Diphenyl Ether Congeners Research Articles

Occurrence and health risk of legacy and emerging halogenated flame retardants in seafood from the Beibu Gulf, China

Due to high industrialization and urbanization, the offshore areas may be contaminated with halogenated flame retardants (HFRs) by human activities. Seafood is a significant part of the human diet, especially for people living near the coast, and has been identified as a significant source of human exposure to HFRs. This study investigated the occurrence, composition, and dietary exposure to HFRs in seafood by analyzing samples (fish, shrimp, crab, and mollusk) collected from three provinces surrounding the Beibu Gulf, China. The concentrations of Σ14PBDEs ranged from 1.36 to 145.1 ng/g dry weight (dw), with Portunus trituberculatus and Harpiosquilla harpax having the highest and lowest concentrations, respectively. Among the polybrominated diphenyl ethers (PBDEs) congeners analyzed, BDE 209 was the most abundant. The levels of decabromodiphenyl ethane (DBDPE), 1, 2-bis (2, 4, 6 tribromophenoxy) ethane (BTBPE), dechlorane plus (DP), and bis (2-ethylhexyl) 2, 3, 4, 5-tetrabromophthalate (TBPH) in seafood varied from not detected (ND) to 92.6 ng/g dw, ND to 696 ng/g dw, ND to 13.2 ng/g dw, and ND to 0.49 ng/g dw, respectively. The concentrations of the emerging HFRs (EHFRs) found in fish were significantly higher than in other bio-samples. Moreover, DBDPE was identified as the primary EHFR across all seafood samples. Fish and mollusks were the primary sources of ΣEHFRs and ΣPBDEs for overall local seafood consumption. According to the health risk assessment of PBDEs, the consumption of seafood in the Beibu Gulf does not pose a significant non-carcinogenic health risk to the residents.

A decade of data and hundreds of analytes: Legacy and emerging chemicals in North American herring gull plasma

Between 2010 and 2021, 199 herring gull serum samples were collected from Lake Michigan, Lake Huron, and Lake Erie, including two Areas of Concern: Saginaw Bay and the River Raisin. They were analyzed for 21 polybrominated diphenyl ether congeners, 10 non-PBDE flame retardants, 85 polychlorinated biphenyls, 17 legacy organochlorine pesticides, and 36 per- and polyfluoroalkyl substances. Σ36PFAS, Σ85PCB, Σ21PBDE, and Σ17Pesticide concentrations comprised 41–74%, 17–50%, 3–4%, and 5–9% of the total concentration, respectively. Median concentrations of the chemical groups ranged from 81.5 to 129 ng/g ww for PFAS, 26.3–158 ng/g ww for PCBs, 4.26–8.89 ng/g ww for PBDEs, and 8.08–23.0 ng/g ww for pesticides. The regional concentrations of all four classes of compounds are significantly decreasing when sites are combined with halving times of 11.3 ± 4.8, 8.2 ± 4.3, 5.9 ± 3.1, and 8.3 ± 4.2 years for the Penta-BDE mixture, ΣDDTs, Σ85PCBs and Σ36PFAS, respectively. These results suggest that, while PFAS has emerged as the dominant group of chemicals in the plasma, legacy pollutants continue to represent a threat to herring gulls and wildlife in the Great Lakes basin. PCBs were the largest contributors to the chemical load in plasma of birds whose colonies are located near the River Raisin, and continue to pose a threat to herring gulls within the two Areas of Concern.

Polybrominated diphenyl ether contamination in sediments from rivers in the western Niger Delta of Nigeria

This study investigated the concentrations of 39 polybrominated diphenyl ether (PBDE) congeners in sediments from three rivers in the western Niger Delta of Nigeria that have been affected by pollution from urbanization and industrial activities. The Σ39 PBDE concentrations in sediments from these rivers ranged from 0.29 to 95.5, 5.15 to 121, and 0.73 to 66.1 ng g−1 for the Afiesere (AR), Edor (ER), and Okpare Rivers (OR), respectively. The homologue distribution patterns indicated the prominence of tetra- and penta-BDE congeners in sediments from these rivers. The ecological risk assessment results showed that the penta-BDEs were the primary source of risk to sediment-dwelling organisms in these rivers. However, the human health risk assessment indicated negligible risks for exposure of both adults and children to PBDEs in these sediments. The source apportionment suggests that the PBDE contamination in these river sediments was derived from long-distance migration, debromination of highly brominated congeners, and commercial penta-BDEs. These results reflect the use of penta-BDE formulations in this region rather than octa- and deca-BDE formulations.

