Polybrominated Biphenyls Research Articles

Polyphenols Regulate the Activity of Endocrine-Disrupting Chemicals, Having Both Positive and Negative Effects.

Endocrine-disrupting chemicals (EDCs) are chemical substances that can interfere with any hormone action. They are categorized according to origin and use, such as industrial chemicals like polychlorinated biphenyls (PCBs) and polybrominated biphenyls (PBBs), plastics like bisphenol A (BPA), plasticizers like phthalates, pesticides like dichlorodiphenyltrichloroethane (DDT), fungicides like vinclozolin, and pharmaceuticals like diethylstilbestrol (DES). Natural EDCs, such as phytoestrogens, are present in the diet of both humans and animals. Polyphenols are a large group of natural compounds derived from plants and are found in beverages and food. They are grouped based on their chemical structure into flavonoids and nonflavonoids and are reported to have many beneficial effects on health, including, but not limited to, anticancer, antioxidant, and anti-inflammatory effects. Moreover, polyphenols have both pro- and antioxidant characteristics, and due to their antioxidant and anti-inflammatory potential, they presumably have a protective effect against damage induced by EDCs. However, polyphenols may act as EDCs. In this review, we report that polyphenols regulate the activity of EDCs, having both positive and negative effects. Hence, a better understanding of the associations between EDCs and polyphenols will allow the establishment of improved approaches to protect human health from EDCs.

Variation profiles, formation mechanisms, and emission risks of brominated flame retardant compounds during cement kiln co-processing of hexabromocyclododecane-containing waste

Cement kiln co-processing technique has been suggested as a promising disposal method for hexabromocyclododecane (HBCD)-containing construction wastes. However, concerns persist regarding the potential emissions of secondary brominated flame retardant (BFR) compounds. To address this, we conducted both field and laboratory experiments to elucidate the emission characteristics and formation mechanisms of BFRs during the co-processing of HBCD-containing waste in cement kilns. In the field experiments, which examined a range of HBCD disposal dosages from 0 to 400 kg/day, the concentrations of new brominated flame retardants (NBFRs), polybrominated diphenyl ethers (PBDEs), and polybrominated biphenyls (PBBs) in the stack gas were 0.57–0.80, 0.68–51.56, 0.62–1.79 ng/Nm3, respectively. Over 77 % of the emitted BFRs can be sequestered within solid materials. Further laboratory experiments revealed that the alkaline substances present in cement kilns can absorb HBr thus inhibiting the formation of BFRs. The transformation mechanisms from HBCDs to BFRs were further explored to involve processes including structural re-arrangement, de novo synthesis, and precursor formation. Furthermore, the national annual emission risk associated with the disposal of HBCD-containing construction wastes via cement kilns has been assessed. The findings of our study furnish a critical scientific basis for the development of strategies for managing HBCD-containing waste in the future.

Temporal trends (1972-2017) and spatial differences of persistent halogenated aromatic hydrocarbons in osprey eggs in Finland.

Time trends and regional differences of polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), DDTs, polybrominated biphenyls (PBBs) and polybrominated diphenylethers (BDEs) were studied in unhatched osprey eggs collected by bird ringers in 1972-2017 from four areas in Finland. Two study areas were from Baltic Sea, Northern Quark and Finnish Archipelago Sea, while the two others were inland lake areas, eutrophicated Lake Vanajanselkä affected by industrial emissions, and Pristine SW Lake Area. The highest concentrations of most compound groups were in Lake Vanajanselkä consistent with high emissions, the predominance of bream as a prey, and higher concentrations in bream compared to other prey fish. Concentrations of all chlorinated compounds decreased significantly in all study areas. Average annual decreases were ∑PCDD/F 2.3-4.9%, ∑PCB 2.2-4.2%, ∑PCN 2.6-7.0% and ∑DDT 7.1-9.5%, primarily in line with decreased levels in prey fish. From 1972 PBBs and BDEs increased significantly until 1990s declining rapidly thereafter. PCDD/F congener profile was dominated by 2,3,4,7,8-PeCDF, except in Lake Vanajanselkä by 1,2,3,6,7,8-HxCDD. PCB congener profile was dominated by PCB 153 in all study areas, followed by PCB 180 and PCB 138. Among dioxin-like compounds PCBs contributed 82%, PCDDs 14% and PCDFs 4% to toxic equivalent quantity (∑TEQ). PCB 126 contributed most to ∑TEQ, followed by 1,2,3,7,8-PeCDD. BDE 47 being the dominant BDE congener, followed by BDE 100. ∑DDT concentrations were relatively similar across all study areas, with DDE contributing about 90%. Productivity of chicks per active nest was significantly decreased in Lake Vanajanselkä, and the likely explanation is embryotoxicity of dioxin-like compounds. It is plausible that dioxin-like compounds influenced embryonic survival among highly exposed ospreys prior to 2010, especially in Lake Vanajanselkä and Northern Quark. However, decreased survival due to DDE-induced eggshell thinning seems unlikely after 1985, and BDE levels were below those potentially causing adverse effects.

