Effects of Dechlorane Plus exposure on axonal growth, musculature and motor behavior in embryo-larval zebrafish

Developmental neurobehavioral toxicity of Dechlorane Plus (DP) was investigated using the embryo-larval stages of zebrafish (Danio rerio). Normal fertilized embryos were waterborne exposed to DP at 15, 30, 60 μg/L beginning from 6 h post-fertilization (hpf). Larval teratology, motor activity, motoneuron axonal growth and muscle morphology were assessed at different developmental stages. Results showed that DP exposure significantly altered embryonic spontaneous movement, reduced touch-induced movement and free-swimming speed and decreased swimming speed of larvae in response to dark stimulation. These changes occurred at DP doses that resulted no significant teratogenesis in zebrafish. Interestingly, in accord with these behavioral anomalies, DP exposure significantly inhibited axonal growth of primary motoneuron and induced apoptotic cell death and lesions in the muscle fibers of zebrafish. Furthermore, DP exposure at 30 μg/L and 60 μg/L significantly increased reactive oxygen species (ROS) and malondialdehyde (MDA) formation, as well as the mRNA transcript levels of apoptosis-related genes bax and caspase-3. Together, our data indicate that DP induced neurobehavioral deficits may result from combined effects of altered neuronal connectivity and muscle injuries.

Current halogenated flame retardant concentrations in serum from residents of Shandong Province, China, and temporal changes in the concentrations

The residents of Shandong Province, China, are exposed to high concentrations of halogenated flame retardants because large amounts of halogenated flame retardants are produced in the province. We determined the concentrations of eight polybrominated diphenyl ether congeners (PBDEs), seven novel brominated flame retardants (NBFRs), and the two dechlorane plus isomers (DPs) in serum from residents of Shandong Province. The aim was to identify temporal trends in the concentrations of these pollutants. The mean total concentrations of PBDEs, NBFRs and DPs were 41, 2.2 and 2.1ng/g lipid in pooled serum samples collected in 2014, and were 32, 3.5 and 3.1ng/g lipid in pooled serum samples collected in 2015, respectively. Decabromodiphenyl ether was the dominant PBDE congener in all of the samples. The novel brominated flame retardant and dechlorane plus concentrations were between one and two orders of magnitude lower than the PBDE concentrations. The PBDE concentrations in serum decreased significantly between 2007 and 2015, but the pentabromobenzene, pentabromotoluene, and dechlorane plus concentrations were relatively stable.

Occurrence of classic and emerging halogenated flame retardants in sediment and sludge from Ebro and Llobregat river basins (Spain)

Classic (polybromodiphenyl ethers, PBDEs) and emerging halogenated flame retardants such as hexabromobenzene (HBB), pentabromoetilbenzene (PBEB), decabromodiphenyl ethane (DBDPE), Dechlorane 602 (Dec 602), Dechlorane 603 (Dec 603), Dechlorane 604 (Dec 604) and Dechlorane plus (DP) were analyzed in 33 sediments and 7 sludges from two Iberian river basins, Ebro and Llobregat. In sediment samples, PBDE levels ranged between nd and 44.3ng/g dw with BDE-209 being the most abundant congener. Levels of DBDPE and halogenated norbornenes ranged between nd and 31.5ng/g dw and between nq and 3.74ng/g dw, respectively. This is the first study to report halogenated norbornene levels in sediment samples from Spain. PBDE, DBDPE and halogenated norbornene levels in sludge ranged from 13 to 340, nq to 124 and 2.7 to 19ng/g dw, respectively. HBB and PBEB were not detected in any sample. Levels of classic and emerging HFRs were compared. Our results suggest that DBDPE is the most frequently used compound to replace BDE-209, whereas the use of halogenated norbornenes is still low.

Dermal uptake and percutaneous penetration of ten flame retardants in a human skin ex vivo model

The dermal uptake and percutaneous penetration of ten organic flame retardants was measured using an ex vivo human skin model. The studied compounds were DBDPE, BTBPE, TBP-DBPE, EH-TBB, BEH-TEBP, α, β and γ-HBCDD as well as syn- and anti-DDC-CO. Little or none of the applied flame retardants was recovered in either type of the receptor fluids used (physiological and worst-case). However, significant fractions were recovered in the skin depot, particularly in the upper skin layers. The primary effect of the worst-case receptor fluid was deeper penetration into the skin. The recovered mass was used to calculate lower- and upper-bound permeability coefficients kp. Despite large structural variation between the studied compounds, a clear, significant decreasing trend of kp was observed with increasing log Kow. The results indicate that the dermis may provide a significant barrier for these highly lipophilic compounds. However, based on our results, dermal uptake should be considered in exposure assessments, though it may proceed in a time-lagged manner compared to less hydrophobic compounds.