Glucocorticoid hormones in relation to environmental exposure to bisphenols and multiclass pesticides among middle aged-women: Results from hair analysis

Bisphenols and pesticides have been shown to alter circulating glucocorticoids levels in animals, but there is limited human data. Moreover, measurements from biological fluids may not be able to reflect long-term status of non-persistent pollutants and glucocorticoids due to the high variability in their levels. Using hair analysis, we examined the associations between glucocorticoid hormones and environmental exposure to multi-class organic pollutants among a healthy female population aged 25–45 years old. Concentrations of four glucocorticoids, four polychlorinated biphenyl congeners (PCBs), seven polybrominated diphenyl ether congeners (PBDEs), two bisphenols and 140 pesticides and their metabolites were measured in hair samples collected from 196 Chinese women living in urban areas. Due to the low detection frequency of some pollutants, associations were explored only on 54 pollutants, i.e. PCB 180, bisphenol A, bisphenol S and 51 pesticides and their metabolites. Using stability-based Lasso regression, there were associations of cortisol, tetrahydrocortisol, cortisone, and tetrahydrocortisone with 14, 10, 13 and 17 biomarkers of exposure to pollutants, respectively, with bisphenol S, p,p’-dichlorodiphenyldichloroethylene, diethyl phosphate, 3,5,6-trichloro-2-pyridinol, thiamethoxam, imidacloprid, fipronil, tebuconazole, trifluralin, pyraclostrobin and 1-(3,4-dichlorophenyl)-3-methylurea being associated with at least three of the four hormones. There were also associations between cortisone/cortisol molar ratio and pollutants, namely dimethyl phosphate, 3-methyl-4-nitrophenol, carbofuran, λ-cyhalothrin, permethrin, fipronil, flusilazole, prometryn and fenuron. Some of these relationships were confirmed by single-pollutant linear regression analyses. Overall, our results suggest that background level of exposure to bisphenols and currently used pesticides may interfere with the glucocorticoid homeostasis in healthy women.

HBM4EU E-waste study: Assessing persistent organic pollutants in blood, silicone wristbands, and settled dust among E-waste recycling workers in Europe

E-waste recycling is an increasingly important activity that contributes to reducing the burden of end-of-life electronic and electrical apparatus and allows for the EU's transition to a circular economy. This study investigated the exposure levels of selected persistent organic pollutants (POPs) in workers from e-waste recycling facilities across Europe.The concentrations of seven polychlorinated biphenyls (PCBs) and eight polybrominated diphenyl ethers (PBDEs) congeners were measured by GC-MS. Workers were categorized into five groups based on the type of e-waste handled and two control groups. Generalized linear models were used to assess the determinants of exposure levels among workers. POPs levels were also assessed in dust and silicone wristbands (SWB) and compared with serum.Four PCB congeners (CB 118, 138, 153, and 180) were frequently detected in serum regardless of worker's category. With the exception of CB 118, all tested PCBs were significantly higher in workers compared to the control group. Controls working in the same company as occupationally exposed (Within control group), also displayed higher levels of serum CB 180 than non-industrial controls with no known exposures to these chemicals (Outwith controls) (p < 0.05). BDE 209 was the most prevalent POP in settled dust (16 μg/g) and SWB (220 ng/WB). Spearman correlation revealed moderate to strong positive correlations between SWB and dust. Increased age and the number of years smoked cigarettes were key determinants for workers exposure. Estimated daily intake through dust ingestion revealed that ΣPCB was higher for both the 50th (0.03 ng/kg bw/day) and 95th (0.09 ng/kg bw/day) percentile exposure scenarios compared to values reported for the general population.This study is one of the first to address the occupational exposure to PCBs and PBDEs in Europe among e-waste workers through biomonitoring combined with analysis of settled dust and SWB. Our findings suggest that e-waste workers may face elevated PCB exposure and that appropriate exposure assessments are needed to establish effective mitigation strategies.