An in silico study on human carcinogenicity mechanism of polybrominated biphenyls exposure

Polybrominated biphenyls (PBBs) are associated with an increased risk of thyroid cancer; however, relevant mechanistic studies are lacking. In this study, we investigated the mechanisms underlying PBB-induced human thyroid cancer. Molecular docking and molecular dynamics methods were employed to investigate the metabolism of PBBs by the cytochrome P450 enzyme under aryl hydrocarbon receptor mediation into mono- and di-hydroxylated metabolites. This was taken as the molecular initiation event. Subsequently, considering the interactions of PBBs and their metabolites with the thyroxine-binding globulin protein as key events, an adverse outcome pathway for thyroid cancer caused by PBBs exposure was constructed. Based on 2D quantitative structure activity relationship (2D-QSAR) models, the contribution of amino acid residues and binding energy were analyzed to understand the mechanism underlying human carcinogenicity (adverse effect) of PBBs. Hydrogen bond and van der Waals interactions were identified as key factors influencing the carcinogenic adverse outcome pathway of PBBs. Analysis of non-bonding forces revealed that PBBs and their hydroxylation products were predominantly bound to the thyroxine-binding globulin protein through hydrophobic and hydrogen bond interactions. The key amino acids involved in hydrophobic interactions were alanine 330, arginine 381 and lysine 270, and the key amino acids involved in hydrogen bond interactions were arginine 381 and lysine 270. This study provides valuable insights into the mechanisms underlying human health risk associated with PBBs exposure.

Exploring autism spectrum disorder (ASD) and attention deficit disorder (ADD/ADHD) in children exposed to polybrominated biphenyl.

Although the causes of attention-deficit/hyperactivity disorder (ADHD) and autism have not been identified, exposure to endocrine-disrupting chemicals, such as polybrominated biphenyl (PBB), during fetal development and early life has been suspected to impact neurological development. This study aims to investigate the association between prenatal and early life exposure to PBB and the development of ADHD and autism later in life. Data from the Michigan PBB Registry, a cohort of Michigan residents who had been exposed to PBB in a mass contamination event in 1973, was leveraged for this nested case-control analysis among two distinct samples: (1) Those who self-reported ADHD or autism diagnosis, and (2) mothers who reported their child's ADHD or autism diagnosis. PBB exposure was measured in participants of the PBB Registry, and the mother's PBB level was used in mother-reported analyses. Cases were matched with controls by sex and year of birth. Conditional logistic regression models were used to estimate the association between PBB level and case status. PBB levels were higher among those who were exposed in early life compared with those exposed in utero (geometric mean: 0.300 ng/ml vs. 0.016 ng/ml). Among women in this cohort, a higher than expected proportion of self-reported ADHD diagnosis (11.11%), compared with population estimates. PBB was not associated with ADHD or autism in either self-reported or mother-reported analyses. This study adds to the sparse literature about prenatal and early life exposure to PBB-153 and ADHD and autism. Future studies should examine potential effect modification by sex.

Exploring the impact of polystyrene microplastics on human health: unravelling the health implications of polystyrene microplastics (PS-MPs): a comprehensive study on cytotoxicity, reproductive health, human exposure, and exposure assessment.

This investigation explores the various impacts that polystyrene microplastics (PS-MPs) have on human health. As most of the plastic materials affect human health when they release leachable toxic substances that affect human health, this causes a negative effect that determines poor health conditions and leads to health hazards associated with plastic toxins routed in the human body, such as: Polychlorinated Biphenyls, Polybrominated Biphenyls etc. The study includes micro-plastic exposure assessment on testicular structure analysis, and cytotoxicity evaluations of different human cell types. The findings clarified the possible dangers of PS-MPs exposure from food, medications, and common products, emphasising the necessity of standard specimen handling procedures for precise biomonitoring.

