Intake Of Polybrominated Diphenyl Ethers Research Articles

Safety evaluation of organochlorine pesticides and polybrominated diphenyl ethers in imported canned fish in Nigeria

Organochlorine pesticide (OCP) and polybrominated diphenyl ether (PBDE) concentrations were measured in thirty popular brands of imported canned fish (mackerel, sardines, and tuna) in Nigeria to ascertain potential threats to humans arising from their consumption. The Σ20 OCP concentrations in mackerel ranged from 0.47 to 7.36 ng g−1, while those of tuna and sardines varied from 1.06 to 2.19 and 0.11 to 12.7 ng g−1, respectively. The Σ39 PBDE concentrations in mackerel varied from 0.06 to 4.21 ng g−1, while those of tuna and sardines ranged from 0.19 to 3.18 and 0.04 to 8.26 ng g−1, respectively. The estimated daily intake (EDI) of OCPs and PBDEs from ingestion of the canned fish by adults and children were in the magnitude of 0.03 to 17.6 ng kg−1 bw day−1 and 9.9 × 10−3 to 11.5 ng kg−1 bw day−1 respectively. The hazard index (HI) and total cancer risk (TCR) values for OCPs and PBDEs from ingestion of the canned fish were less than 1 and 10−6, respectively. The dietary intakes of OCPs and PBDEs from these brands of canned fish by adults and children result in no adverse non-cancer and cancer risks.

Characterization and distribution of polybrominated diphenyl ethers in shellfish in Shenzhen coastal waters and assessment of human health risks

This study aims to investigate the profiles of polybrominated diphenyl ethers (PBDEs) in shellfish obtained from Shenzhen coastal waters and assess the potential health risks. We analyzed 74 shellfish samples from eight different species for PBDEs (BDE-28, −47, −99, −100, −153, −154, −183, −209). The concentrations of total PBDEs in different shellfish species ranged from 2.02 to 360.17 pg g−1 wet weight, with the highest levels found in Pectinidae, Babylonia areolate, Ostreidae, Perna viridis, Haliotis diversicolor, Corbiculidae, Pinctada margaritifera, and Veneridae in descending order. Among the PBDE congeners analyzed, BDE-47 was the most abundant, followed by BDE-154 and BDE-153. Furthermore, the estimated daily intake of PBDEs through shellfish consumption for Shenzhen residents were between 0.11 and 0.19 ng kg−1(bw) day−1. To our knowledge, this is the first study to systematically investigate the profiles of PBDEs in eight different shellfish species from Shenzhen's coastal waters and evaluate the potential human health risks associated with shellfish consumption.

Dietary exposure and risk assessment of polybrominated diphenyl ethers in the Republic of Korea: A nationwide study

In this study, the dietary exposure to seven polybrominated diphenyl ethers (PBDEs) congener groups, including 22 types of PBDEs compounds, through consumption of 80 food items in Korean diets along with their risk assessment has been investigated. To process this, the concentrations of the target PBDEs in samples of food items were measured. The consumption amounts of the target food items were derived from the results of the 24 h food recall interview of subjects who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) from 2015 to 2019. Thereafter, the estimated daily intake and risk of exposure for each PBDEs congener group were assessed. Results indicate that although exposure to the target PBDEs was not significant enough to cause a potential health risk, deca-BDE (BDE-209) was the dominant congener in terms of both exposure and risk for consumers in all age groups. Furthermore, while eating seafood was the dominant path for dietary exposure to PBDEs, exposure to octa-BDEs was mostly through livestock products. Accordingly, to protect all consumers, especially those aged below 2 years and over 65 years, more accurate food quality management is required for controlling the dietary intake of PBDEs.