Measurement and health risk assessment of PM2.5, flame retardants, carbonyls and black carbon in indoor and outdoor air in kindergartens in Hong Kong

Indoor air pollution is closely related to children's health. Polybrominated diphenyl ethers (PBDEs) and dechlorane plus (DP) transmitted through indoor PM_2.5 and dust, along with carbonyl compounds and black carbon (BC) aerosol were analysed in five Hong Kong kindergartens. The results showed that 60% of the median PM_2.5 levels (1.3×10¹ to 2.9×10¹μg/m³ for indoor; 9.5 to 8.8×10¹μg/m³ for outdoor) in the five kindergartens were higher than the guidelines set by the World Health Organization (2.5×10¹μg/m³). Indoor PM_2.5 mass concentrations were correlated with outdoor PM_2.5 in four of the kindergartens. The PBDEs (0.10-0.64ng/m³ in PM_2.5; 0.30-2.0×10²ng/g in dust) and DP (0.05-0.10ng/m³ in PM_2.5; 1.3-8.7ng/g in dust) were detected in 100% of the PM_2.5 and dust samples. Fire retardant levels in the air were not correlated with the levels of dust in this study. The median BC concentrations varied by >7-fold from 8.8×10²ng/m^-3 to 6.7×10³ng/m^-3 and cooking events might have caused BC concentrations to rise both indoors and outdoors. The total concentrations of 16 carbonyls ranged from 4.7×10¹μg/m³ to 9.3×10¹μg/m³ indoors and from 1.9×10¹μg/m³ to 4.3×10¹μg/m³ outdoors, whilst formaldehyde was the most abundant air carbonyl. Indoor carbonyl concentrations were correlated with outdoor carbonyls in three kindergartens. The health risk assessment showed that hazard indexes (HIs) HIs of non-cancer risks from PBDEs and DPs were all lower than 0.08, whilst non-cancer HIs of carbonyl compounds ranged from 0.77 to 1.85 indoors and from 0.50 to 0.97 outdoors. The human intake of PBDEs and DP through inhalation of PM_2.5 accounted for 78% to 92% of the total intake. The cancer hazard quotients (HQs) of formaldehyde ranged from 4.5E-05 to 2.1E-04 indoors and from 1.9E-05 to 6.2E-05 outdoors. In general, the indoor air pollution in the five Hong Kong kindergartens might present adverse effects to children, although different schools showed distinct pollution levels, so indoor air quality might be improved through artificial measures. The data will be useful to developing a feasible management protocol for indoor environments.

Relationship between legacy and emerging organic pollutants in Antarctic seabirds and their foraging ecology as shown by δ13C and δ15N

Foraging ecology and the marine regions exploited by Antarctic seabirds outside of breeding strongly influence their exposure to persistent organic pollutants (POPs). However, relationships between them are largely unknown, an important knowledge gap given that many species are capital breeders and POPs may be deleterious to seabirds. This study investigates the relationship between Antarctic seabird foraging ecology (measured by δ¹³C and δ¹⁵N) and POPs accumulated in their eggs prior to breeding. Organochlorinated pesticides, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and dechlorane plus (DP) were measured in eggs of chinstrap, Adélie, and gentoo penguins (Pygoscelis antarctica, P. adeliae, P. papua), as well as south polar skua (Catharacta maccormicki), sampled on King George Island. Total POP levels were as follows: skua (3210±3330ng/g lipid weight)>chinstrap (338±128ng/g)>Adélie (287±43.3ng/g)>gentoo (252±49.4ng/g). Trophic position and pre-breeding foraging sites were important in explaining POP accumulation patterns across species. The most recalcitrant compounds were preferentially accumulated in skuas, occupying one trophic level above penguins. In contrast, their Antarctic endemism, coupled with influence from cold condensation of pollutants, likely contributed to penguins exhibiting higher concentrations of more volatile compounds (e.g., hexachlorobenzene, PCB-28 and -52) than skuas. Regional differences in penguin pre-breeding foraging areas did not significantly affect their POP burdens, whereas the trans-equatorial migration and foraging sites of skuas were strongly reflected in their pollutant profiles, especially for PBDEs and DPs. Overall, our results provide new insights on migratory birds as biovectors of POPs, including non-globally regulated compounds such as DP, from northern regions to Antarctica.