Application of multicriteria decision analysis to assess the greenness of molecularly imprinted polymers synthesis components

The study applies multicriteria decision analysis (MCDA) to rank the components of molecularly imprinted polymers (MIPs) synthesis according to their greenness. The components are taken from papers that are describing synthesis of MIPs for persistent organic pollutants (POPs) sorbents. Functional monomers (n = 14), target/surrogate molecules (n = 10), porogens (n = 8), cross-linking agents (n = 8) and initiators (n = 4) are described with 10 criteria referring to their safety of application, toxicity, environmental persistence and bioaccumulability. The rankings are performed according to three scenarios, with the application of different weights. The ranking results give a specific guide on the selection of green synthesis components for polybrominated biphenyl ethers (PBDEs) as representatives of POPs, by identification of problematic and recommended chemicals. The results are useful in designing MIP synthesis protocols.

In-utero exposure to polybrominated biphenyl (PBB) and menstrual cycle function in adulthood

BackgroundThere is evidence that in-utero exposure to PBBs, and similar chemicals, are associated with several adverse reproductive health outcomes including altered pubertal timing. However, less is known about the effects of in-utero exposure to PBBs on menstrual cycle function and reproductive hormone levels in adulthood. MethodsFor this menstrual cycle study, we recruited reproductive-aged women in the Michigan PBB Registry who were not pregnant, lactating, or taking hormonal medications (2004–2014). A total of 41 women who were born after the PBB contamination incident (1973–1974) and were prenatally exposed to PBBs, were included in this analysis. We estimated in-utero PBB exposure using maternal serum PBB measurements taken after exposure and extrapolated to time of pregnancy using a PBB elimination model. Women were followed for up to 6 months during which they provided daily urine samples and completed daily diaries. The urine samples were assayed for estrone 3-glucuronide (E13G), pregnanediol 3-glucuronide (Pd3G), and follicle stimulating hormone (FSH). ResultsWomen in our study were, on average, 27.5 (SD:5.3) years old and contributed 4.9 (SD:1.9) menstrual cycles of follow-up. Compared to women with low in-utero PBB exposure (≤1 ppb), women with medium (>1.0–3.0 ppb) and high (>3.0 ppb) exposure had higher maximum 3-day mean Pd3G levels during the luteal phase. Specifically, the age- and creatinine-adjusted maximum 3-day mean luteal phase Pd3G levels (95% CI) in increasing categories of in-utero PBB exposure were 9.2 (4.6,13.9), 14.8 (11.6,18.0), and 16.1 (12.9,19.3) μg/mg creatinine. There were no meaningful differences in average cycle length, follicular or luteal phase cycle length, bleed length, or creatinine-adjusted E13G or FSH levels by category of in-utero PBB exposure. ConclusionHigher exposure to PBB in-utero was associated with increased progesterone levels across the luteal phase, however, most other menstrual cycle characteristics were largely unassociated with in-utero PBB exposure. Given our modest sample size, our results require cautious interpretation.

Persistent Halogenated Organic Pollutants in Deep-Water-Deposited Particulates from South China Sea.

POP data are limited in the marine environment; thus, this study aimed to investigate background persistent organic pollutant (POP) levels in oceanic deep-water-deposited particulates in the South China Sea (SCS). Six POPs, including polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs), polybrominated diphenyl ethers (PBDEs), polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs), polychlorinated diphenyl ethers (PCDEs), and polybrominated biphenyls (PBBs), were investigated in eight pooled samples from the SCS from 20 September 2013 to 23 March 2014 and 15 April 2014 to 24 October 2014 at depths of 2000 m and 3500 m. PBDEs were the most predominant compounds, with the highest mean Σ14PBDE of 125 ± 114 ng/g dry weight (d.w.), followed by Σ17PCDD/F, Σ12PBDD/F, and Σ12DL-PCB (275 ± 1930, 253 ± 216, and 116 ± 166 pg/g d.w., respectively). Most PBDD/F, PBB, and PCDE congeners were below the detection limits. PCDDs had the highest toxic equivalency (TEQ), followed by PBDDs and DL-PCBs. Among the six POPs, PBDEs were the major components of the marine-deposited particles, regarding both concentrations and mass fluxes. Compared to 3500 m, PBDE levels were higher at a depth of 2000 m. PBDE mass fluxes were 20.9 and 14.2 ng/m2/day or 68.2 and 75.9 ng/m2/year at deep-water 2000 and 3500 m, respectively. This study first investigated POP levels in oceanic deep-water-deposited particles from existing global data.