Association between brominated flame retardants and risk of endocrine-related cancer: A systematic review and meta-analysis

BackgroundThe incidence of endocrine-related cancer, which includes tumors in major endocrine glands such as the breast, thyroid, pituitary, and prostate, has been increasing year by year. Various studies have indicated that brominated flame retardants (BFRs) are neurotoxic, endocrine-toxic, reproductive-toxic, and even carcinogenic. However, the epidemiological relationship between BFR exposure and endocrine-related cancer risk remains unclear. MethodsWe searched the PubMed, Google Scholar, and Web of Science databases for articles evaluating the association between BFR exposure and endocrine-related cancer risk. The odds ratio (OR) and its corresponding 95% confidence interval (95% CI) were used to assess the association. Statistical heterogeneity among studies was assessed with the Q-test and I2 statistics. Begg’s test was performed to evaluate the publication bias. ResultsWe collected 15 studies, including 6 nested case-control and 9 case-control studies, with 3468 cases and 4187 controls. These studies assessed the risk of breast cancer, thyroid cancer, and endocrine-related cancers in relation to BFR levels. Our findings indicate a significant association between BFR exposure in adipose tissue and an increased risk of breast cancer. However, this association was not observed for thyroid cancer. Generally, BFR exposure appears to elevate the risk of endocrine-related cancers, with a notable increase in risk linked to higher levels of BDE-28, a specific polybrominated diphenyl ether congener. ConclusionsIn conclusion, although this meta-analysis has several limitations, our results suggest that BFR exposure is a significant risk factor for breast cancer, and low-brominated BDE-28 exposure could significantly increase the risk of endocrine-related cancers. Further research is essential to clarify the potential causal relationships between BFRs and endocrine-related cancers, and their carcinogenic mechanisms.

MEASUREMENT OF PERSISTENT ORGANIC POLLUTANTS, PERFLUORINATED COMPOUNDS, AND TOXIC METALS IN THE BLOOD OF HUMBOLDT PENGUINS (SPHENISCUS HUMBOLDTI) AT PUNTA SAN JUAN, PERU USING DRIED BLOOD SPOTS.

The Humboldt penguin (Spheniscus humboldti) population at the Punta San Juan Marine Protected Area in Peru is considered critical to the long-term sustainability of this endangered species in Peru. Exposure of the rookery to environmental toxicants is a mounting concern because of regional growth of industries and human populations. Whole blood samples were collected from 30 free-ranging penguins in 2011 as part of a broader population health monitoring program. Dried blood spots (DBS) containing 50 µl of blood were prepared and analyzed to assess exposure to five groups of environmental contaminants. Concentrations of elements arsenic, cadmium, iron, lead, mercury, selenium, and thallium were analyzed using inductively coupled plasma mass spectrometry. Persistent organic pollutant concentrations were measured using gas chromatography-tandem mass spectrometry to analyze organochlorine pesticides (OCP; p,p'-DDT, p,p'-DDE, β-hexachlorocyclohexane, t-nonachlor, and oxychlordane), polychlorinated biphenyls (congeners 138 and 153), and polybrominated flame retardants (polybrominated biphenyl-153 and polybrominated diphenyl ether congeners 47 and 99). Per- and polyfluoroalkyl substances, including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid were measured using liquid chromatography-tandem mass spectrometry. Results revealed low levels of exposure to these selected contaminants, at levels not considered to be of concern for wildlife health. DBS methodology was considered effective in a field-based setting for quantification of whole blood concentrations of environmental contaminants in penguins.