PBDEs and Dechlorane Plus in the environment of Guiyu, Southeast China: A historical location for E-waste recycling (2004, 2014)

Polybrominated diphenyl ethers (PBDEs, tri-to hepta-BDEs) and Dechlorane Plus (DP) in multiple samples (soil, sediment, road dust, and PM_2.5 particles) in historical locations of our previous work in Guiyu (electronic-waste recycling town) in southeastern China were investigated in 2014. Ten years later, PBDEs and DP were detected in 100% of the samples. Ʃ_3-7PBDEs were still relatively great, ranging from 1.2 × 10¹ to 2.1 × 10³ ng/g dry weight (dw) in soil, 2.1 to 3.2 × 10³ ng/g dw in sediment, 1.0 × 10¹ to 1.1 × 10⁴ ng/g dw in road dust, which were a little less than or close to those measured in 2004. However, Ʃ_3-7PBDEs in PM_2.5 (5.0 × 10² to 8.4 × 10² pg/m³) were significantly lower in 2014. BDE-47, -99, -153, and -183 were predominant congeners, which were also predominant PBDEs reported in Guiyu (2006-2008). Greater proportions of lesser-brominated BDEs were predominant in PM_2.5 than other samples. DP was detected in 100% of the samples collected with high levels. Total syn-DP and anti-DP concentrations were 3.8 to 2.1 × 10³ ng/g dw in soil, 1.1 × 10³ to 7.2 × 10³ ng/g dw in sediment, 1.4 × 10¹ to 1.1 × 10³ ng/g dw in road dust, and 1.8 × 10² and 1.7 × 10² pg/m³ in PM_2.5. Most of the fractions of anti-DP (f_anti) (70%-80%) were consistent among samples. The health risk assessment showed that hazard indexes (HIs) of PBDEs or DPs for child or adult were all lower than 0.16.

Neurodevelopmental toxicity assessments of alkyl phenanthrene and Dechlorane Plus co-exposure in zebrafish

Alkyl phenanthrene (A-Phen) and Dechlorane Plus (DP) are ubiquitous environmental pollutants that widely co-exist in the environment. It has been established that both A-Phen and DP elicit neurotoxicity, but the potential interactive toxicity of these contaminants is not well-known. To determine whether a mixture of A-Phen and DP would exhibit interactive effects on neurodevelopment, we co-exposed 3-methylphenanthrene (3-MP), a representative of A-Phen, with DP. Our results illustrated that exposure to 5 or 20 μg/L 3-MP alone or in combination with 60 μg/L DP caused neurobehavioral anomalies in zebrafish. In accordance with the behavioral deficits, 3-MP alone or co-exposed with DP significantly decreased axonal growth of secondary motoneurons, altered intracellular Ca²⁺ homeostasis and induced cell apoptosis in the muscle of zebrafish. Additionally, 3-MP alone or co-exposed with DP significantly increased reactive oxygen species (ROS) and the mRNA levels of apoptosis-related genes. These findings indicate that 3-MP alone or co-exposed with DP induces neurobehavioral deficits through the combined effects on neuronal connectivity and muscle function. Chemical analysis revealed significant increases in 3-MP and DP bioaccumulation in zebrafish co-exposed with 3-MP and DP. Elevated bioaccumulation resulting from mixture exposure may represent a significant contribution of the synergistic effects observed in combined chemical exposure.

Halogenated flame retardants in building and decoration materials in China: Implications for human exposure via inhalation and dust ingestion

In this study, polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), and dechlorane plus (DPs) were analyzed in seven categories of building and decoration materials. The total concentrations of analyzed FRs ranged from 1.19 ng/g (diatomite powder) to 9532 ng/g (expanded polystyrene panel). Relatively high concentrations were detected in foam samples and PVC materials, followed by sealing materials, boards, wallpaper, paints, and wall decoration powders. BDE209 was the most detected compound with the highest concentrations in almost all materials, followed by decabromodiphenyl ethane (DBDPE), which was consistent with their productions and consumptions in China. The estimated PBDE concentrations in air and dust based on material concentration and emission rate were comparable with those detected in real samples. Adult and infant exposures via inhalation and dust ingestion were assessed. The estimated exposures to BDE209 via dust ingestion were 1.36 and 0.12 ng/(kg bw d), which were 19- and 4-fold higher than those via inhalation for infants and adults, respectively. This suggested that dust ingestion was a significant pathway of human BDE209 exposure, especially for infants. For the other PBDE congeners (∑₇PBDEs), the estimated exposures via inhalation were 2.60 and 1.32 ng/(kg bw d) for infants and adults, respectively. Despite the low estimated human exposures to PBDEs compared to the oral reference doses, the exposure associated with building and decoration materials still requires more attention because of the potential risks from other exposure pathways and undetected FRs in those materials.

Environmental risk assessment of perfluoroalkyl substances and halogenated flame retardants released from biosolids-amended soils