Simultaneous determination of hexabromocyclododecanes, polybrominated diphenyl ethers, and dechlorane-related compounds in boxed sushi meals using a developed analytical method

We investigated the concentrations of halogenated flame retardants (HFRs), which include hexabromocyclododecanes (HBCDDs), polybrominated diphenyl ethers (PBDEs), and dechloranes and related compounds (DRCs), in 25 typical ready-made boxed sushi meals (each divided into seafood and non-seafood portions) using a developed simultaneous analytical method involving accelerated solvent extraction and gel permeation chromatographic separation. The developed method yielded good recoveries of surrogates (72–122 %). HBCDDs, PBDEs, and DRCs were detected in all seafood portions. While DRCs were also frequently detected in non-seafood portions, HBCDDs and PBDEs were hardly detected. The estimated dietary intakes of HBCDDs, PBDEs, and DRCs from boxed sushi meals were well below the corresponding health-based guideline values. In conclusion, our study suggests that the intake of HFRs from boxed sushi meals poses low concern for consumer health and that the developed simultaneous analytical method is highly useful for determining HFRs in seafood-based meals.

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.

Positive association between dietary exposure to polybrominated diphenyl ethers and breast cancer risk in the French E3N cohort: The role of vegetable oil consumption.

Exposure to endocrine-disrupting chemicals, like Polybrominated diphenyl ethers (PBDEs), is suspected of playing a role in the occurrence of breast cancer. Moreover, there is growing evidence that food chemical contaminants, especially lipophilic ones such as PBDEs, could interact with different components of the diet. The objective of the present study was to assess the association between dietary intake of PBDEs and breast cancer risk in the French E3N cohort study, and to investigate the potential modification of this association by vegetable oil consumption. The study included 67879 women. Intakes of eight PBDEs were estimated using food consumption data from a validated semi-quantitative food frequency questionnaire, and food contamination levels measured by the French Agency for Food, Environmental and Occupational Health and Safety (ANSES). Cox proportional hazards models were used to estimate Hazard Ratios (HR) and 95% Confidence Intervals (CI) for the association between total PBDEs dietary intake and breast cancer risk. Interaction measures for vegetable oil consumption were estimated on both additive and multiplicative scales. The women were followed for a maximum of 21.4years, and 5 686 developed an incident breast cancer. A positive linear trend was highlighted between dietary intake of PBDEs in quintile groups and breast cancer risk, borderline with statistical significance (p-trend=0.06, HRQ5vsQ1 and 95% CI: 1.09 [0.99;1.20]). Interaction measures for vegetable oil consumption were significant in both additive and multiplicative scales. Higher effect sizes of the association were highlighted in high consumers of vegetable oil, i.e. ≥4.6g/day (HRQ5vsQ1 and 95% CI: 1.23 [1.08; 1.40]), and almost no effect were found in low consumers (HRQ5vsQ1 and 95% CI: 0.97 [0.86; 1.10]). Highlighting such interactions between nutrients and chemicals is crucial to develop efficient dietary recommendations to limit the negative health effects associated with exposure to food chemical contaminants.

A nationwide survey of 20 legacy brominated flame retardants in indoor dust from China: continuing occurrence, national distribution, and implication for human exposure.

Despite the restrictions on polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDDs), these chemicals are still ubiquitous environmental pollutants. In this study, we measured the concentrations and profiles of 17 PBDE congeners and 3 HBCDD isomers in indoor dust samples collected from 23 provinces and cities across China. The summed concentrations of PBDEs (Σ17PBDEs) ranged from 4.19 to 817ng/g, with an average of 171 ± 184ng/g. BDE-209 was the most abundant congener. The concentrations of HBCDDs ranged from 6.65 to 1335ng/g, with an average of 236 ± 324ng/g. Unlike commercial HBCDD formulations, α-HBCDD was the predominant isomer in the indoor dust samples analyzed. Geographical distributions showed that the concentrations of PBDEs and HBCDDs varied significantly among different regions. Higher PBDE and HBCDD levels were observed in samples from eastern coastal and economically developed regions. Further, we estimated the daily intakes of PBDEs and HBCDDs through the routes of dust ingestion and dust dermal absorption for different age groups. Dust dermal absorption is an unneglectable exposure pathway to PBDEs and HBCDs for the Chinese population. Among the age groups, infants had the highest exposure via dust dermal absorption, and toddlers had the highest exposure via dust ingestion. Compared with the threshold values, the exposure doses of PBDEs and HBCDDs are unlikely to pose significant health concerns for both infants and adults in China. This is the first national survey of PBDEs and HBCDDs in indoor dust samples across China after the restriction.