Exposure to persistent organic pollutants in newborn dried blood spots and childhood acute myeloid leukemia

Acute myeloid leukemia (AML) is a rare malignancy representing 15–20% of all leukemia diagnoses among children. Maternal exposure to persistent organic pollutants is suggestive of increased risk for childhood AML based on existing evidence. We aimed to evaluate the relationship between persistent organic pollutants and childhood AML using newborn dried bloodspots (DBS) from the Michigan BioTrust for Health. We obtained data on AML cases diagnosed prior to 15 years of age (n = 130) and controls (n = 130) matched to cases on week of birth from the Michigan Department of Health and Human Services. We quantified levels of dichlorodiphenyldichloroethylene (p,p’-DDE), hexachlorobenzene (HCB), and polybrominated diphenyl ether congener 47 (BDE-47) in newborn DBS. We also evaluated other organochlorine pesticides, polychlorinated biphenyls, polybrominated biphenyl congener 153, and polybrominated diphenyl ethers, though these were not further evaluated as >60% of observations were above the limit of detection for these chemicals. To evaluate the association between each chemical and AML, we used multivariable conditional logistic regression. In our multivariable model of HCB adjusted for month of birth, maternal age at delivery, and area poverty, we observed no association with AML (Odds Ratio [OR] per interquartile range increase: 1.17, 95% CI: 0.80, 1.69). For p,p’-DDE, ORs were significantly lower for those exposed to the highest tertile of p,’p-DDE (≥0.29 pg/mL, OR: 0.32, 95% CI: 0.11, 0.95) compared to the first tertile (<0.09 pg/mL). We observed no statistically significant associations between HCB and BDE-47 and AML. We observed a reduced odds of exposure to p,’p-DDE and an increased, though imprecise, odds of exposure to HCB among AML cases compared to controls. Future studies would benefit from a larger sample of AML patients and pooling newborn DBS across multiple states to allow for additional variability in exposures and evaluation of AML subtypes, which may have differing etiology.

Organohalogenated contaminants in multiple life stages of the Pacific lamprey (Entosphenus tridentatus), Oregon, USA

Pacific lamprey (Entosphenus tridentatus) are ecologically and culturally important anadromous animals native to the West Coast of the United States. Pacific lamprey populations are in decline, and contaminants may be a contributing factor. Between 2017 and 2021, three life stages of Pacific lamprey and collocated sediment samples were collected in Oregon (larval lamprey, sediment, and returning adult lamprey) and off the coast of Oregon and Washington (ocean juvenile lamprey). Tissue and sediment samples were analyzed for 56 organohalogenated compounds that included legacy pesticides, current use pesticides, polybrominated diphenyl ether congeners, and polychlorinated biphenyl congeners. Organohalogenated compounds were detected in all three Pacific lamprey life stages. The organohalogenated compounds detected in collocated sediment and larval lamprey samples were generally dissimilar, and compounds detected in larval lamprey indicate potential point sources along the rivers. Ocean-caught juvenile lamprey had significantly higher lipid contents than returning adult lamprey, but lipid content and concentrations of select compounds were not strongly correlated. Concentrations of select compounds detected in both ocean juvenile and returning adult lamprey were either not significantly different or were higher in returning adult lamprey. Concentrations of some compounds in returning adult lamprey—which are consumed by Indigenous peoples—exceeded state and national human health consumption thresholds. Collaboration among Tribes and public-sector agencies helped make this study successful.

Polybrominated diphenyl ethers and polycyclic aromatic hydrocarbons in dust from different indoor environments in Zagreb, Croatia: Levels and human exposure assessment.

The present study reports for the first time the levels of 7 polybrominated diphenyl ether (PBDE) congeners and 11 polycyclic aromatic hydrocarbons (PAH) measured in dust samples collected in 10 kindergartens, 11 workplaces, and 25 cars from Zagreb, Croatia. ΣPBDEs mass fractions were 3.11-14.42, <LOD-313.75, and 0.6-5666.98 ng g-1 dust, while ΣPAHs were 244.9-833.0, 230.5-5632.7, and 395.6-12114.8ng g-1 dust in kindergartens, workplaces, and cars, respectively. In the central case scenario, dust from homes contributed to the intake of PBDEs and PAHs the most, while for PBDEs in the worst-case scenario, the intake through car dust prevailed. Carcinogenic and non-carcinogenic risks were assessed for PAHs and PBDEs, respectively, for two age groups (adults and toddlers) and for professional drivers as a specific group. The hazard index for adults, toddlers, and professional drivers for PBDEs was less than 1 indicating that there is no significant risk of non-carcinogenic effects due to exposure to these chemicals. Total carcinogenic risk for PAHs was negligible for all groups in the central case scenario, but the Incremental Lifetime Cancer Risk values >10-6 in the worst-case scenario indicated a potential risk, especially for professional drivers. Also, in the cases of elevated contaminant levels, toddlers are susceptible to a higher risk, despite the short time they spend in cars.

