Abstract  Polybrominated diphenyl ethers (PBDEs) have been widely studied in sediments from the North American Great Lakes; however, no studies have been conducted of occurrences of methoxylated (MeO-) PBDEs in abiotic compartments in this region. In the present study, 23 tri- to hepta-PBDEs and 12 MeO-PBDEs were analyzed in dated sediment cores collected from two inland lakes (White Lake and Muskegon Lake) in Michigan, USA. Concentrations of Sigma(23)PB DEs ranged from 3.9 x 10(-1) to 2.4 x 10 and from 9.8 x 10(-1) to 3.9 x 10(0) ng/g dry weight in White Lake and Muskegon Lake, respectively. The historical trends of tri- to hepta-PBDEs in the two lakes were different, possibly because of different input and remediation histories. The tri- to hepta-PBDE profiles were similar in the two lakes, with BDE-47 as the predominant congener, followed by BDE-99 and BDE-183. A different temporal trend for BDE-183 was found compared with other PBDEs, which is consistent with debromination of high-brominated PBDEs during sedimentation and aging. Methoxylated-PBDEs were detected only in Muskegon Lake (3.6 x 10 (-3) to 1.2 x 10(-1) ng/g dry wt). Methoxylated PBDEs showed different temporal trends compared with tri- to hepta-PBDEs. The differences in patterns of concentrations of MeO-PBDEs in the two lakes might be due to different aquatic communities in each lake. The occurrences of MeO-PBDEs could be the major source of hydroxylated polybrominated diphenyl ethers (OH-PBDEs) observed in organisms collected in these freshwater systems. Environ. Toxicol. Chem. 2011;30:1236-1242. 2011 SETAC

Abstract  Brominated flame retardants (BFRs) are synthetic organobromide compounds which inhibit ignition and combustion processes. Because of their immense ability to retard fire and save life and property, they have been extensively used in many products such as TVs, computers, foam, plastics etc. The five major classes of BFRs are tetrabromobisphenol-A (TBBPA), hexabromocyclododecane (HBCD), pentabromodiphenyl ether, octabromodiphenyl ether, and decabromodiphenyl ether. The last three are also commonly called PBDEs. BDE-85 and BDE-209 are the two prominent congeners of PBDEs and this study reports the adverse effects of these congeners in rodents. Exposure of rat sciatic nerves to 5 mu g/mL and 20 mu g/mL of BDE-85 and BDE-209 respectively lead to significant, concentration dependent reduction in nerve conduction function. Glucose absorption in the rat intestinal segments exposed to 5 mu g/mL of BDE-85 and BDE-209 was significantly reduced for both the compounds tested. Lastly, mice when exposed to 0.25 mg/kg body weight for four days showed a disruption in oxidant and antioxidant equilibrium. The tissues namely liver and brain have shown increase in the levels of lipid hydroperoxides indicating oxidative stress. Moreover, all the protective enzymes namely superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase, and glutathione S transferase (GST) have shown tissue specific alterations indicating the induction of damaging oxidative stress and setting in of lipid peroxidation in exposed animals. The results indicate monitoring of PBDEs in the environment is essential because levels as low as 5 mu g/mL and 0.25 mg/kg body weight were able to cause damage to the functions of rodents.

Abstract  Brominated flame retardants (BFRs) are a relatively new generation of chemicals used as flame retardants in many types of consumer products. The most commonly used BFRs include tetrabromobisphenol A, polybromodiphenyl ethers, polybromobiphenyls, and hexabromocyclododecanes. Perhaps as a result of their widespread use and their lipophilicity, these compounds have become ubiquitous in the environment. This review summarizes BFR concentrations determined in different environmental media. The main sources of BFRs and the exposure pathways through consumption of contaminated food, ingestion, and inhalation of dust are reviewed. The distribution patterns in the abiotic and biotic environment as well as their toxicity are discussed with a view to provide a better understanding of these emerging environmental pollutants. In addition, it is envisaged that this review will heighten the importance of identifying emerging issues and data gaps, and generate a future research agenda on BFRs.