Exposure to Polybrominated Diphenyl Ethers in the Sixth Total Diet Study — China, 2016–2019

What is already known about this topic?Polybrominated diphenyl ethers (PBDEs) were widely used in many industrial and commercial materials as flame retardants, and its related exposure threatens human health.What is added by this report?The Sixth Total Diet Study (TDS) indicated that the dietary intake of PBDEs was unlikely to pose significant health risks for the general Chinese people using the margin of exposure (MOE) approach recommended by the European Food Safety Authority (EFSA).What are the implications for public health practice?This study highlights the necessity of continuous national monitoring of the dietary intake and strict legislation of PBDEs in China.

Risk assessment of PBDEs and PCBs in dust from an e-waste recycling area of China

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) are widely used in outdated electronic and electrical products. In the present study, dust samples from houses, kindergartens, and roads were collected in Guiyu, where informal e-waste recycling activities have been sustained since the 1980s. Haojiang was chosen as a reference site without e-waste pollution. A total of 20 PBDE congeners and 18 PCB congeners was measured. Concentrations of total PBDEs and PCBs in dust samples from Guiyu were significantly higher than those from Haojiang. In Guiyu, kindergarten dust had the highest concentration of PCBs in these three typical environments, whereas the concentration of PBDEs showed no significant difference. Concentrations of PBDEs in Haojiang house dust were found significantly higher than other two environmental dusts. According to the questionnaires, we found that factors such as shoe cabinets, electrical products, and potted plants might affect PBDE and PCB concentrations in house dust. Daily intake of PBDEs and PCBs via dust ingestion was estimated after correction by their house, kindergarten, and road dust concentrations. The mean estimated daily intake (EDI) of PBDEs for Guiyu children was far lower than the oral reference dose recommended by the environmental protection agency (EPA). The Guiyu children seem to have a higher trend of daily intakes of PCBs although their EDIs not being calculated accurately due to the low detection rate. Child exposure to PBDEs via dust ingestion in Guiyu was 36 times higher than those in Haojiang. This indicates that children from e-waste-polluted areas stay in surroundings with heavy burdens of PBDEs, even PCBs. The risk to their health from contaminants is a severe concern.

Decreases in Concentrations and Human Dietary Intakes of Polychlorinated Biphenyls (PCBs) and Polybrominated Diphenyl Ethers (PBDEs) in Korean Seafood Between 2005 and 2017.

Concentrations of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were measured in 23 seafood species widely consumed by the Korean population in the periods of 2005-2007, 2010-2011, and 2015-2017. The Σ82PCB (sum of 82 PCB congeners) and Σ19PBDE (sum of 19 PBDE congeners) concentrations in the seafood samples of 2015-2017 were 0.06-6.69ng/g wet weight and 0.01-1.60ng/g wet weight, respectively. The Σ82PCB and Σ19PBDE concentrations in the samples were significantly correlated. Elevated PCB and PBDE concentrations were found in fatty fish, such as herring, mackerel, and tuna. The current human intakes of PCBs and PBDEs were much lower than the tolerable daily intake or lowest observed adverse effect level. The levels and human dietary intakes of PCBs and PBDEs in the 2015-2017 survey showed decreases of 17-73% and 57-86%, respectively, compared with those in 2005-2007 and 2010-2011 surveys. This indicates that global bans on PCBs and PBDEs have been effective, and their levels and human exposure to them have been gradually declining.