Hazardous organic pollutants in indoor dust from elementary schools and kindergartens in Greece: Implications for children's health

Children spend a significant portion of their day in school, where they may be exposed to hazardous organic compounds accumulated in indoor dust. The aim of this study was to evaluate the concentrations of major hazardous organic contaminants in dust collected from kindergartens and elementary schools in Northern Greece (n = 20). The sum concentrations of 20 targeted polybrominated diphenyl ether congeners (∑20PBDEs) in dust varied from 58 ng g−1 to 1480 ng g−1, while the sum of 4 novel brominated fire retardants (∑4NBFRs) ranged from 28 ng g−1 to 555 ng g−1. Correspondingly, the sum concentrations of phthalate esters (∑9PAEs) ranged between 265 μg g−1 and 2120 μg g−1, while the sum of organophosphate esters (∑11OPEs) was found between 2890 ng g−1 and 16,100 ng g−1. Finally, the sum concentrations of polycyclic aromatic hydrocarbons (∑16PAHs) were found within in the range 212 ng g−1 and 6960 ng g−1. Exposure to indoor dust contaminant via inhalation, ingestion and dermal absorption was investigated for children and adults (teachers). Carcinogenic and non-carcinogenic risks were also estimated. Children's estimated intakes of individual hazardous chemicals via the three exposure routes, were lower than the available health-based reference values.

2, 2′, 4, 4′-tetrabromodiphenyl ether induces placental toxicity via activation of p38 MAPK signaling pathway in vivo and in vitro

2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47) is one of the most important polybrominated diphenyl ethers (PBDEs) congeners, and epidemiological studies have shown that it can cause adverse pregnancy outcomes. The aim of our study was to investigate the role of placental injury in BDE-47-induced adverse pregnancy outcomes through in vivo and in vitro models. From day 0.5 to day 16.5 of pregnancy of ICR mice, BDE-47 oral doses of 0, 25, 50 and 100mg/kg/day were administered. Immunohistochemical staining found that BDE-47 inhibited the expression of CD34 in mouse placenta, and ELISA results showed that BDE-47 reduced the levels of VEGF and PlGF in the serum of pregnant mice. Western blot assays found that the expression levels of VEGF-A and invasion-related factors were decreased in the placentas of BDE-47-treated group, which indicated that BDE-47 could impair placental angiogenesis. Furthermore, BDE-47 inhibited proliferation, increased apoptosis and autophagy, and activated p38 MAPK signaling pathway in mouse placental tissue. In vitro, HTR-8/SVneo cells were treated with 0, 5, 10, 20μM BDE-47 for 24h. Wound healing assays and Transwell assays showed that BDE-47 inhibited the migration and invasion ability of HTR-8/SVneo cells. We also found that BDE-47 inhibited the proliferation of HTR-8/SVneo cells and increased apoptosis and autophagy. BDE-47 activated p38 MAPK signaling pathway in HTR-8/SVneo cells, and inhibition of p38 MAPK signaling pathway in HTR-8/SVneo cells restored the effects caused by BDE-47. In conclusion, BDE-47 impairs placental angiogenesis by inhibiting cell migration and invasion, and induces placental toxicity by inhibiting proliferation, increasing apoptosis and autophagy. In vitro, activation of p38 MAPK signaling pathway is involved in the processes of placental injury by BDE-47.

Bidirectional regulation of BDE-47 on 3T3-L1 cell differentiation based on a restricted cubic spline model.