New insights into the effects of isomeric chlorine substitution on microstructures and enrichment capacities of functionalized polystyrene nanospheres

The substitution position of functional group is potential to affect the microstructure and adsorption performance of functionalized polystyrene (PS) nanospheres, yet to be explored. In this study, a series of hyper-crosslinked PS nanospheres with isomeric chlorine substitution have been prepared by emulsion polymerization and Friedel-Crafts reaction. The detailed characterizations indicated that the substitution position of chlorine greatly influenced the pore volume and specific surface area of constructed PS nanospheres, and the hyper-crosslinked ortho-Cl-functionalized nanospheres (o-xClFNs) possessed the highest specific surface area and largest pore volume, followed by para- and meta-Cl-functionalized nanospheres (p-xClFNs and m-xClFNs). Besides, these PS nanospheres were fabricated as even solid phase microextraction (SPME) coatings to study their extraction performance for substituted benzenes, chlorobenzenes, polychlorinated biphenyls (PCBs) and polybrominated biphenyls (PBBs). The experimental results showed that the p-xClFNs possessed the most outstanding extraction efficiencies for halogenated organic pollutants, and it was combined with gas chromatography-mass spectrometry (GC–MS) to develop a highly sensitive method, realizing the precise quantifications of trace PCBs and PBBs in environmental water. Our work provided invaluable insights on the choice of functional monomer to construct high-performance adsorbent, also demonstrated the important function of PS on the enrichments of organic pollutants.

Polybrominated biphenyls (PBBs) and prevalence of autoimmune disorders among members of the Michigan PBB registry

BackgroundPolybrominated biphenyls (PBBs), a class of endocrine disrupting chemicals, were the main chemicals present in one of the largest industrial accidents in the United States. We investigated the association between serum PBB-153 levels and autoimmune disorders among members of the Michigan PBB Registry. MethodsEight hundred and ninety-five members of the registry had both a serum PBB-153 measurement and had completed one or more questionnaires about autoimmune disorders. Autoimmune disorders were examined collectively and within specific organ systems. Sex-stratified unadjusted and adjusted log-binomial models were used to examine the association between tertiles of serum PBB-153 levels and autoimmune disorders. Models were adjusted by lifestage at exposure (in utero, childhood, adulthood), smoking history (never, past, current), and total serum lipid levels (continuous). We utilized cubic spline models to investigate non-linearity between serum PBB-153 levels and the prevalence of autoimmune disorders. ResultsApproximately 12.9% and 20.7% of male and female participants reported having one or more autoimmune disorders, respectively. After adjustment for potential confounders, we observed no association between PBB-153 tertiles and the composite classification of ‘any autoimmune disorder’ in either sex. We observed some evidence for an association between serum PBB-153 levels and rheumatoid arthritis in males and females; however, this was not statistically significant in females. We also observed some evidence for an association between serum PBB-153 levels and neurological- and thyroid-related autoimmune disorders in females, but again this was not statistically significant. Additionally, we identified dose-response curves for serum PBB-153 levels and the prevalence of autoimmune disorders that differed by lifestage of exposure and sex. ConclusionsWe observed some evidence that increasing serum PBB-153 levels were associated with three specified autoimmune disorders. Studies focusing on these three autoimmune disorders and the potential non-linear trend differences by lifestage of exposure warrant further investigation.

Polybrominated biphenyl exposure and thyroid function tests in electronic waste dismantling and general population of Chinese adults

This study aimed to determine the concentration of 35 PBB (polybrominated biphenyls) congeners in the human serum of residents from an electronic waste (e-waste) dismantling area compared to a control area in China. Additionally, four thyroid hormones, namely FT3, FT4, TSH, and TRH, were also analyzed. The findings revealed that the total PBB concentrations (sum of the 35 PBB congeners) ranged from 47.1 to 1360 ng/g lipid in the e-waste area and 105–1980 ng/g lipid in the control area. BB-1 and BB-10 were the dominant congeners in both study areas, followed by BB-209. Compared to the e-waste dismantling area, the control area samples had a significantly higher concentration of less-brominated (Br1–3) PBBs, including the concentrations of less-brominated congeners such as BB-1, BB-4, BB-9, and BB-10, which were significantly higher than those in the e-waste dismantling area. Conversely, more-brominated hexabromobiphenyl congeners BB- 153, BB-154 and BB-155 were found in samples from the e-waste dismantling area at significantly higher concentrations than in the control area. E-waste dismantling areas have released historically produced commercial PBB products, but equally not negligible is the exposure of the general population to newly produced PBB congeners. PBB concentrations in the e-waste dismantling area samples decreased with increasing age, while they increased with increasing age in the control area samples. Furthermore, stepwise multiple regression analysis showed a significant association between BB-103 concentrations and thyroid hormone levels. In addition, BB- 103 has the potential to interfere with the binding of T3 and thyroid hormone receptors (TR). Given these findings, the research on human exposure of PBB and the relationships between the PBB and thyroid hormones should be studied further.