Different risk assessment methodologies applied for infant’s exposure for polybrominated diphenyl ethers: Implications for public health

The study aimed to determine the levels of selected polybrominated diphenyl ethers (PBDEs) in human milk and characterize the risk for breastfed infants using EFSA and U.S. EPA methodologies. The predominant PBDEs for which EFSA and U.S. EPA established toxicological reference values have been selected for evaluation. Concentrations of BDE-47, BDE-99 and BDE-153 were determined in breast milk samples from 25 mothers living in Poland. The estimated daily intakes of PBDEs for breastfed infants were calculated based on the results of PBDE concentrations obtained for each case and for the mean concentrations of the analyzed compounds. The estimated infants' daily intake of PBDEs from human milk was below U.S. EPA RfD, therefore not considered a health risk. In calculations according to approach applying MOEs (EFSA), we indicated a potential health concern with respect to exposure of infants to BDE-99. The calculated results based on the available methodologies do not provide clear information for the purposes of consumer safety assessment regarding exposure to the BDE-99 congener. Present study indicates the necessity to develop an internationally harmonized strategy for assessing the risk posed by polybrominated diphenyl ethers, especially for breast-fed infants.

Estimation of exposure to polybrominated diphenyl ethers of people surrounding Nanjing Chemical Industry Park via fish consumption

Nanjing Chemical Industry Park (NCIP) is an important industrial base with more than 300 chemical plants. Taking NCIP as a research area, this article conducted a random sampling survey on the aquatic product consumption of residents in the NCIP and its surrounding areas. Then this study preliminarily estimated the exposure level of local residents to polybrominated diphenyl ethers (PBDEs) associated with fish consumption. The mean intake of Σ6 PBDEs via fish consumption was 0.69 ng/kg body weight b.w./day with a range of 0.35-1.63 ng/kg b.w./day. There was no significant difference in total intake of PBDEs at different body weights. Among the six PBDEs congeners, BDE-47 was dominant in the total intake, with an average contribution rate of 77%. The daily exposure to PBDEs decreased with the increase of body weight. During this period, the total intake of PBDES through fish consumption was at a low level. Overall, the estimated daily intake of total PBDEs was far below the LOAEL for the population in this region.

Levels of polybrominated diphenyl ethers (PBDEs) in indoor dusts in Lagos and Ibadan, Nigeria

Polybrominated diphenyl ethers (PBDEs) were analysed in dust samples collected from 10 homes, 10 cars, 10 offices and 10 schools in 2 different cities, Lagos and Ibadan, Nigeria. The daily dust ingestion was calculated for all the indoor microenvironment studied. Extraction of PBDEs was by ultrasonication and was analysed on a gas chromatography microelectron capture detector. This represents the first PBDE study in school dust on the African continent and also first PBDE study in Ibadan. Lagos is Africa’s most populated city and Ibadan is the third largest city in West Africa and of historical significance. The concentrations of ΣPBDEs (BDE 28, 47, 99,100,153,154,183 and 209) in homes, cars, offices and schools was 2.24–11500 ng/g; 1.20–258 ng/g; 3.76–687 ng/g and 0–471 ng/g, respectively. Generally, dust samples from Lagos had higher median concentration as compared to Ibadan. BDE-47, BDE-99 and BDE-183 were the most prominent congeners recorded. Interestingly, BDE-209 which is prevalent in dust samples in temperate region had a low concentration in this study (especially in car dust). This may be attributed to the photodegradation of BDE-209 due to Nigeria being a tropical country. samples in Lagos, very high median concentration levels of PBDE was present in-house dusts, with slightly lower PBDE levels recorded in office dust. BDE-100 and BDE-183 were the most prevalent congeners in school dust samples. The median concentration obtained was lower when compared to Australian schools. The concentrations of PBDE in house and office dusts in Nigeria was less than studies in the UK and US but similar to values from South Africa and Egypt. The daily intake of PBDEs from all indoor dust samples were below USEPA reference dose (RfD) for oral exposure for all BDE congeners. For all indoor dust categories, toddlers had the possibility for the highest ingestion rate, and this is of serious concern. Lastly, the method scaled analytical Eco-Scale evaluation and Green Analytical Chemical Procedure Index as “an acceptable green analysis method”.

