Legacy [e.g., brominated- (BFRs)] and alternative [e.g., organophosphate- (OPFRs) and nitrogenous- (NFRs)] flame retardants have a propensity to migrate out of consumer products, and thus are dispersed in indoor microenvironments. In this study, simultaneous presence of 11 BFRs, 18 OPFRs and 11 NFRs were measured in house dust collected from Tianjin, China. OPFRs were found at the highest concentrations, with a median value of 3200 ng/g, followed by NFRs (2600) and BFRs (1600). Tris(2-butoxyethyl) phosphate (median: 1800 ng/g), melamine (1100), and BDE-209 (870) were the top three most abundant chemicals in the respective groups. Location-specific patterns of flame retardant concentrations were found with 30%, 20% and 10% of samples were predominated by OPFRs, NFRs and BFRs, respectively, and the remaining samples contained by two or more of the chemical groups occurring concurrently. Network and cluster analysis results indicated the existence of multiple sources of flame retardants in the indoor microenvironment. Estimated human daily intakes via indoor dust ingestion were approximately several tens of ng/kg bw/day and were below their respective reference dose values. Our results indicate widespread occurrence of multiple flame retardant families in indoor dust and suggest need for continued monitoring and efforts to reduce exposures through dust ingestion.

1,2-dibromo-4-(1,2-dibromoethyl)-cyclohexane (DBE-DBCH) is a brominated flame retardant used in commercial and industrial applications. The use of DBE-DBCH containing products has resulted in an increased release into the environment. However, limited information is available on the long-term effects of DBE-DBCH and its effects in aquatic invertebrates. Thus, the present study was aimed at determining how DBE-DBCH diastereomers (αβ and γδ) affects aquatic invertebrates using Daphnia magna as a model organism. Survival, reproduction, feeding, swimming behavior and toxicogenomic responses to environmental relevant concentrations of DBE-DBCH were analyzed. Chronic exposure to DBE-DBCH resulted in decreased lifespan, and reduced fecundity. Expression of genes involved in reproductive processes, vtg1 and jhe, were also inhibited. DBE-DBCH also induced hypoxia by inhibiting the transcription of genes involved in heme biosynthesis and oxygen transport. Furthermore, DBE-DBCH also inhibited feeding resulting in emptiness of the alimentary canal. Increased expression of the stress response biomarkers was observed following DBE-DBCH exposure. In addition, DBE-DBCH diastereomers also altered the swimming behavior of Daphnia magna. The present study demonstrates that DBE-DBCH cause multiple deleterious effects on Daphnia magna, including effects on reproduction and hormonal systems. These endocrine disrupting effects are in agreement with effects observed on vertebrates. Furthermore, as is the case in vertebrates, DBE-DBCH γδ exerted stronger effects than DBE-DBCH αβ on Daphnia magna. This indicate that DBE-DBCH γδ has properties making it more toxic to all so far studied animals than DBE-DBCH αβ.

The emergence of organophosphorus flame retardants and the efficient removal from aquatic environments have aroused increasing concerns. The Urea functionalized Fe₃O₄@LDH (Urea-Fe₃O₄@LDH) was prepared and used to adsorb triphenyl phosphate (tphp) for the first time. The tphp adsorption capacity was up to 589 mg g⁻¹, and the adsorption rate reached 49.9 mg g⁻¹ min⁻¹. Moreover, the influences of various environmental factors (pH, ionic strength and organic matter) on the tphp adsorption on the Urea-Fe₃O₄@LDH were investigated. The initial pH of the solution significantly affected the tphp adsorption, whereas the ionic strength and HA slightly affected the adsorption. The main adsorption mechanism was attributed to electrostatic interaction and π-π interaction. We believe that urea is one of excellent functional groups for the tphp adsorption removal and the materials with urea groups as the adsorbents exhibit good prospects in the future.