Assessing Metabolic Differences Associated with Exposure to Polybrominated Biphenyl and Polychlorinated Biphenyls in the Michigan PBB Registry.

Polybrominated biphenyls (PBB) and polychlorinated biphenyls (PCB) are persistent organic pollutants with potential endocrine-disrupting effects linked to adverse health outcomes. In this study, we utilize high-resolution metabolomics (HRM) to identify internal exposure and biological responses underlying PCB and multigenerational PBB exposure for participants enrolled in the Michigan PBB Registry. HRM profiling was conducted on plasma samples collected from 2013 to 2014 from a subset of participants enrolled in the Michigan PBB Registry, including 369 directly exposed individuals (F0) who were alive when PBB mixtures were accidentally introduced into the food chain and 129 participants exposed to PBB in utero or through breastfeeding, if applicable (F1). Metabolome-wide association studies were performed for PBB-153 separately for each generation and (PCB-118, PCB-138, PCB-153, and PCB-180) in the two generations combined, as both had direct PCB exposure. Metabolite and metabolic pathway alterations were evaluated following a well-established untargeted HRM workflow. Mean levels were [standard deviation (SD): 13.9] for PBB-153 and (SD: 0.788) for . Sixty-two and 26 metabolic features were significantly associated with PBB-153 in F0 and F1 [false discovery rate (FDR) ], respectively. There were 2,861 features associated with (FDR ). Metabolic pathway enrichment analysis using a bioinformatics tool revealed perturbations associated with in numerous oxidative stress and inflammation pathways (e.g., carnitine shuttle, glycosphingolipid, and vitamin B9 metabolism). Metabolic perturbations associated with PBB-153 in F0 were related to oxidative stress (e.g., pentose phosphate and vitamin C metabolism) and in F1 were related to energy production (e.g., pyrimidine, amino sugars, and lysine metabolism). Using authentic chemical standards, we confirmed the chemical identity of 29 metabolites associated with levels (level 1 evidence). Our results demonstrate that serum PBB-153 is associated with alterations in inflammation and oxidative stress-related pathways, which differed when stratified by generation. We also found that was associated with the downregulation of important neurotransmitters, serotonin, and 4-aminobutanoate. These findings provide novel insights for future investigations of molecular mechanisms underlying PBB and PCB exposure on health. https://doi.org/10.1289/EHP12657.

Computational study of mechanistic pathway and effect of zero valent metals on reductive debromination of some polybrominated biphenyls

Complete debromination of three polybrominated biphenyls (PBBs), namely 2,2′,3,3′,4,4′-hexabromobiphenyl (PBB-128), 2,2′,3,3′,4,5- hexabromobiphenyl (PBB-129) and 2,2′,3,3′,4,5′- hexabromobiphenyl (PBB-130) aided by zero valent magnesium (Mg0) andzinc (Zn0) in the presence of methanol was studied computationally using dispersion corrected ωB97XD functional with cc-pVTZ basis set. All possible debromination pathways were explored for each parent PBB and the most energetically favoured pathway was identified. Mono-debromination of each PBB afforded a two-step mechanism, viz, formation of a highly charged covalent intermediate that involves a phenyl-metal-bromine connectivity and protonation by methanol molecule.Total activation energy for the step-wise removal of one bromine substituent increased along the debromination pathway. Using substituent positions, favourable sequence of stepwise debromination was found to follow the order 3 or 3′2 or 2′ 4 or 4′, while Mg0catalyzed the debromination reaction better than Zn0. The order of ease of debromination was found to be PBB-128PBB-130PBB-129.

