higher concentrations was probably involved with disrupted cholinergic system, with ChAT as a potential target. Given that the body burden of DBDPE in lower concentration group was comparable with those detected in wild fish, the current results may provide useful information for ecological risk assessment.

Fate and toxicity of legacy and novel brominated flame retardants in a sediment-water-clam system: Bioaccumulation, elimination, biotransformation and structural damage

Due to the characteristics of persistent organic pollutants (POPs), some legacy brominated flame retardants (LBFRs) were prohibited from use, and then gradually replaced by novel brominated flame retardants (NBFRs). However, till now little research focused on the effects of NBFRs on the benthos. In the present study, 0.5, 5, and 50 mg/kg dw of pentabromotoluene (PBT), hexabromobenzene (HBB), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), decabromodiphenyl ethane (DBDPE) and decabromodiphenyl ether (BDE209) were added into sediments to test freshwater clams (Corbicula fluminea). In the 35-day exposure experiment, C. fluminea had different enrichment behaviors in three treatment groups. It was conjectured that in the lower dose group, the clams ingested contaminants and tended to be stable over time. While in higher dose groups, the clams were induced by the chemicals, leading to the changes in physiological activities so that the concentrations showed a downward trend first and then went up. The half-lives of contaminants in freshwater clams were between 0.911 and 11.6 days. DBDPE showed stronger bioaccumulation ability than BDE209 in this study. Parabolic relationships were observed between log BSAF and log K_ow values in clam tissues. Debromination, hydroxylation, and methoxylated products were detected. Additionally, the gill samples of C. fluminea exposed to 50 mg/kg dw of single substance were observed by scanning electron microscope (SEM), indicating that the adhesions, tissue hyperplasia, and messy cilia occurred on the surface. Our research potentially contributes to further evaluations of the environmental risks posed in sediments contaminated by PBT, HBB, BTBPE, DBDPE, and BDE209, particularly the benthic organisms.

Physiologically based pharmacokinetic (PBPK) modeling of BDE-209 following oral exposure in Chinese population

The wide usage of decabromodiphenyl ether (BDE-209) as additive brominated flame retardant has caused its widespread occurrence in the environment and high exposure risk in humans. Estimating its internal exposure dose and reconstruction of external exposure dose using physiologically based pharmacokinetic (PBPK) modelling approach is a key step in the risk assessment of BDE-209. However, the PBPK model for BDE-209 is currently unavailable. This study has established two oral permeability-limited PBPK models of BDE-209 without enterohepatic recirculation (EHR) (model 1) and with EHR (model 2) for Chinese population. Using the in vitro experiments, the average binding of BDE-209 to human plasma protein (99.64% ± 2.97%) was obtained. Moreover, blood sample analysis and systematic literature review were performed to obtain internal and external exposure data of BDE-209 used for model calibration and validation. The predictions of both models were within 2-fold of the observed, and a longer half-life of serum BDE-209 was observed in model 2 than model 1. Based on the models, a human biomonitoring guidance value (HBM-GV) of 93.61 μg/g lw was derived for BDE-209, and there is no health risk found for Chinese population currently. This study provides new quantitative assessment tools for health risk assessment of BDE-209.

Occurrence of persistent organic pollutants (POPs) in the atmosphere of South Korea: A review

Numerous studies found the presence of persistent organic pollutants (POPs) in various environmental compartments, including air, water, and soil. POPs have been discovered in various industrial and agricultural products with severe environmental and human health consequences. According to the data, South Korea is a hotspot for POP pollution in the southern part of Asia; hence, South Korea has implemented the Stockholm Convention's National Implementation Plan (NIP) to address this worldwide issue. The purpose of this review is to assess the distribution pattern of POPs pollution in South Korea's atmosphere. According to findings, PAHs, PCBs, BFRs, and PBDEs significantly polluted the atmosphere of South Korea; however, assessing their exposure nationwide is difficult due to a shortage of data. The POPs temporal trend and meta-analysis disclosed no proof of a decrease in PAHs and BFRs residues in the atmosphere. However, POP pollution in South Korea tends to decrease compared to contamination levels in neighboring countries like Japan and China.