Human exposure to legacy and emerging flame retardants in indoor dust: A multiple-exposure assessment of PBDEs

Human exposure to flame retardants (FRs) in indoor environments is a growing concern. In this study, the concentrations of polybrominated diphenyl ethers (PBDEs) and their alternatives, such as novel brominated flame retardants (NBFRs), dechlorane plus (DP), and organophosphate flame retardants (OPFRs), were measured in dust from indoor environments in Korea to investigate their occurrence, contamination profiles, and health risks. Legacy and emerging FRs were detected in dust samples, indicating widespread contamination of indoor environments. The concentrations of alternative FRs were higher in dust from offices compared with house dust, suggesting that office environments are major consumers of alternative FRs. Similar compositional profiles for indoor dust were found for PBDEs in different microenvironments and regions, while OPFR composition varied widely due to disparate applications. The estimated daily intakes of PBDEs, NBFRs, and OPFRs via dust ingestion were lower than the reference doses proposed by previous studies. A multiple-exposure assessment showed that dust ingestion was a major contributor to total PBDEs for toddlers and adults. However, major exposure pathways of BDEs 47 and 209 differed between toddlers and adults. Our study suggests that multiple exposure pathways should be considered in a comprehensive exposure assessment of PBDEs.

A comprehensive risk assessment of human inhalation exposure to atmospheric halogenated flame retardants and organophosphate esters in an urban zone

Inhalation exposure to flame retardants used as additives to minimize fire risk and plasticizers is ubiquitous in human daily activities, but has not been adequately assessed. To address this research gap, the present study conducted an assessment of human health risk for four age groups through inhalation exposure to size fractionated particle-bound and gaseous halogenated flame retardants (polybrominated diphenyl ethers (PBDEs) and alternative halogenated flame retardants (AHFRs)) and organophosphate esters (OPEs) at indoor and outdoor environments (school, office, and residence) in three districts of a megacity (Guangzhou, China). Results demonstrated that OPEs were the dominant components among all targets. Indoor daily intakes of PBDEs and OPEs were 13–16 times greater than outdoor levels for all age groups. Gaseous OPEs contributed significantly greater than particle-bound compounds to daily intakes of all target compounds. Based on the different life scenarios, hazard quotient (HQ) and incremental life cancer risk (ILCR) from adults exposure to PBDEs and OPEs in indoor and outdoor settings were the greatest, followed by adolescents, children, and seniors. The estimated HQ and ILCR for all age groups both indoors and outdoors were lower than the safe level (HQ = 1 and ILCR = 10−6), indicating that the potential health risk for local residents in Guangzhou via inhalation exposure to atmospheric halogenated flame retardants and OPEs was low.

Exposure to PBDEs associated with farm animal meat consumption

One of the ways to reduce the number of fires and the amount of damage caused by them is to use flame retardants (FRs). Polybrominated diphenyl ethers (PBDEs), like other FRs, have been used in a wide array of easily flammable products. As they are not chemically bonded with materials, PBDEs can be released from polymers into the environment. PBDEs can act as endocrine disruptors and affect neurological and thyroid activity. Although human intake of PBDEs is mainly through food, data about meat as a PBDE source and human exposure through diet are limited. The objective of the present study was to develop a comprehensive database of congener-specific PBDE concentrations in farm animal muscle and to characterize potential consumer exposure. For exposure assessment, two consumption scenarios were used for adults and children. The dietary exposure to PBDE congeners is based on the assumed portion size of 100 g of different meat species. Calculations for the participants were performed using food consumption data of the Statistical Yearbook (2015/2016). The intake of PBDEs was estimated as the median (P50) and the average for all kinds of tested meat. For health risk assessment, the margin of exposure (MOE) approach was used. MOE values were in range from 5 to 149 352 132. The obtained results indicate that concentrations of ten tested congeners (BDE-28,47,49,99,100,138,153,154,183,209) in different kinds of farm animal meat (cow, chicken, farm deer, horse, ostrich, pig, rabbit, sheep, turkey) are low and meat consumption does not pose a risk for human health.