Assessing the fate of both legacy and newer persistent organic pollutants (POPs) is an ongoing challenge. Top predators, including seabirds, are effective monitors of POPs because they forage over a range of marine habitats, integrating signals over space and time. However, migration patterns can make unravelling contaminant sources, and potentially assessments of the effectiveness of regulations, challenging if chemicals are acquired at distant sites. In 2014, we fitted geolocators on ancient murrelets (Synthliboramphus antiqueus) at four colonies on the Pacific Coast of Canada to obtain movement data throughout an annual cycle. All birds underwent a post-breeding moult in the Bering Sea. Around one-third then returned to overwinter on the British Columbia (BC) coast while the rest migrated to overwinter in waters along the north Asian coast. Such a stark difference in migration destination provided an opportunity to examine the influence of wintering location on contaminant signals. In summer 2015, we collected blood samples from returned geo-tagged birds and analyzed them for a suite of contaminants, including polybrominated diphenyl ethers (PBDEs), non-PBDE halogenated flame retardants, perfluoroalkyl substances (PFASs), organochlorines, and mercury. Feathers were also collected and analyzed for stable isotopes (δ¹³C, δ¹⁵N, and δ³⁴S). We found no significant differences in blood concentrations of any contaminant between murrelets from the two different overwinter areas, a result that indicates relatively rapid clearance of POPs accumulated during winter. Spatial variation in diet (i.e., δ¹³C) was associated with both BDE-47 and -99 concentrations. However, individual variation in trophic level had little influence on concentrations of any other examined contaminants. Thus, blood from these murrelets is a good indicator of recent, local contaminants, as most signals appear independent of overwintering location.

Tris(2-chloroethyl) phosphate (TCEP) is a widely found emerging pollutant due to its heavy usage as a flame retardant. It is chemically stable and is very difficult to removal from water. The goal of this study was to explore whether iron monosulfide (FeS) can be used for reductive transformation of TCEP as FeS can react with a variety of halogenated organic contaminants. We used batch reactor systems to quantify the transformation reactions in the absence and presence of cetyltrimethylammonium bromide (CTAB, a common surfactant in aquatic environments). The results showed that, in the presence of CTAB (100 mg L⁻¹), FeS exhibited much greater reactivity towards TCEP as 93% of initial TCEP had been transformed within 14 d of reaction. In the absence of CTAB, it required 710 d of reaction to achieve 97.3% reduction of initial TCEP. The enhancement of CTAB on TCEP transformation rate could be due to the facts that CTAB could stabilize FeS suspension against aggregation, protect FeS from rapid oxidation, and increase surface adsorption of TCEP on FeS. XPS analysis showed that both Fe(II) and S(-II) species on the FeS surface were involved in the reductive transformation of TCEP. Analysis of transformation products revealed that TCEP was reductively transformed into bis(2-chloroethyl) phosphate (BCEP), Cl⁻ and C₂H₄. These findings showed that FeS may play an important role in the reductive transformation of TCEP when TCEP coexisting with CTAB in aquatic environments.

Decabromodiphenyl ether (DecaBDE) is a brominated flame retardant belonging to the group of polybrominated diphenyl ethers. DecaBDE has been widely used for various applications, such as plastics, textiles, and building and construction materials. Limited information on DecaBDE production and usage inventory has been elaborated, however. Therefore, this work aimed to produce a preliminary emissions inventory of DecaBDE in mainland China by estimating production and consumption amounts of DecaBDE, and characterizing its emission factors during production and usage, based on industrial investigation and theoretical prediction. It was indicated that the total production of DecaBDE reached 464.68 thousand metric tons (kt), of which 62.72 kt were exported, since the beginning of its production. Shandong and Jiangsu provinces dominate the production, with proportions of 77.95% and 18.45%, respectively. The production stage releases most of the DecaBDE to the atmosphere, with an emissions factor of 23 ± 1.9 kg/t, followed by 20 ± 0.9 kg/t DecaBDE to waste water and 16 ± 1.0 kg/t DecaBDE as solid residue. DecaBDE emissions in the consumption stage—namely the plastic production process—are 0.17 ± 0.06–0.23 ± 0.08 kg DecaBDE to the atmosphere and 1.72 ± 0.58–2.29 ± 0.77 kg DecaBDE to solid residue, for each metric ton of plastic produced. The total annual DecaBDE emissions to waste water are 93.98–1140.9 mg—negligible. The results showed that the sources of DecaBDE environmental pollution are its manufacturing and flame-retardant plastic modification plants, which are easily overlooked by both the government and the public. Yet DecaBDE emissions elimination and the environmentally sound management of the DecaBDE waste generated from these two processes are crucial for environmental protection.