PBDEs in the marine environment: Sources, pathways and the role of microplastics

Brominated flame retardants (BFRs) are an important group of additives in plastics that increase resistance to ignition and slow down the rate of burning. Because of concerns about their environmental and human health impacts, however, some of the most widely employed BFRs, including hexabromocyclododecane (HBCD) and commercial mixtures of penta-, octa- and deca- (poly)bromodiphenyl ethers (PBDEs), have been restricted or phased out. In this review, the oceanic sources and pathways of PBDEs, the most widely used BFRs, are evaluated and quantified, with particular focus on emissions due to migration from plastics into the atmosphere versus emissions associated with the input of retarded or contaminated plastics themselves. Calculations based on available measurements of PBDEs in the environment suggest that 3.5 and 135 tonnes of PBDEs are annually deposited in the ocean when scavenged by aerosols and through air-water gas exchange, respectively, with rivers contributing a further ∼40 tonnes. Calculations based on PBDE migration from plastic products in use or awaiting or undergoing disposal yield similar net inputs to the ocean but indicate a relatively rapid decline over the next two decades in association with the reduction in the production and recycling of these chemicals. Estimates associated with the input of PBDEs to the ocean when "bound" to marine plastics and microplastics range from about 360 to 950 tonnes per year based on the annual production of plastics and PBDEs over the past decade, and from about 20 to 50 tonnes per annum based on the abundance and distribution of PBDEs in marine plastic litter. Because of the persistence and pervasiveness of plastics in the ocean and diffusion coefficients for PBDEs on the order of 10^-20 to 10^-27 m² s^-1, microplastics are likely to act as a long-term source of these chemicals though gradual migration. Locally, however, and more important from an ecotoxicological perspective, PBDE migration may be significantly enhanced when physically and chemically weathered microplastics are exposed to the oily digestive fluids conditions of fish and seabirds.

Habitat-dependent trophic transfer of legacy and emerging halogenated flame retardants in estuarine and coastal food webs near a source region

With the phase-out of legacy halogenated flame retardants (HFRs), such as decabromodiphenyl ether (BDE-209), emerging ones, such as decabromodiphenyl ethane (DBDPE), are being widely produced. We conducted field campaigns to assess the trophic transfer of legacy and emerging HFRs in estuarine and coastal food webs of Laizhou Bay, which are located near the largest HFR manufacturing base in China. Seawater, sediment, plankton, invertebrates, and fish were collected from both sites. BDE-209 was the predominant compound in the estuary, whereas DBDPE was the main contributor to HFRs in the bay, followed by BDE-209. Invertebrates, especially bivalves and sea cucumbers, showed higher levels of BDE-209 and DBDPE than fish. The HFR levels in the organisms of the two coastal zones were comparable to each other, although their concentrations in the estuarine water were one order of magnitude higher than those in the bay. The HFR profiles in benthic organisms were similar to those in the sediments, indicating that the bioaccumulation of HFRs in coastal food webs depended on the habitat. The ΣHFR concentrations followed the order filter-feeding > carnivorous for invertebrates, and demersal non-migratory fish showed higher HFR levels than oceanodromous fish. The trophic magnification factors estimated for BDE-209, dechlorane plus, and DBDPE were lower than 1, suggesting biodilution potential in both food webs, whereas several PBDE congeners exhibited biomagnification capacity. Feeding habits, habitats, hydrophobicity, bioavailability, and metabolism may be the main factors impacting the bioaccumulation of HFRs in organisms in estuarine-coastal ecosystems of northern China.

Occurrence and ecological risk assessment of neonicotinoids and related insecticides in the Bohai Sea and its surrounding rivers, China