Etched hollow periodic mesoporous organosilica with enlarged pore size for high-performance solid phase microextraction of polybrominated biphenyls

Hollow mesoporous silica has attracted increasing attention due to its outstanding characteristics such as low density, large void, mesoporous channel, and large specific surface area. Herein, a kind of etched hollow periodic mesoporous organosilica (EHPMOS) with enlarged mesopore size was successfully synthesized for high-performance solid phase microextraction (SPME). The etched silica material was prepared as a SPME fiber with uniform morphology, and the enrichment capacities for polybrominated biphenyls (PBBs) were systematically studied. In particular, the EHPMOS showed significant enrichment factors (158–9516) for PBBs. In addition, based on the home-made SPME fiber and gas chromatography-mass spectrometry (GC–MS), an ultra-sensitive analytical method was developed, with low limits of detection (0.11–0.32 ng·L-1), a wide linear range (1–1000 ng·L-1), and satisfactory reproducibility. And accurate quantifications of ultra-trace PBBs in environmental water sample were achieved.

Worldwide Efficiency of Bioremediation Techniques for Organic Pollutants in Soil: A Brief Review

Soil pollution is a major human and environmental issue. Among the several components of soil degradation, organic contaminant in soil is regarded as a significant factor that causes considerable damage to the environment along with several health dangers to humans. Polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polychlorinated dibenzofurans, poly-brominated biphenyls, organic fuels particularly gasoline and diesel, herbicides, insecticides (carbamate and organophosphorus) are by far the most common forms of organic pollutants identified in soils. The employment of living organisms such as microorganisms and plants in bioremediation technology reduces/degrades, eliminates, and transforms pollutants found in soils, sediments, and water. This review examine and critically view the efficiency of bioremediation techniques for the polluted sites. The most common bioremediation technologies for the treatment of organic pollutants are bioventing, bio-sparging, bio-slurping, bio-augmentation, phytoremediation, bio-immobilization, bio-sorption, composting, land farming, aerobic degradation, co-metabolic and natural attenuation. The efficiency of these techniques depends on the pH, type of soil, level of oxygen, any other electron acceptors, temperature, and the nutrients. Selection of the treatment process depends upon the type of pollutant, concentration of the contaminant, site and source of pollution. All the treatment techniques are not good for all type of pollutants. Cost-effective techniques are mostly used worldwide as they have more public acceptance. Pump and treat methods were mostly used in Past but due to its non-reliability and excessive cost, these techniques are no longer in use.
 Keywords: Bioremediation Techniques; Soil Pollution; Organic Pollutants; Efficiency, Environmental Contamination
 
 Copyright (c) 2023 Geosfera Indonesia and Department of Geography Education, University of Jember
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Persistent organic pollutants in air from Asia, Africa, Latin America, and the Pacific

In support of the United Nations Environment Programme (UNEP) global monitoring plan under the Stockholm Convention concentrations of persistent organic pollutants (POPs) were determined during two years in air from 42 countries in Asia, Africa, Latin America, and the Pacific by using polyurethane foams installed in passive samplers. The compounds included were polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenylethers (PBDEs), one polybrominated biphenyl and hexabromocyclododecane (HBCD) diastereomers. Total-DDT and PCBs were the highest in concentrations in about 50% of the samples, which shows their high persistency. Total DDT in air from the Solomon Islands ranged from 200 to 600 ng/polyurethane foam disk (PUF). However, at most locations, a decreasing trend is observed for PCBs, DDT and most other OCPs. Patterns varied per country with e.g. elevated dieldrin in air from Barbados and chlordane in air from the Philippines. A number of OCPs, such as heptachlor and its epoxides, some other chlordanes, mirex and toxaphene have decreased down to almost undetectable levels. PBB153 was hardly found and penta and octa--mix related PBDEs were also relatively low at most locations. HBCD and the decabromodiphenylether were more prominent at many locations and may even still increase. To draw more holistic conclusions more colder climate countries should be included in this program.