Infants' Neurodevelopmental Effects of PM2.5 and Persistent Organohalogen Pollutants Exposure in Southern Taiwan

ABSTRACT Several studies have stated the harmful effects of PM2.5 to population health, including disruption of neurological development. However, the mechanism behind the neurodevelopmental effects of ambient PM2.5 and postnatal PBDEs and OCPs exposure is still unknown. Our goal was to determine influence of breastmilk residues, polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs), to the infants’ neurodevelopment with respect to high and low PM2.5 exposure areas. The participants were recruited from high PM2.5 exposure areas (n = 32) and low PM2.5 exposure areas (n = 23) of southern Taiwan. The extracted 14 PBDEs and 20 OCPs compounds were analyzed using gas chromatography coupled with mass spectrometer. The infants, aging from 8-12 months, were examined by Bayley Scales of Infants and Toddlers Development, Third Edition (Bayley-III) for neurodevelopment. Results showed that high PM2.5 exposure caused reduced head circumference and had significant effects on the motor skill and social emotional development. For breastmilk PBDEs, a positive correlation between BDE-196 and social emotion, after multivariate analysis with adjustment of confounders, was observed while BDE-99, 196, 197, and 207 showed higher magnitudes in low PM2.5 areas than in high PM2.5 areas. For OCPs, only γ- hexachlorcyclohexanes (γ-HCH) presented the significant difference between high and low PM2.5 exposure areas. Most breastmilk OCPs residues, including 4,4’-dichlorodiphenyltrichloroethane (4,4’-DDT), γ-HCH, endrin, and heptachlor epoxide showed negative impact on the Bayley-III scores after multivariate analysis. In conclusion, infants’ neurodevelopment was significantly correlated with the location of PM2.5 exposure and breastmilk intake of certain PBDEs and OCPs. Breastmilk OCPs might obviously affect infants’ neurodevelopment more compared to breastmilk PBDEs based on our finding. Moreover, this study further employs awareness about viable effects of PM2.5 in infants’ neurodevelopment.

Polybrominated diphenyl ethers (PBDEs) in dust in typical indoor public places in Hangzhou: Levels and an assessment of human exposure

Polybrominated diphenyl ethers (PBDEs) are organic pollutants (POPs) with the characteristics of environmental persistence, long-distance transmission in nature, biological accumulation and toxic effects on human health. To investigate the level of contamination due to PBDEs in typical indoor public places in Hangzhou, dust samples were collected from ten supermarkets, three electronic markets and five different areas throughout one commodity market. Based on sample pretreatment and GC-ECD instrumental analysis, the contamination characteristics, sources and the influencing factors of 14 PBDE congeners were analyzed. The results revealed that the mean of ∑14PBDEs in dust in the supermarkets and electronic markets was 546.13 ng/g and 1140.05 ng/g, respectively, while in the commodity market the mean was 1005.42 ng/g and varied in the five different areas as follows: shoe areas (1367.22 ng/g) > parking lot (1001.05 ng/g) > waiting halls (970.31 ng/g) > packet areas (933.23 ng/g) > curtain areas (755.28 ng/g). The high levels of PBDE were attributed to the quantity of electrical appliances in the supermarkets (r = 0.708*, p < 0.05) and the electronic markets (r = 0.799**, p < 0.05) through Spearman correlation coefficient analysis. BDE-209 was the dominant congener, accounting for 53.72% in supermarkets and 64.25% in electronic markets. The calculated inhalation exposure revealed that the exposure level of PBDEs varied in supermarkets, electronic markets and commodity markets, with values of 0.476 ng/day/kg, 0.993 ng/day/kg and 0.876 ng/day/kg, respectively. Moreover, BDE-209's contribution to the total intake of PBDEs was the highest, with a value of 0.072–0.970 ng/day/kg, while the value of BDE-183 was the lowest, with a value of 0–0.020 ng/day/kg. The exposure level of PBDEs in the studied indoor public places was lower than the reference dose of EPA.