Endocrine-disrupting chemicals (EDCs) are compounds that interfere with the expression, synthesis, and activity of hormones in organisms. They are released into the environment from flame retardants and products containing plasticizers. Persistent pesticides, such as dichlorodiphenyltrichloroethane (DDT) and hexachlorobenzene, also disrupt the endocrine system through interaction with hormone receptors. Endogenous hormones, such as 17β-estradiol (E2), are released in the urine and feces of farm animals and seep into terrestrial and aquatic ecosystems through sewage. Pigs are widely used as animal models to determine the effects of EDCs because they are physiologically, biochemically, and histologically similar to humans. EDCs primarily disrupt the reproductive and nervous systems of pigs. Moreover, embryonic development during the prenatal and early postnatal periods is particularly sensitive to EDCs. Mycotoxins, such as zearalenone, are food contaminants that alter hormonal activities in pigs. Mycotoxins also alter the innate immune system in pigs, making them vulnerable to diseases. It has been reported that farm animals are exposed to various types of EDCs, which accumulate in tissues, such as those of gonads, livers, and intestines. There is a lack of an integrated understanding of the impact of EDCs on porcine reproduction and development. Thus, this article aims to provide a comprehensive review of literature regarding the effects of EDCs in pigs.

Aryl phosphorus-containing flame retardants (aryl-PFRs) have been frequently detected with increasingly used worldwide as one of alternatives for brominated flame retardants. However, information on their adverse effects on human health and ecosystem is insufficient, with limited study on their molecular mode of action in vitro. In this study, the cytotoxicity, DNA damage, mitochondrial impairment and the involved molecular mechanisms of certain frequently detectable aryl-PFRs, including 2-ethylhexyldiphenyl phosphate (EHDPP), methyl diphenyl phosphate (MDPP), bisphenol-A bis (diphenyl phosphate) (BDP), isodecyl diphenyl phosphate (IDPP), cresyl diphenyl phosphate (CDP) and the structurally similar and widely used organophosphorus pesticide chlorpyrifos (CPF), were evaluated in A549 cells using high-content screening (HCS) system. Aryl-PFRs showed different lethal concentration 50 (LC50) values ranging from 97.94 to 546.85 μM in A549 cells using CCK-8 assay. EHDPP, IDPP, CDP, MDPP and CPF demonstrated an ability to induce DNA damage, evidenced by increased DNA content and S phase-reducing cell cycle arrest effect using fluorophore dye cocktail assay. Additionally, the selected aryl-PFRs induced mitochondrial impairment by the increasing mitochondrial mass and decreasing mitochondrial membrane potential. Moreover, BDP, MDPP, and CDP, which contain short alkyl chains showed their potential oxidative stress with intracellular ROS and mitochondrial superoxide overproduction from an initially relatively low concentration. Additionally, based on the promotion of firefly luminescence in p53-transfected A549 cells, p53 activation was found to be involved in aryl-PFRs-induced DNA damage. Further real-time PCR results showed that all selected aryl-PFRs triggered p53/p21/gadd45β-, and p53/p21/mdm2-mediated cell cycle pathways, and the p53/bax mediated apoptosis pathway to induce DNA damage and cytotoxic effects. These results suggest that aryl-PFRs (e.g., BDP, MDPP, CDP) cause oxidative stress-mediated DNA damage and mitochondrial impairment, and p53-dependent pathway was involved in the aryl-PFRs-induced DNA damage and cell cycle arrest. In conclusion, this study improves the understanding of PFRs-induced adverse outcomes and the involved molecular mechanism.

Ninety-eight soil samples were collected from farmland soils from Beijing-Tianjin-Hebei core area, Northern China, where agricultural lands were subjected to contamination from intense urban and industrial activities. Twelve organophosphates flame retardants (OPFRs) were analyzed with total soil concentrations ranging from 0.543 μg/kg to 54.9 μg/kg. Chlorinated OPFRs were dominating at mean level of 3.64 μg/kg and Tris(2-chloroisopropyl) phosphate contributed the most (mean 3.36 ± 5.61 μg/kg, 98.0%). Tris(2-ethylhexyl) phosphate was fully detected at levels of 0.041–1.95 μg/kg. Generally, tris(2-butoxyethyl) phosphate and triphenyl phosphate contributed the most to alkyl- (53.6%) and aryl-OPFRs (54.3%), respectively. The levels of ∑OPFRs close to the core urban areas were significantly higher than those from background sites. The occurrence and fate of OPFRs in soil were significantly associated with total organic carbon content and mostly with fine soil particles (<0.005 mm), and a transfer potential from the atmosphere was predicted with logKSA values. Comparable soil levels with poly brominated diphenyl ethers s in other studies suggested that the contamination of OPFRs occurred in farmland soil with an increasing trend but currently showed no significant environmental risk based on risk quotient estimation (<1). This investigation warrants further study on behaviors of OPFRs in a soil system and a continual monitoring for their risk assessment.

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.