Abstract  Brominated flame retardants (BFRs) are persistent and widespread chemicals. Therefore human beings are exposed to BFRs. House dust may be one source of exposure and contains a lot of xenobiotics in relatively high concentrations. In contrast to common GC-MS based methods here an online LC-MS/MS method is presented to quantify 16 BFRs in dust using ultrasonic solvent extraction as a single sample work up step. LOQ from 0.6 (tetrabromobisphenol A) to 80 (polybrominated diphenylethers (BDE 28) ng/g dust were achieved. Data for accuracy, precision and recovery are presented and are comparable to common LC-MS/MS methods in different matrices. In addition 5 real house dust samples were analyzed with high concentration (535 ng/g) for bis(2-ethyl-1-hexyl)tetrabromophthalate which is a novel alternative BFRs to replace common BDE's.

Abstract  This chapter provides a comprehensive review of the studies on persistent toxic substances (PTS) in the Philippines environment. Many of these persistent organic pollutants (POPs) including pesticides and industrial chemicals, which were either banned or restricted for use in most northern industrialized countries, are still in use in some developing countries. This review focuses on organochlorine compounds (OCs) such as dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), chlordane compounds (CHLs) and hexachlorobenzene (HCB) in the Philippines environment and biota. It also includes a review of residue levels of industrial chemicals such as polychlorinated biphenyls (PCBs), unintentional contaminants such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and also the new candidates of POPs, polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs). Environmental monitoring of POPs in the Asia-Pacific region, including the Philippines, revealed apparent POPs contamination particularly of PCBs and dioxins. Consequently, these studies suggest higher risk and exposure of the general populace to these toxic contaminants, more so for people residing near dumping site areas, where elevated concentrations of PCDD/Fs have been noted. PBDEs and HBCDs in human breast milk samples are widely present in general population of the Philippines as that of OCs. It can be presumed that PBDEs may become a major environmental concern in the Philippines as they were found at elevated levels in our work and were higher than in Japan, an industrially developed country. HBCDs were also higher than those reported in other available reports. Although decrease in POPs contamination may have been observed recently on a global scale, developing countries, such as the Philippines, may act as potential sources for certain contaminants for many more years. Therefore, a more systematic and continuous multi-media monitoring of these toxic substances in the Philippines seem imperative. Human health implications and toxic effects to wildlife must likewise be investigated.

Abstract  This paper presents precise sensitization test data of 15 chemicals with a wide spectrum of sensitization potencies, and proposes a new protocol and criteria for quantitative evaluation of sensitization potencies of chemicals. The tests were performed according to the design of Magnus-son and Kligman, changing the application concentrations for induction as well as for challenge phases. 3-dimensional relationships between mean response (or sensitization rate), induction and challenge concentrations were found in all chemicals tested. The following 2 values are proposed as a quantitative measure of sensitization potency: (a) the minimum induction concentration that induces a positive response; (b) the challenge concentration that induces a mean response approximately equal to 1.0 among the animals applied with the highest concentration for induction. Both values coincided with each other within the range of 1 order of magnitude in every compound except 2. The values varied by 5 orders or more of magnitude among the compounds, showing a wide variation of sensitization potencies among chemicals. A good correlation was found for every chemical between the value of sensitization potency thus obtained and the residual levels in causative products in human cases of allergic contact dermatitis. A new experimental protocol for obtaining values (a) and (b) is proposed.

Abstract  Brominated flame retardants are used in electronic appliances and textiles. They are detected in the environment and in breast milk in increasing concentrations. Their persistence is a matter of concern and poses a potential problem similar to that of polychlorinated biphenlys (PCBs). This report discusses these issues and future trends. Contents: characteristics of flame retardants; brominated flame retardant chemistry; analytical methods for brominated flame retardants; toxicology; environmental concentrations; future trends.