Using an optimized relative response factor database to simplify a pyrolyzer/thermal desorption-gas chromatography-mass spectrometry method of screening for phthalate esters, polybrominated diphenyl ethers, and polybrominated biphenyls in polymers

The international analytical standard IEC 62321–3–3 describes a method for the screening analysis of phthalate esters, polybrominated diphenyl ethers (PBDEs), and polybrominated biphenyls (PBBs) in polymers by pyrolyzer/thermal desorption-gas chromatography-mass spectrometry (Py/TD-GC/MS). The IEC 62321–3–3 method uses a database of relative response factors (RRFs) (calculated by dividing the response factor (RF) for a target compound by the RF value for a substitute compound (SC) selected from among all target compounds) to quantitate each targeted analyte. A drawback of this method is that a separate RRF database must be created from expensive standard solutions that contain each targeted compound for each instrument, which is a labor-intensive task. In this study, we have developed a “ready-to-use” RRF database that can be used on multiple different instruments. This method eliminates the need to create an RRF database for each instrument and greatly simplifies the screening workflow described in the IEC 62321–3–3 standard. Because it only requires a mixed n-alkane solution and polymer reference materials, which are generally easy to procure and easy to use, the method is highly convenient and suitable for general-purpose use. Assigning tetra-BDE, penta-BDE, deca-BDE, or deca-BB as the SC for each PBDE and PBB analyte allowed the variance in RRFs between instruments to be reduced to a degree suitable for screening analysis. When this method was applied, recovery rates of individual PBDEs and PBBs remained within the range of 74–130 % over an extended period of 54 months. Simultaneous analysis of phthalate esters, PBDEs, and PBBs in various polymer reference materials was also performed with the optimized method on four different instruments and recovery rates of each targeted compound were evaluated. The recovery rates for each phthalate ester, total PBDEs, and total PBBs were within the range of around 100 ± 30 % for all tested samples.

Dietary exposure to thyroid disrupting chemicals: a community-based study in Canada

The marine ecosystem around the Island of Newfoundland is contaminated by thyroid disrupting chemicals (TDCs). Coastal inhabitants may be exposed to TDCs through consumption of contaminated local seafood products and affecting thyroid functions. The aim of this study was to explore: (1) consumption frequency of local seafood products consumed by rural residents, (2) thyroid hormones (THs) and TDCs concentrations in residents, (3) relationships between local seafood consumption, TDC concentrations, and THs. Participants (n = 80) were recruited from two rural Newfoundland communities. Seafood consumption was measured through a validated seafood consumption questionnaire. Blood samples were collected from all participants and tested for THs (thyroid stimulating hormone, free thyroxine, free triiodothyronine) and TDCs, including polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs), and dichlorodiphenyldichloroethylene (p,p′-DDE). Cod was the most frequently consumed local species, but there was a wide range of other local species consumed. Older participants (>50 years) had greater plasma concentrations of PBB-153, PCBs and p,p′-DDE, and males had higher concentrations of all TDCs than females. The consumption frequency of local cod was found to be positively associated with several PCB congeners, p,p′-DDE and ∑14TDCs. There was no significant relationship between TDCs and THs in either simple or multivariate linear regression analyses.

Elimination of PBB-153; findings from a cohort of Michigan adults

BackgroundAn industrial accident led to the widespread contamination of polybrominated biphenyl (PBB), a flame retardant, into the food system in Michigan in the 1970's. PBB continues to be detected in Michiganders' blood some forty years later. It is necessary to understand the elimination rate and half-life of PBB because it may provide clues on how to hasten the elimination of it from the human body. MethodsSerum samples were taken from young adult and adult participants of the Michigan PBB registry from 1974 to 2019. A single compartment model was assumed for the elimination rate for PBB-153 in young adults and adults (≥16 years). Generalized linear mixed models were used to estimate the average elimination rate of PBB-153 and allowed for a random intercept and slope for the time between measurements. Models were adjusted for age at exposure, body mass index (BMI) at initial measurement, and smoking. Models were also stratified by demographic characteristics. ResultsIn total, 1974 participants contributed 4768 samples over a forty-year span. The median initial PBB-153 level was 1.542 parts per billion (ppb) (Range: 0.001–1442.48 ppb). The adjusted median participant-specific half-life for PBB-153 was 12.23 years. The half-life of PBB-153 was lengthened by higher initial PBB level (∼1.5 years), younger age at exposure (∼5.4 years), higher BMI (∼1.0 years), and increased gravidity (∼7.3 years). Additionally, the half-life of PBB-153 was shortened by smoking status (∼-2.8 years) and breastfeeding (∼-3.5 years). ConclusionsConsistent with previous studies, PBB-153 has been demonstrated to have a long half-life in the human body and may be modified by some demographic characteristics. These updated estimates of half-life will further support evaluation of health effects associated with PBB exposure. Investigations into mechanisms to accelerate elimination and reduce body burdens of PBB-153, especially those related to body weight, are needed.