BDE-47 (2,2,4,4-tetrabromodiphenyl ether) is a polybrominated diphenyl ether (PBDE) congener, which has the characteristics of high biological detection rate, the highest content and strong biological toxicity, and is widely distributed in organisms. Many studies have found that BDE-47 may also be an environmental risk factor for metabolic diseases such as obesity, insulin resistance, type 2 diabetes, and hypertension. However, the way that PBDEs influence adipocyte differentiation remains unclear. The methylisobutylxanthine, dexamethasone, and insulin method was used to study the effect of BDE-47 on the differentiation of 3T3-L1 cells. The 3T3-L1 cells were exposed by different concentrations of BDE-47, and the effect of cell viability was detected at different stages. In addition, the lipid droplet aggregation of adipocytes was observed and the triglyceride (TG) levels in the cytoplasm were detected after differentiation. The relative mRNA expression levels of leptin, adiponectin, and PPARγ in cells were determined by RT-PCR, and differentially expressed genes were preliminarily screened by digital gene expression profile. Our study found that BDE-47 promoted the differentiation of 3T3-L1 cells. Restriction cubic spline analysis showed that BDE-47 bidirectionally. regulated the mRNA synthesis of TG, PPARγ, and leptin genes and the aggregation of lipid droplets. BDE-47 may induce adipocyte differentiation by activating PPARγ, resulting in the differential expression of genes related to the AMPK signaling pathway, insulin resistance, and other metabolic pathways. The highest and lowest-dose BDE-47 exposure groups had the greatest impact on adipocyte differentiation.

The concentration and biomagnification of PCBs and PBDEs across four trophic levels in a marine food web

Contracting Parties to the OSPAR Convention for the Protection of the Maine Environment of the North-East Atlantic are required to undertake monitoring and assessment of both inorganic and organic contaminants. There is a requirement to assess contaminants across different trophic levels on an ecosystem-specific basis. However, this is currently constrained by the availability of relevant samples to cover the full range of trophic levels. This study investigates the variability (inter- and intra-species variation) of the concentrations and distributions of thirty-two polychlorinated biphenyl (PCB) congeners and nine polybrominated diphenyl ether (PBDE) congeners in twenty-six species covering four trophic levels from different geographic locations around Scotland. Trophic magnification factors (TMFs) were calculated using a traditional method and a balanced method for both the ICES-7 PCBs and BDE47, to refine and improve the application of TMFs to assess and predict biomagnification risk to biota in the marine environment. There were clear differences in congener percentage distribution between sample categories and species, with differences influenced by physiological processes and eco-biological parameters. Trophic magnification was found to occur for the ICES-7 PCBs and BDE47 using the traditional method, with the highest degree of trophic magnification reported for CB52. An unbalanced dataset was found to influence the calculated TMF and in some cases, the overall conclusion of the trophic transfer of PCB and PBDE congeners. The balanced method is highly recommended for calculating TMFs to ensure that the TMF is a true indication of the biomagnification potential, particularly when conducting regional comparisons for which sampling requirements are difficult to achieve.

PBDEs Found in House Dust Impact Human Lung Epithelial Cell Homeostasis.

The toxicity of eight polybrominated diphenyl ethers (PBDEs) congeners detected in environmental and biological samples (BDE-28, -47, -99, -100, -153, -154, -183, and -209) was evaluated on the epithelial lung cells. Exposure to these PBDEs increased membrane disruption and a release of lactate dehydrogenase, accompanied by oxidative stress in cells through the formation of reactive oxygen species (ROS) and a decrease in mitochondrial membrane potential. Interestingly, some of the tested PBDEs increased apoptotic markers as well. For several congeners, the observed toxicity was time dependent, meaning that even smaller concentrations of these compounds will have negative effects over time. Such time-dependent toxicity was also confirmed for cell treatment with a real house dust sample extract. This could be indicative with regard to the constant exposure to a mixture of PBDE congeners through different pathways in the organism and thereby presenting a risk for human health. As such, our findings point to the importance of further studies on the negative effects of PBDEs to understand their mechanism of action in detail.