Abstract  The test article, hexabromocyclododecane (HBCD), in the vehicle, corn oil, was administered orally (gavage) to three groups of Crl:CD(SD)BR rats for 28 consecutive days. Dosage levels of 125, 350 and 1000 mg/kg/day were administered at a dose volume of 5 ml/kg. The treated groups consisted of 6 rats/sex in the 125 and 350 mg/kg/day groups and 12 rats/sex in the 1000 mg/kg/day group. A concurrent control group comprised of 12 rats/sex received the vehicle on a comparable regimen. Peameters that were evaluated included survival, clinical condition, body weights, food consumption, functional observational battery performance, motor activity, hematology and serum chemistry. At the conclusion of the four-week dosing period, 6 rats/sex/group were enthanized and necropsied. The remaining 6 rats/sex in the control and 1000 mg/kg/day groups were euthanized and necropsied following a two-week recovery period. Selected organs were weighed and/or preserved and selected tissues were examined microscopically for each animal. summer of 1981 to conduct an independent investigation to determine the effects of exposure to chromium compounds on human health and the environment. Battelle's study included a critical review of selected publications relating to chromina toxicity, a comprehensive survey of all 30 refractory plant locations in the United States, site visits to a representa- tive group of manufacturing plants, and an analytical assessment to determine if trivalent chromium compounds used in manufacturing refractories were con- verted to hexavalent materials during the manufacturing process.

Abstract  Brominated flame-retardant (BFR) additives are present in many polymeric consumer products at percent levels. High environmental concentrations have been observed near cities and polymer, textile and electronics manufacturing centers. Most studies have focused on European, North American and Asian locales. Releases are likely rising most dramatically in countries with weak environmental and human health regulation and enforcement, demand for electrical and electronic equipment (EEE) is escalating, and importation of waste EEE occurs. Several African countries meet these criteria, but little data are available on burdens or sources. To better understand the extent of BFR environmental dissemination in a southern African urban community, inland and coastal sediments were collected in the eThekwini metropolitan municipality, South Africa, and analyzed for polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB), 2-ethylhexyl 2,3,4,5-tretabromophalate (TBPH), 1,2-bis (2,4,6-tribromophenoxy) ethane (BTBPE) and decabromodiphenyl ethane (DBDPE). BFRs were detected in all samples (n=45). Concentration data are presented on total organic carbon (TOC) normalized basis. ΣBFR ranged from 114 to 47,100 ng g-1. Decabromodiphenyl ether was detected in 93% of samples (mean concentration 3208 ng g-1) followed by TBB at 91% (mean conc. 545 ng g-1). Durban Bay is strongly influenced by urban runoff and tidal hydrology and sediments therein exhibited ΣPBDE concentrations ranging from 1850 to 25,400 ng g-1 (median conc. 3240 ng g-1). These levels rival those in the heavily impacted Pearl River Delta, China. BFRs likely enter the South African environment during manufacture of BFR-containing products, during and following product use (i.e. after disposal and as a result of materials recycling activities), and from nonpoint sources such as atmospheric fallout and urban runoff. These results underline the need to investigate further the environmental burdens and risks associated with BFRs in developing countries.

Abstract  The concentration of hexabromocyclododecanes (HBCDs) in the environment media and organism samples are gradually rising with the increase of HBCDs usage. This study is designed to investigate the cytological effects of HBCDs on human hepatocyte L02 and explore the potential molecular mechanism. The results of CCK-8 assay showed that high concentration of HBCDs (>20 μM) significantly suppressed cell survival, while comparatively lower dose of HBCDs (10(-13)-10(-7)M) slightly stimulated cell proliferation (P < 0.05). In the mean time, high concentration HBCDs markedly induced cell apoptosis and DNA damage, accompanying with increase of intracellular Ca(2+)level and decrease of mitochondrial membrane potential (P < 0.05). ROS level induced by low concentration of HBCDs was comparatively lower than that by high concentration of HBCDs. In addition, low concentration HBCDs exposure (10(-13)-10(-7)M) resulted in up-regulation of PCNA protein expression level in a time-dependent manner. However, high concentration HBCDs exposure led to increase of Apaf-1 expression level. In conclusion, loss of mitochondrial membrane potential and activation of Apaf-1 mediated pathway involve the L02 cell apoptosis induced by high concentration HBCDs exposure. However, low concentration HBCDs exposure could stimulate cell proliferation of L02 cells, which might be associated with enhancement of PCNA expression.