Biosolid application is considered a sustainable management tool as it positively contributes to recycle nutrients and to improve soil properties and fertility. Nevertheless, this waste management technique involves an important input source of emerging organic pollutants in soil. To evaluate the environmental potential risk related to perfluoroalkyl substances (PFASs) and halogenated flame retardants (HFRs) due to the biosolid application to soil, a quantitative ecotoxicological risk assessment was conducted. The analyte concentrations were employed to perform an estimation of the exposure levels to contaminants in the receiving media, defining predicted environmental concentrations (PECs) for terrestrial and aquatic compartments (PEC_soil, PEC_water, PEC_sed) and for secondary poisoning via the terrestrial and aquatic food chain (PEC_{oral, predator (T)}, PEC_{oral, predator (Aq)}). The risk characterization ratios (RCRs) were calculated based in the comparison of the PEC values obtained with concentrations with no effect (PNECs) on terrestrial and aquatic ecosystems. Based on the chosen scenarios and experimental conditions, no environmental risk of PFASs and HFRs released from biosolid amended soils to different environmental compartments was detected (RCR_soil, RCR_{oral, worm}, RCR_water, RCR_sed and RCR_{oral, fish} were below 1 in all cases). Besides, the potential health risk of PFASs and HFRs to local people who live in the scenario studied and are fed on horticultural crops grown in biosolid amended soil was also below 1, indicating that the risk is not considered significant to human health in the conditions studied. This approach provides a first insight of the risks relative to biosolid amendments to further research based on fieldwork risk assessment.

Dechlorane Plus induces oxidative stress and decreases cyclooxygenase activity in the blue mussel

Dechlorane Plus (DP) is a chlorinated flame retardant used mainly in electrical wire and cable coating, computer connectors, and plastic roofing materials. Concentrations of DP (syn and anti isomers) are increasingly being reported in aquatic ecosystems worldwide. However, there is exceedingly little information on the exposure-related toxicity of DP in aquatic organisms, especially in bivalves. The objective of this study was to investigate the in vivo and in vitro effects of DP exposure on histopathology, lipid peroxidation (LPO) levels, cyclooxygenase (COX) activity, phagocytosis capacity and efficiency, and DNA strand breakage in the blue mussel (Mytilus edulis) following a 29days exposure (0.001, 0.01, 0.1 and 1.0μg DP/L). Blue mussels accumulated DP in muscle and digestive gland in a dose-dependent manner. LPO levels in gills were found to increase by 82% and 67% at the 0.01 and 1.0μg DP/L doses, respectively, while COX activity in gills decreased by 44% at the 1μg/L dose. No histopathological lesion was found in gonads following DP exposure. Moreover, no change in hemocyte DNA strand breakage, phagocytosis rate, and viability was observed following DP exposure. Present study showed that toxicity of DP may occur primarily via oxidative stress in the blue mussel and potentially other bivalves, and that gills represent the most responsive tissue to this exposure.

Investigating the presence of emerging and legacy POPs in European domestic air

Presence of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and dechlorane plus (DP) were evaluated in indoor domestic air from four European countries (Belgium, Italy, Spain and Portugal). The main pollutants were hexachlorohexanes (sum of α-, β- and γ-HCH; ΣHCHs) and ΣPCBs (sum of PCB-28, 52, 101, 118, 138, 153 and 180), with median concentrations of 366 and 306 pg/m³, respectively. By decreasing order came hexachlorobenzene (HCB; 130 pg/m³), ΣDDXs (sum of DDTs, DDEs and DDDs; 94.4 pg/m³), ΣPBDEs (sum of BDE-17, 28, 47, 66, 99, 100, 153, 154, 183, 206, 207 and 209; 6.08 pg/m³) and DP (0.30 pg/m³). Lower ΣPCBs and ΣDDXs levels were found at Portuguese homes compared to Belgian, Italian and Spanish households. Italian samples presented also lower ΣHCHs concentrations while Spanish homes revealed higher HCB and BDE-209 indoor air concentrations than those obtained in the other countries. ΣHCHs, ΣDDXs and ΣPBDE levels mirrored lindane, dicofol and Penta-, DecaBDE use, respectively. The influence of building characteristics, surroundings and inhabitants habits on pollutant air concentrations was investigated. Data generated were used to conduct a human exposure assessment for toddlers and adults with median (P50) and upper (P95) concentrations. Results indicated that health risk posed by inhalation of ΣPCBs, ΣHCHs, ΣDDXs, HCB, ΣPBDEs and DP were 2 to 5 orders of magnitude lower than oral Reference Dose (RfD) values, and 90 (PCB-28) and 12 (γ-HCH) times lower than Minimal Risk Levels (MRLs) for toddlers at the worst case scenario.

Dechloranes in lichens from the southeast Tibetan Plateau: Evidence of long-range atmospheric transport

Dechloranes (Decs) have been recently found to occur widely in the environment even in the remote polar regions. However, the understanding of their environmental fate is rather limited. The Tibetan Plateau (TP) may be an important indicator region to study the long-range atmospheric transport and their fates of these emerging contaminants since it has very limited local sources. In the present study, Dechlorane plus (DP), Dechlorane 602 (Dec 602), Dechlorane 603 (Dec 603) and Dechlorane 604 (Dec 604) were analyzed in lichen samples from the southeast TP. The results showed that only DP and Dec 602 were detected, with a detection frequency of 89% and 100%, respectively. The average concentrations (dry weight) of ΣDP and Dec 602 were 318 pg g(-1) (20-1132 pg g(-1)) and 167 pg g(-1) (27-843 pg g(-1)), respectively. The DP concentration in this study was much higher than those in moss from the remote Ny-Ålesund, Arctic. The concentrations of Dec 602 were found to generally increase with increasing altitude, while DP concentrations seemingly showed an opposite altitudinal trend along the mountain slopes. No stereoselective accumulation or transformation of anti-DP and syn-DP was observed in lichens and the altitudinal behavior of the two isomers was similar. This research documented that Decs are prone to undergo LRAT and cold-trapping by the mountains in the southeast TP.