Temporal Trends of Persistent Organic Pollutants in Sarasota Bay Common Bottlenose Dolphins (Tursiops truncatus)

Legacy persistent organic pollutants (POPs) were measured in blubber samples collected from 196 common bottlenose dolphins (Tursiops truncatus) from 2000 to 2016 in the Sarasota Bay, Florida, ecosystem. Legacy POPs included polychlorinated biphenyl congeners (ΣPCB; sum of 37 congeners or congener groups), dichloro-diphenyl-trichloroethane (DDT) and transformation products (ΣDDT), chlordane and related compounds (ΣChlor), mirex, polybrominated diphenyl ether congeners (ΣPBDE, sum of five congeners), dieldrin and hexachlorobenzene (HCB). All POP compounds or compound groups declined in dolphin blubber over the study period. POP classes declined at different rates within classifications (sex, adult or calf). For example, dieldrin decline in male dolphins was greatest (−13% per year) while HCB decline was lower (−6.3% per year). For individual POP classes, rates of decline depended on classification. For example, ΣPCB, the POP class present at the highest concentration relative to other POPs, declined at −8.4, −7.8, and −5.6% per year in adult females, adult males and calves, respectively. Overall POP declines were highest in adult males and lowest in calves. Declines in POP concentration with time based on individual dolphins resampled at different time points were consistent with declines calculated based on yearly or biennial cross-sections taken from 2000 through 2016. Overall rates of decline in Sarasota Bay bottlenose dolphins were like declines seen for Great Lakes fish and about twice the rate of decline observed in arctic temporal trend data sets. POP trends appear to have leveled off since 2009 in Sarasota Bay dolphins. For example, ΣPCBs in calves appear to have stabilized at 21 mg/kg lipid. Recent published work on delphinids with blubber concentrations spanning those observed in the present work suggest that levels of legacy POPs currently observed in Sarasota dolphins may suppress population growth. Results from this study confirm the need for continued monitoring of POPs in the Sarasota Bay bottlenose dolphin population to see if concentrations are continuing to fall or have indeed plateaued.

Comparative effects of oral exposure to 2, 4, 6-tribromophenol and decabromodiphenyl ether in Nile tilapia.

Flame retardants are compounds added to a high diversity of polymers used in electronics and furniture to decrease the risk of combustion. Decabromodiphenyl ether (BDE-209) is a polybrominated diphenyl ether (PBDE) congener still used worldwide, while 2, 4, 6-tribromophenol(TBP) is a PBDE metabolite used as a pesticide and flame retardant for wood conservation. These compounds have lipophilic properties and are easily bioaccumulated in the food chain. In the current study, the acute and chronic toxicity of BDE-209 and TBP was evaluated in Oreochromis niloticus through analyses of redox imbalance, neurotoxicity, and histopathological biomarkers after acute (24, 48, 72, and 96 h) and chronic (90 days) exposure to 0.5, 5, and 50 ng/g of the polybrominated compounds. The results showed effects on glutathione S-transferase(GST) activity and damage to biomolecules in both acute and chronic exposures. Liver histopathology and the ultrastructure of hepatocytes revealed alterations and damage in individuals from both experiments, but only BDE-209 led to neurotoxic effects. The current study revealed new endpoints related to polybrominated compounds in fish, highlighting the need to review the risk of exposure to biota.

Polybrominated diphenyl ethers and the multi-element profile of house dust in Croatia: Indoor sources, influencing factors of their accumulation and health risk assessment for humans

Given the large amount of time people spend indoors today, human exposure to indoor contaminants causes increasing public health concerns. The present study reports for the first time the levels of 7 polybrominated diphenyl ether (PBDE) congeners, and 18 trace elements measured in dust samples collected in 68 households from Zagreb, Croatia. Based on the obtained data from dust analysis and the questionnaire on the house characteristics and habits of the residents, we aimed to assess the possible indoor sources of PBDEs/elements, and the associated health risks.Mass concentrations of ΣPBDE ranged from 0.16 and 200.09 ng g−1 dust (median 4.19 ng g−1 dust). The most frequently detected congeners were BDE-99 and BDE-183 found in >88% of samples, while for trace elements, Al, Fe, Zn, Mn and Cu were found at the highest concentrations (enumerated in the descending order). The regression analysis indicated that renovation, number of residents and hours spent using electronic devices are significant predictors for determining PBDE dust concentrations, while the house age, and the house area were identified as the most important contributors for most trace elements. Our health risk assessment considering dust ingestion and dermal absorption of analyzed dust indicated that no adverse health effects are expected in toddlers and adults from exposure to PBDEs or trace elements in house dust. However, calculating the worst case exposure scenario based on the maximum measured concentrations and high dust intake rates, it was estimated that there is a risk of potential adverse health effects for Co (HI > 1). Even though the cases of high exposure to toxic elements from dust are sporadic, and not common among the general population, this exposure scenario should be included whenever assessing the background exposure of children.