Abstract  The concentrations and geographical distribution of hexabromocyclododecane (HBCD) were investigated in 37 composite surface sediments from seven major river drainage basins in China, including Yangtze River, Yellow River, Pearl River, Liaohe River, Haihe River, Tarim River and Ertix River. The detection frequency of HBCD was 54%, with the concentrations ranged from below limit of detection (LOD) to 206 ng/g dry weight. In general, the geographical distribution showed increasing trends from the upper reaches to the lower reaches of the rivers and from North China to Southeast China. Compared to other regions in the world, the average concentration of HBCD in sediments from Yangtze River drainage basin was at relatively high level, whereas those from other six river drainage basins were at lower or similar level. The highest HBCD concentration in sediment from Yangtze River Delta and the highest detection frequency of HBCD in Pearl River drainage basins suggested that the industrial and urban activities could evidently affect the HBCD distribution. HBCD diastereoisomer profiles showed that gamma-HBCD dominated in most of the sediment samples, followed by alpha- and beta-HBCD, which was consistent with those in the commercial HBCD mixtures. Further risk assessment reflected that the average inventories of HBCD were 18.3, 5.87, 3.92, 2.50, 1.77 ng/cm2 in sediments from Pearl River, Haihe River, Tarim River, Yellow River and Yangtze River, respectively.

Abstract  Brominated and chlorinated flame retardants were measured in about 40 samples of tree bark from 12 locations around the globe. The analytes were polybrominated diphenyl ethers (PBDE), Dechlorane Plus (DP), decabromodiphenylethane (DBDPE), hexabromocyclododecane (HBCD), hexabromobenzene (HBB), pentabromoethylbenzene (PBEB), pentabromobenzene (PBBz), and tetrabromo-p-xylene (pTBX). The highest concentrations of these compounds were detected at an urban site in Downsview, Ontario, Canada. Total PBDE and DP concentrations ranged from 2.1 to 190 ng/g lipid weight and from 0.89 to 48 ng/g lipid weight, respectively. Relatively high levels of DP (46 ± 4 ng/g lipid weight) were found at a remote site at Bukit Kototabang in Indonesia. The concentrations of total PBDE, DP, PBEB, and HBCD in the tree bark samples were significantly associated with human population in the nearby areas (r(2) = 0.21-0.56; P < 0.05). In addition, the concentrations of total PBDE and DP were significantly associated (r(2) = 0.40-0.64; P < 0.05). with the corresponding atmospheric concentrations of these compounds over a concentration range of 2-3 orders of magnitude.

Abstract  In Asian developing countries, large amounts of municipal wastes are dumped into open dumping sites each day without adequate management. This practice may cause several adverse environmental consequences and increase health risks to local communities. These dumping sites are contaminated with many chemicals including brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs). BFRs may be released into the environment through production processes and through the disposal of plastics and electronic wastes that contain them. The purpose of this study was to elucidate the status of BFR pollution in municipal waste dumping sites in Asian developing countries. Soil samples were collected from six open waste dumping sites and five reference sites in Cambodia, India, Indonesia, Malaysia, and Vietnam from 1999 to 2007. The results suggest that PBDEs are the dominant contaminants in the dumping sites in Asian developing countries, whereas HBCD contamination remains low. Concentrations of PBDEs and HBCDs ranged from ND to 180 μg/kg dry wt and ND to 1.4 μg/kg dry wt, respectively, in the reference sites and from 0.20 to 430 μg/kg dry wt and ND to 2.5 μg/kg dry wt, respectively, in the dumping sites. Contamination levels of PBDEs in Asian municipal dumping sites were comparable with those reported from electronic waste dismantling areas in Pearl River delta, China.