Polybrominated diphenyl ethers, dechlorane plus, and polychlorinated biphenyls in tree bark near the upper Yellow River, China

Willow tree bark samples from urban and rural sites in Inner Mongolia, Ningxia Province, and Gansu Province, in the Yellow River basin, were analyzed for polybrominated diphenyl ethers (PBDEs), dechlorane plus (DP), and dioxin-like polychlorinated biphenyls (DL-PCBs) to compare their relative levels in air in these areas (i.e., treating bark as a passive air sampler). No difference was found between the pollutant concentrations in Salix matsudana and Salix babylonica bark samples. The mean concentrations of the total PBDEs, DP, and total DL-PCBs were 13000 ± 6400, 46 ± 44, and 26 ± 17 pg/g dry weight, respectively, with urban samples containing much higher concentrations (19000 ± 5700 pg/g, 51 ± 27 pg/g, and 37 ± 29 pg/g dry wt in PBDEs, DP, and DL-PCBs, respectively) than rural samples (10000 ± 5200 pg/g, 45 ± 53 pg/g, 22 ± 9 pg/g dry wt). A strong positive correlation between PBDEs and DP was found in all of the samples (r=0.712, p=0.006), but correlations between PCBs and the other pollutants were only found in the rural samples. The total DL-PCB concentration in the tree bark correlated with population density.

Occurrence, composition, source, and regional distribution of halogenated flame retardants and polybrominated dibenzo-p-dioxin/dibenzofuran in the soils of Guiyu, China

Guiyu, China, is well-known for the crude disposal of electronic waste (EW) and severe persistent organic pollutants (POPs). Therefore, in this study, the occurrence, composition, and source of polybrominated diphenyl ethers (PBDEs), 2,2',4,4',5,5'-hexabromobiphenyl (BB153), some novel brominated flame retardants (NBFRs), Dechlorane Plus (DP) and polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs) in farmland soils covering Guiyu were studied. In EW disposal area soils, PBDEs were the most abundant FRs, with concentrations of 13-1014 ng g^-1. The primary PBDE sources were technical Penta- and Deca-BDE mixtures in northern and southern Guiyu, respectively. The levels of BB153 were relatively low, possibly because it has been banned in the 1970s. The concentrations of hexabromobenzene (HBB) were 0.048-3.3 ng g^-1, while pentabromoethylbenzene (PBEB) was almost not detected in the soils. Two alternatives to commercial PBDEs, decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), were the primary NBFRs, with concentrations of 1.8-153 ng g^-1 and 0.43-15 ng g^-1, respectively. DP was another primary FR, with concentrations of 0.57-146 ng g^-1. Moreover, syn-DP and anti-DP isomers were not stereoselectively decomposed during the EW disposal process and were therefore present in their original fractions in the soils. The levels of PBDD/Fs in EW disposal area soils were 2.5-17 pg TEQ g^-1. 1,2,3,4,6,7,8-HpBDF and OBDF were the dominant congeners, mainly derived from processing, pyrolysis and combustion of BFRs. The regional distribution of pollutants was shown to be related to the disposal manner of EW, with their open thermal disposal tending to release more highly brominated compounds such as BDE209, DBDPE, and 1,2,3,4,6,7,8-HpBDF. Additionally, some riverbank sites were heavily polluted because of nearby point sources, downwind Simapu (SMP) town without EW disposal activity was also contaminated by these pollutants.

Short-term fasts increase levels of halogenated flame retardants in tissues of a wild incubating bird

Many species are adapted for fasting during parts of their life cycle. For species undergoing extreme fasts, lipid stores are mobilized and accumulated contaminants can be released to exert toxicological effects. However, it is unknown if short-term fasting events may have a similar effect. The objective of this study was to determine if short successive fasts are related to contaminant levels in liver and plasma of birds. In ring-billed gulls (Larus delawarensis), both members of the pair alternate between incubating the nest for several hours (during which they fast) and foraging, making them a useful model for examining this question. Birds were equipped with miniature data loggers recording time and GPS position for two days to determine the proportion and duration of time birds spent in these two activities. Liver and plasma samples were collected, and halogenated flame retardants (HFRs) (PBDEs and dechlorane plus) and organochlorines (OCs) (PCBs, DDTs, and chlordane-related compounds) were determined. Most birds (79%) exhibited plasma lipid content below 1%, indicating a likely fasted state, and plasma lipid percent declined with the number of hours spent at the nest site. The more time birds spent at their nest site, the higher were their plasma and liver concentrations of HFRs. However, body condition indices were unrelated to either the amount of time birds fasted at the nest site or contaminant levels, suggesting that lipid mobilization might not have been severe enough to affect overall body condition of birds and to explain the relationship between fasting and HFR concentrations. A similar relationship between fasting and OC levels was not observed, suggesting that different factors are affecting short-term temporal variations in concentrations of these two classes of contaminants. This study demonstrates that short fasts can be related to increased internal contaminant exposure in birds and that this may be a confounding factor in research and monitoring involving tissue concentrations of HFRs in wild birds.