Legacy brominated flame retardants in human milk from the general population in Beijing, China: Biomonitoring, temporal trends from 2011 to 2018, and nursing infant's exposure assessment

Three kinds of legacy brominated flame retardants (BFRs), including eight polybrominated diphenyl ether (PBDE) congeners, tetrabromobisphenol A (TBBPA), and three hexabromocyclododecane (HBCDD) isomers, were analyzed in 105 human milk samples collected in 2018 from Beijing, China. The tested BFRs all showed high detection frequencies, and HBCDD was the most abundant BFR, with a median level of 7.64 × 103 pg/g lipid, followed by BDE-153 (389 pg/g lipid), BDE-209 (283 pg/g lipid), and TBBPA (271 pg/g lipid). By comparing the results of the present study with those of our previous Beijing human milk surveys conducted in 2014 and 2011, the contamination of TBBPA and HBCDD increased steadily from 2011 to 2018, whereas that of PBDEs decreased sharply during this period. Our results suggested that the production and consumption of BFRs in China have shifted from PBDEs to other FRs. Education level and the consumption of animal-derived foods such as eggs and meat were identified as major influencing factors for some BFRs. For nursing infants, the median levels of lower bound BFR daily intake via human milk ingestion ranged from 4.62 × 10−2 ng/kg bw/day for BDE-154 to 30.6 ng/kg bw/day for HBCDD. The daily intake of most BFRs by breastfeeding is unlikely to pose significant health risks for Beijing nursing infants. However, the minimum margin of exposure (MOE) of HBCDD was below its threshold value, which indicated that its daily intake might raise health concerns for some breastfed infants.

Fate of four Different Classes of Chemicals Under Aerobic and Anaerobic Conditions in Biological Wastewater Treatment

The removal mechanisms and extent of degradation of 28 chemicals (triclosan, fifteen polycyclic aromatic hydrocarbons, four estrogens, and eight polybrominated diphenyl ether congeners) in different biological treatment systems [activated sludge, up-flow anaerobic sludge blanket reactor (UASB) and waste stabilization pond (WSP)] was investigated to provide insights into the limits of engineered biological treatment systems. This was done through degradation experiments with inhibition and abiotic controls in static reactors under aerobic and anaerobic conditions. Estrogens showed higher first order degradation rates (0.1129 h−1) under aerobic conditions with activated sludge inocula followed by low molecular weight (LMW) PAHs (0.0171 h−1), triclosan (0.0072 h−1), middle (MMW) (0.0054 h−1) and high molecular weight PAHs (HMW) (0.0033 h−1). The same trend was observed under aerobic conditions with a facultative inoculum from a WSP, although at a much slower rate. Biodegradation was the major removal mechanism for these chemicals in the activated sludge and WSP WWTPs surveyed. Photodegradation of these chemicals was also observed and varied across the group of chemicals (estrogens (light rate = 0.4296 d−1; dark = 0.3900 d−1) degraded faster under light conditions while reverse was the case for triclosan (light rate = 0.0566 d−1; dark = 0.1752 d−1). Additionally, all the chemicals were resistant to anaerobic degradation with UASB sludge, which implies that their removal in the UASB of the surveyed WWTP was most likely via sorption onto solids. Importantly, the first order degradation rate determined in this study was used to estimate predicted effluent concentrations (PECs). The PECs showed good agreement with the measured effluent concentrations from a previous study for these treatment systems.