Abstract  In this study, zebrafish (Danio rerio) were exposed to two dietary concentrations of individual HBCD diastereoisomers (α-, β-, and γ-HBCD) for 42 days, followed by clean food for 21 days, to examine bioaccumulation, depuration, and enantiomer fractions (EFs) of HBCD diastereoisomers and to test the bioisomerization of HBCDs in fish. The depuration of α-, β-, and γ-HBCD in zebrafish followed the first-order process. Bioaccumulation parameters of the three diastereoisomers differed between low and high dose, suggesting that the bioaccumulation of them is concentration dependent. Calculated assimilation efficiencies (AEs), biomagnification factors (BMFs), and half-lives (t(1/2)) of α-HBCD were the highest among the three diastereoisomers. Furthermore, the study showed that zebrafish could biotransform γ-HBCD to α-HBCD. The highest AE, BMF, and t(1/2) of α-HBCD and bioisomerization of γ-HBCD to α-HBCD could explain why α-HBCD appears to be dominant in biota samples. The EFs for α- and γ-HBCD in zebrafish estimated at different times of bioaccumulation and depuration were all significantly greater than those in corresponding food (P < 0.05), indicating selective enrichment of (+) α-enantiomer and (+) γ-enantiomer relative to (-) α-enantiomer and (-) γ-enantiomer, respectively.

Abstract  AIM: Apply a recently developed expert elicitation procedure to evaluate the state of the current knowledge of the two brominated flame retardants (BFRs) most commonly used today; decabromo-diphenyl ether (decaBDE) and hexabromocyclododecane (HBCD) and their potential impact on human health in order to support policy considerations. This expert elicitation was organized by the HENVINET (Health and Environment Network) Consortium.

METHOD: The HENVINET expert elicitation procedure that was used in the evaluations of decaBDE and HBCD is a rapid assessment tool aimed at highlighting areas of agreement and areas of disagreement on knowledge-related key issues for environment and health policy decision making.

RESULTS: The outcome of the expert consultation on BFRs was concrete expert advice for policy makers with specific priorities for further action made clear for both stakeholders and policy makers. The experts were not in agreement whether or not the knowledge currently available on decaBDE or HBCD is sufficient to justify policy actions, but most experts considered that enough data already exists to support a ban or restriction on the use of these compounds. All experts agreed on the necessity of more research on the compounds. Priority issues for further research were, among others:• more studies on the extent of human exposure to the compounds.• more studies on the fate and concentration in the human body of the compounds.

Abstract  Brominated flame retardants, including hexabromocyclododecane (HBCD) and polybrominated diphenyl ethers (PBDEs) are used to reduce the flammability of a multitude of electrical and electronic products, textiles and foams. The use of selected PBDEs has ceased, however, use of decaBDE and HBCD continues. While elevated concentrations of PBDEs in humans have been observed in Australia, no data is available on other BFRs such as HBCD. This study aimed to provide background HBCD concentrations from a representative sample of the Australian population and to assess temporal trends of HBCD and compare with PBDE concentrations over a 16 year period. Samples of human milk collected in Australia from 1993 to 2009, primarily from primiparae mothers were combined into 12 pools from 1993 (2 pools); 2001; 2002/2003 (4 pools); 2003/2004; 2006; 2007/2008 (2 pools); and 2009. Concentrations of ∑HBCD ranged from not quantified (nq) to 19 ng g(-1)lipid while α-HBCD and γ-HBCD ranged from nq to 10 ng g(-1)lipid and nq to 9.2 ng g(-1)lipid. β-HBCD was detected in only one sample at 3.6 ng g(-1)lipid while ∑(4)PBDE ranged from 2.5 to 15.8 ng g(-1)lipid. No temporal trend was apparent in HBCD concentrations in human milk collected in Australia from 1993 to 2009. In comparison, PBDE concentrations in human milk show a peak around 2002/03 (mean ∑(4)PBDEs=9.6 ng g(-1)lipid) and 2003/04 (12.4 ng g(-1)lipid) followed by a decrease in 2007/08 (2.7 ng g(-1)lipid) and 2009 (2.6 ng g(-1)lipid). In human blood serum samples collected from the Australian population, PBDE concentrations did not vary greatly (p=0.441) from 2002/03 to 2008/09. Continued monitoring including both human milk and serum for HBCD and PBDEs is required to observe trends in human body burden of HBCD and PBDEs body burden following changes to usage.