Polybrominated diphenyl ethers (PBDEs) and dechlorane plus (DP) in a conventional wastewater treatment plant (WWTP) in Shanghai: seasonal variations and potential sources

Wastewater treatment plants (WWTPs) are considered an important medium for the transport and transformation of organic pollutants, such as polybrominated diphenyl ethers (PBDEs) and dechlorane plus (DP). However, limited data on PBDEs and no data on DP were available regarding wastewater and sludge from China, especially in Shanghai, one of the most developed cities in China. This study examined the occurrence of PBDEs and DP in a conventional WWTP in Shanghai for one year. The levels of the total PBDEs in the influent and dewatered sludge ranged from 5.31 to 27.9 ng/L and 31.0 to 99.5 ng/g, respectively, which were at the low end of the global range. DP was reported in wastewater with a mean concentration of 0.46 ng/L (range: 0.05 to 1.40 ng/L) and sludge contained DP in the range of 1.1 to 2.0 ng/g. For both PBDEs and DP, there were no significant seasonal variations observed in the four seasons. Indoor dust and outdoor air could be two main sources of PBDEs and DP in the WWTP. In both the influent and sewage sludge, BDE-209 was the most abundant congener, with contributions to the total PBDE levels ranging from 52.9 to 82.6% and 82.7 to 84.0%, respectively. The fraction of anti-DP was consistently higher than that of syn-DP, and the average of fsyn ranged from 0.16 to 0.33, which fell in the range of two commercial DP mixtures. The annual releases of PBDEs and DP via sewage sludge from WWTPs in Shanghai were estimated to be 6,370 g and 164.8 g, respectively. The fate and risk of these compounds after being released into the environment require further research. To the best of our knowledge, this study is the first to report on the occurrence of DP in wastewater.

Flame retardants and their associations with thyroid hormone-related variables in northern fulmars from the Faroe Islands

Flame retardants (FRs) are widely reported in tissues of seabirds including birds sampled from remote areas. There is evidence that FRs can disrupt the hypothalamic-pituitary-thyroid (HPT) axis in seabirds, although information is limited on thyroid-related mechanisms and effects. This study investigated the associations between concentrations of polybrominated diphenyl ethers (PBDEs) and other FRs, and changes in the HPT axis in northern fulmars (Fulmarus glacialis) from the Faroe Islands (North Atlantic). Plasma concentrations of thyroid hormones (THs), hepatic deiodinase type 1 (D1) activity, and transcription of selected TH-related genes in liver were used as markers of HPT axis changes. Liver concentrations of a certain PBDE congeners and other FRs including pentabromoethylbenzene (PBEB), dechlorane 602 (Dec-602), and dechlorane plus (DP) were associated with changes in thyroid status. Specifically, liver PBDE, PBEB and Dec-602 concentrations were associated with plasma TH levels (free thyroxine [FT₄] and total triiodothyronine [TT₃]). Liver DP concentrations were positively correlated with the TT₄:FT₄ ratios and mRNA levels of UDP-glucuronyltransferase-1, while those of PBEB were negatively associated with TT₄:TT₃ ratios and D1 activity. D1 activity was also positively associated with the tri-, tetra- and hexa-BDE congeners. Moreover, transcription of ABCC2, a hepatic TH transporter, was associated with certain liver PBDE concentrations. Although PBDEs and other FRs may be potential inhibitors of D1 activity, only a few of the targeted FRs had modest associations with hepatic D1 activity. Regardless, the relationships reported herein indicated that exposure to moderate levels of FRs can be associated with thyroid axis perturbation at the molecular/biochemical levels in this North Atlantic seabird species.