Bioaccessibility of BDE 47 in a simulated gastrointestinal system and its metabolic transformation mechanisms in Caco-2 cells

Polybrominated diphenyl ethers (PBDEs) have been regarded as ubiquitous environmental pollutants. However, the absorption and transformation of these compounds after ingestion are not well understood yet. In this study, the bioaccessibility and metabolic pathway of 2,2′,4,4′- tetrabromodiphenyl ether (BDE47) was investigated in an in vitro digestion/Caco-2 cell. Gastric and intestinal bioaccessibilities of BDE47 in 5 kinds of spiked soil samples were ranging from 11.39 ± 0.83% to 36.02 ± 4.34%, and 48.24 ± 3.24% to 81.52 ± 6.43%, respectively. Upon exposure to differentiated Caco-2 cells for 6 h, it was found that only a small amount of BDE47 in the gastrointestinal (GI) solution could pass through Caco-2 cells, and might enter the body. Moreover, BDE47 was found to be metabolized or transformed into BDE28, BDE75, BDE37, BDE32, BDE15 and BDE8 in Caco-2 cells. The metabolic pathway could be explained by using the Becke three-parameter hybrid functional (B3Lucifer yellow CHP) in the Density Functional Theory (DFT), denoted as the values of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) at the atoms of BDE47 and its metabolic products. The obtained results suggest that oral intake of PBDEs is associated with low bioaccessibility, but also emphasize the risks associated with oral ingestion, namely toxicity resulting from the debromination of highly brominated diphenyl ethers. Although highly brominated diphenyl ethers are known to be the least toxic PBDEs, the debrominated products in human intestinal epithelia may elicit greater than expected toxicity.

The occurrence of brominated flame retardants in the atmosphere of Gauteng Province, South Africa using polyurethane foam passive air samplers and assessment of human exposure

Polyurethane foam passive samplers were deployed between May 2016 and January 2017 to evaluate concentrations of polybrominated diphenyl ethers (PBDEs), selected alternative flame retardants (AFRs) and total hexabromocyclododecane (HBCDD) (sum of α-, β-, and γ-HBCDD). The PUF air samplers were deployed in semi–urban, urban, industrial and landfill sites in Gauteng Province, South Africa. The acquired results presented a clear semi urban–industrial–urban–landfill concentration gradient for all BFRs measured. Taking into account 2 sampling periods (cold and warm periods) (n = 16), the atmospheric concentrations of ∑9PBDEs, HBCDDs and ∑AFRs were 100–2820 pg m−3, 12–117 pg m−3 and 41–4660 pg m−3, respectively, for the sparsely populated residential area, densely populated residential area, industrial area and the landfill area. In all cases, BDE 47, 99, and 209 were the most dominant congeners with high detection frequencies. The highest calculated daily exposure dose in Gauteng Province atmosphere was 0.61 and 1.54 ng kg −1 – bw d −1 for adults and children respectively. The estimated total intake of PBDEs was 0.47–33.4 ng kg −1 – bw d −1, which was generally below the lowest adverse effect limit (LOAEL), suggesting that the residents of Gauteng Province may not be significantly affected as a result of their exposure to these pollutants through inhalation. However, this does not necessarily suggest that the pollutants are harmless to human health, since they have the tendency to bioaccumulate in biological systems. Incidentally, this is the first study from Africa to report on the atmospheric concentrations of PBDEs, HBCDDs and AFRs in urban, landfill and industrial areas. The findings from this study further highlight the contributory role of landfills as potential sources of BFRs into the atmosphere.