Systemic insecticides like neonicotinoids and the phenylpyrazole insecticide fipronil are the most widely applied insecticides around the world. Multiple studies analyzed insecticide residues in freshwater systems, but data on seawater contamination levels are scarce. This study investigates the spatiotemporal distribution and ecological risk assessment of fipronil, neonicotinoids, sulfoxaflor and selected transformation products (TPs) in the Chinese Bohai Sea and its surrounding rivers. Well-established neonicotinoids (acetamiprid, clothianidin, imidacloprid, thiacloprid and thiamethoxam) and TPs of fipronil and imidacloprid were frequently detected (detection frequency (DF): 42-100%) in freshwater. The median total insecticide concentration in freshwater was significantly higher in summer (72.4 ng•L-1) than in fall (23.4 ng•L-1), with major contributions from neonicotinoids, suggesting that pollution originates mostly from diffuse sources. In 2018, acetamiprid, desnitro-imidacloprid, fipronil-desulfinyl and thiacloprid were abundant in seawater (DF: 47-100%), indicating a high stability of acetamiprid and thiacloprid and a rapid photodegradation of fipronil and imidacloprid in surface waters. These results indicate that the continued use of these parent compounds may lead to their accumulation and/or of their TPs in shallow coastal seas. Consequently, this may lead to their transport to open seas, increasing their potential risk to marine organisms. Similarities between contaminant fingerprints in freshwater and seawater strongly suggest riverine discharges as main pollution source of adjacent coastal areas. This is the first study to perform an ecological risk assessment of fipronil, neonicotinoids, sulfoxaflor and selected TPs on marine ecosystems. Fipronil and its TPs demonstrated to be environmentally relevant with potential high risks for aquatic species. Our study provides novel insights into the fate and ecological risk of fipronil, neonicotinoids, sulfoxaflor and their TPs to marine species in shallow coastal seas.

Current pollution status, spatial features, and health risks of legacy and emerging halogenated flame retardants in agricultural soils across China

Soil is a major reservoir and a secondary source of semi-volatile organic chemicals, while studies on the pollution status of halogenated flame retardants (HFRs) in agricultural soils are limited. In this study, a total of twenty-five chemicals including novel brominated flame retardants (NBFRs), polybrominated diphenyl ethers (PBDEs), and dechlorane plus (DPs) was analyzed in the agricultural soils across China to investigate the occurrence, spatial distribution, potential sources, influencing factors and their associated human health risks. The results showed that BDE-209 (125-130,183 pg/g, dry weight, d.w.) was the most abundant flame retardant of PBDEs, followed by decabromodiphenyl ethane (DBDPE) (9.27-22,864 pg/g, d.w.). Meanwhile, the DPs (anti-DP plus syn-DP) were in the range of ND-1229 pg/g (d.w.), and the range of f_anti values (the concentration of anti-DP divided by the sum of the concentrations of two isomers) in this study greatly matched those of commercial products, suggesting the effect of proximity to the source region. The higher levels of HFRs were found in Eastern and Southern regions of China. Spatial distribution implied that e-waste recycling activities and plastic processing have shown more importance in releasing legacy flame retardants (FRs) into the environment than the manufacturing process, while all are important for novel FRs. Correlation analysis between influencing factors and HFRs indicated that the distribution of most pollutants was more affected by anthropogenic source factors than environmental factors. The results of the principal component analysis demonstrated that deca-BDE and its alternative products were the major contributors to the sources of HFRs pollution. Human health risks assessment via oral intake and dermal contact pathways presented that the selected pollutants posed a no-carcinogenic risk to children and adults. It is worth noting that supervision of the disposal process of the NBFRs should be strengthened in the future.

Pesticides, nonylphenols and polybrominated diphenyl ethers in marine bivalves from France: A pilot study

The present pilot study aimed to provide an overview of organic contaminant concentration levels in the littoral ecosystems of the Pertuis seas. The study determined the concentrations of twenty-nine pesticides, six nonylphenols and seven polybrominated diphenyl ethers (PBDEs) in sediments, seawater, Pacific oysters and blue mussels. Oysters accumulated a higher number of pesticides than blue mussels. Indeed, alpha BHC (0.60-0.72 ng/g, ww), chlorfenvinphos (1.65-2.12 ng/g, ww), chlorpyrifos (0.79-0.93 ng/g, ww), chlortoluron (2.50-4.31 ng/g, ww), metolachlor (up to 0.38 ng/g, ww) and parathion (0.56-0.69 ng/g, ww) were quantified in oysters whereas only alpha BHC (0.24-0.31 ng/g, ww), was quantified in mussels. The present results also revealed that the POPs detected in water or sediments were not ultimately found accumulated in bivalves. Other molecules such as methylparathion and BDE47 were quantified in sediments. These molecules, BDE99 and one nonylphenol (OP2OE) were quantified in seawater. Finally, the comparison with the available environmental guidelines showed that the values measured were at concentrations not considered to cause adverse effects at the populations' level except for chlortoluron in seawater (15-50 ng/L).