Changes in plasma biochemistry in breeding ring-billed gulls: Effects of anthropogenic habitat use and contaminant exposure

Gulls (Larids) have become successful at exploiting anthropogenic areas for foraging. However, little is known on the health implications of using anthropogenic habitats and on the associated exposure to environmental contaminants, particularly with respect to plasma biochemistry that is routinely used to diagnose physiological disorders and diseases. The objective of the present study was to investigate the effects of anthropogenic habitat use and exposure to ubiquitous halogenated flame retardants (HFRs) on plasma biochemistry of urban-breeding ring-billed gulls (Larus delawarensis) from one of the largest colonies in North America. Miniature GPS dataloggers were used to characterize foraging habitat use of individual gulls (n = 39) at the regional scale (urban, waste management facilities, agricultural fields, and St. Lawrence River) in the Montreal area (QC, Canada), and plasma was analyzed for a suite of biochemical measures (waste products, lipids, glucose, ions, proteins, and enzymes) and HFRs. Several confounding biological and environmental variables were also assessed including sex, body condition, time spent fasting while incubating, plasma thyroid hormone levels, time of day, capture date, and ambient temperature. As ring-billed gulls (males and females combined) spent more time foraging in urban areas, their plasma concentrations of cholesterol, albumin and activity of alkaline phosphatase increased significantly. Moreover, as the gulls spent more time foraging in agricultural fields, their plasma concentrations of phosphorous and activity of aspartate aminotransferase increased significantly. Only the activity of aspartate aminotransferase was significantly positively related to plasma HFR concentrations (PBDEs and dechlorane-related compounds). Time spent fasting while incubating, plasma thyroid hormone levels, body condition, time of day, and capture date were significantly related to certain plasma biochemical measures. The present results suggest that both the use of anthropogenic habitats for foraging and exposure to HFRs may affect the plasma biochemistry of ring-billed gulls breeding in the densely-populated Montreal area, suggesting potential adverse health effects for avian wildlife living in highly urbanized environments.

Occurrence and ecological risks of brominated flame retardants and dechlorane plus in sediments from the Pearl River Estuary and Daya Bay, South China

Considering the phasing-out of polybrominated diphenyl ethers (PBDEs), environmental concerns of PBDE alternatives and dechlorane plus (DP) are rising. Accordingly, this study investigates occurrence and ecological risks of PBDEs, PBDE alternatives and DPs in sediments of two littoral regions, the Pearl River Estuary (PRE) and Daya Bay (DYB), in southern China. Total PBDEs concentrations in surface sediments of the PRE and DYB were in the range (mean) of 0.30-28.7 (8.71) and 0.29-43.4 (6.05) ng/g dw, respectively. DP levels in surface sediments of the PRE (0.004-0.27 ng/g dw) were significantly higher than those in the DYB (0.005-0.24 ng/g dw) (p < 0.05). BDE 209 was the predominant component, followed by DBDPE, exhibiting regional variations in BFRs usage. Vertical profiles of BFRs and DP in the PRE and DYB sediment cores exhibited clear anthropogenic influences. Risk quotients suggest critical ecological risks of tetra-, penta- and deca-BDE congeners in all the surface sediments.

Halogenated flame retardants in tree samples applied as bioindicators for atmospheric pollution

Coniferous shoots and deciduous tree leaf samples from 10 sites in Germany were taken in 2015 or 2016 within the German Environmental Specimen Bank sampling program and analysed for 24 polybrominated biphenyl ethers (PBDEs) and 19 additional halogenated flame retardants (HFRs). At one site, additional historic samples dating back till 2003 were also investigated. Samples were Soxhlet-extracted, cleaned-up by a non-destructive multi-step procedure involving gel permeation chromatography, and detected by GC-API-MS/MS as well as GC-MS. Besides PBDEs as classical HFRs, emerging HFRs such as Dechlorane Plus, DPTE, DBDPE, or ATE were region-wide observed demonstrating their widespread occurrence in the atmosphere. Highest concentrations in recent samples were found for DBDPE (<230-2760 pg g^-1 dry weight (dw)) followed by DPTE (91-1540 pg g^-1 dw), BDE209 (<156-461 pg g^-1 dw), and BDE47 (<27-505 pg g^-1 dw) or DP (31-122 pg g^-1 dw). The overall uniform and widespread distribution as well as similar HFR levels and composition profiles observed in recent conifer shoots and corresponding deciduous tree leaves from the same area indicate a prolonged medium to long-range transport as sources. Furthermore, it is demonstrated that both tree types are generally suitable bioindicators for atmospheric pollution with HFRs, although accumulation may vary depending on HFR properties and accumulation period. The historic samples showed decreasing PBDE levels whereas no clear trend could be observed for other investigated HFRs at this site.

Uptake, depuration, bioaccumulation, and selective enrichment of dechlorane plus in common carp (Cyprinus carpio)

Dechlorane plus (DP) is a chlorinated flame retardant with high production volume (HPV) and is widely used in our daily necessities. In the present study, a laboratory-scale microcosm was built up to simulate the uptake, depuration, bioaccumulation, and stereoselective enrichment of DP in a lower concentration and equilibration condition. Common carp (Cyprinus carpio) were used for 32 days exposure and 32 days depuration. The concentration ratios of syn-DP to total DP (f_syn values) in fish examined were lower than that in commercial products. Rate constants of uptake (k_S) and elimination (k_e) for the syn- and anti-DP were calculated using a first-order kinetic model. The uptake rate constants of syn- and anti-DP were 0.63 and 0.89 day^-1, respectively. The depuration rate constants of syn-DP (0.11 day^-1) were similar to anti-DP (0.096 day^-1), suggesting that anti-DP is absorbed faster than syn-DP by common carp. The estimated bioconcentration factors for both syn-DP (5700 L/kg) and anti-DP (9300 L/kg) were higher than the bioconcentration hazard criteria outlined in the Stockholm Convention, suggesting the bioconcentration potential to aquatic organisms for DP.

Source, fate and budget of Dechlorane Plus (DP) in a typical semi-closed sea, China

Dechlorane Plus (DP), which has severe effects on marine ecosystems, has been proposed for listing under the Stockholm Convention as a persistent organic pollutant (POPs). This study was the first comprehensive investigation of the concentration and fate of DP in the Bohai Sea (BS) based on determination of river estuary water, river estuary sediment, surface seawater, bottom seawater, and sea sediments samples. The highest water DP levels were found in river estuary in Tianjin in North China due to the huge usage of DP in recent years, and spatial distribution analysis indicates it was mainly affected by regional high urbanization and emission of E-waste. The spatial distribution of DP in the BS was mainly affected by a combination of coastal hydrodynamics and land anthropogenic activities. On the basis of multi-box mass balance, simulations of DP in seawater showed an increase from 2014 to 2025, before leveling off at 184 pg L ^-1 by a constant DP input to the BS. Riverine discharge almost contributed to the total input (∼99%) and dominated the DP levels in the BS. Degradation of DP accounted for 55.3% and 78.1% of total DP output in seawater and sediment, respectively, indicating that degradation mainly affected decline of DP in the environment.

Temporal trends in classical and alternative flame retardants in bird eggs from Doñana Natural Space and surrounding areas (south-western Spain) between 1999 and 2013

Several halogenated flame retardants were detected in black kite, white stork and greater flamingo unborn eggs from Doñana Natural Space (Spain) collected in 1999, 2003, 2011 and 2013. The main components of Penta-BDE commercial mixture (BDE-47, -99 and -100) showed a decrease in the studied time interval, concurring with the ban of this mixture in the European Union (EU) in 2006. On the other hand, BDE-209, the main component of Deca-BDE mixture showed a clear trend in black kites but further monitoring is needed since its production ceased at the end of 2013. Besides, even if Dechlorane Plus (DP) was proposed by the EU as an alternative to BDE-209 no time trends were observed. Furthermore, total concentrations of PBDEs (classical FRs) are still higher than concentrations of hexabromocyclododecane (HBCD) and alternative FRs halogenated norbornenes (HNs), which are theoretically substitutes of the already banned PBDEs.

Recent findings of halogenated flame retardants (HFR) in the German and Polar environment

To get an overview about distribution, levels and temporal trends of polybrominated diphenyl ethers (PBDE) and halogenated flame retardants (HFR) of emerging concern, different types of environmental samples archived in the German Environment Specimen Bank as well as fish filet samples from the Arctic (n = 13) and Antarctica (n = 5) were analysed for 43 substances (24 PBDE, 19 HFR) using a multi-column clean-up and GC-API-MS/MS or GC-MS. Sample types were herring gull egg (n = 3), blue mussel (n = 3) and eelpout filet (n = 3) from the German North- and Baltic Sea, bream filet (n = 7), zebra mussel (n = 6) and suspended particulate matter (SPM, n = 7) from German freshwater ecosystems as well as tree leaves (n = 9)/shoots (n = 10), soil (n = 4), earthworm (n = 4) and deer liver (n = 7) as representatives of German terrestrial ecosystems. PBDE and emerging HFR were present in each investigated matrices from Germany and Polar regions showing their widespread distribution. The presence in Arctic and Antarctic fish samples confirms their long-range transport potential. Average concentrations of total emerging HFR were highest in SPM (26 ng g^-1 dry weight (dw)), zebra mussel (10 ng g^-1 dw) and herring gull egg (2.6 ng g^-1 dw). Lowest levels were measured in fish filet samples from Antarctica (0.02 ng g^-1 dw). Average total PBDE concentrations were highest in bream filet (154 ng g^-1), herring gull egg (61 ng g^-1 dw), SPM (21 ng g^-1 dw), and zebra mussel 18 (ng g^-1) and lowest in deer liver (0.04 ng g^-1 dw). The patterns of non-fauna terrestrial samples (leaves, shoots, soil) as well as SPM were dominated by DBDPE and BDE209. Elevated proportions of DPTE and in most cases the absence of DBDPE characterized all fauna samples with the exception of Polar samples. Overall, emerging HFR appeared to be less bioaccumulative than PBDE. Temporal trends were generally decreasing with few exceptions such as DBDPE.