Occurrence of polychlorinated biphenyls and polybrominated diphenyl ethers in belgian human adipose tissue samples

Hydrophobic carboxymethyl cellulose as a clean-up sorbent in the determination of nitrofuran metabolites in animal-fat samples

Hydrophobic carboxymethyl cellulose (CMC) biopolymers were fabricated for the removal of fat from food sample matrices. The hydrophobic CMCs were synthesised via the esterification of CMC with three alcohols with carbon chains of different lengths, methanol, butanol, and octadecanol, in the presence of sulfuric acid. The structure of the three synthesised hydrophobic CMCs was verified using FT-IR, and the physicochemical properties were investigated by TGA, SEM, and X-ray. Characterization confirmed the successful synthesis of the hydrophobic CMCs and that the hydrophobic groups are embedded in the sorbent biopolymer to interact with fat and reduce the fat content of the sample extract. Moreover, the performance of the fabricated hydrophobic CMCs was studied in two applications: fat removal and the determination of nitrofuran (NF) metabolites in fat samples. In the first application, excellent results were observed for fat removal; the highest percentage of fat removed from food sample extracts was 94.2% and the lowest was 88.5%. Successful results were also observed in the determination of NF metabolites in fat samples, as the final extract was clear and pure using the hydrophobic CMCs, while it was turbid for the control sample. In addition, the recovery of four NF metabolites was in the range of 97-117%. In general, the hydrophobic CMCs showed promising and satisfactory results, with CMC-C18 exhibiting the best results. The NF detection method was validated using CMC-C18 in three spiking levels; 0.5, 1.0 and 1.5 μg kg-1. The average recoveries of NF range between 83.3 to 104.3%, and the intra-day precision was determined by coefficient of variation, which was below 10% for all NF. The limit of detection and limit of quantification were between 0.6 to 0.9 and 0.20 to 0.28 μg kg-1 respectively. For linearity, the correlation coefficient (r2) was higher than 0.99 for NF metabolites. Overall, the hydrophobic CMCs can be further developed and safely used as green sorbents in food analysis applications.

The role of adipose tissue analysis on Environmental Pollutants Biomonitoring in women: The European scenario

Humans are exposed every day to assorted environmental pollutants namely, polychlorinated biphenyls (PCB), organochlorine pesticides (OCP), brominated flame-retardants (BFR), polycyclic aromatic hydrocarbons (PAH), synthetic musks, heavy metals (e.g. cadmium) and plastic additives (e.g. bisphenol A, BPA). Besides environmental persistence, biomagnification and bioaccumulative properties, these pollutants are classified as endocrine disruptors (EDs), metabolic disruptors, neurologic disruptors. These compounds affect the normal function of several mechanisms in the human body being linked to human health issues as cancer development (e.g. breast, uterine and endometrial), miscarriage, birth defects, premature delivery and infertility. In order to prevent future health issue of women and possible progeny, the assessment of EDs accumulated is essential, particularly in adipose tissue. These samples have been referred as the ideal matrix to establish over time accumulation and long-term exposure of persistent and non-persistent lipophilic EDs. However, the invasive sample collection procedure and methodology processing discourages the usage of this matrix for biomonitoring studies. In this review, a Web of Science search without any publishing year restriction on the analysis in adipose tissue of PCB, OCP, BPA, cadmium, BFR and synthetic musks was performed. A total of 313 studies were found, 158 were European studies from which the studies with data on women EDs accumulation were selected for detailed analysis (n = 90). The results were structured and presented in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The present paper is an overview on the existent EDs analytical methods and levels accumulated in women adipose tissue, with the correspondent health implications across Europe. The limits of detection and quantification were compared and a discussion with results obtained about the presence of ED was performed.

Polychlorinated biphenyl congener 180 (PCB 180) regulates mitotic clonal expansion and enhances adipogenesis through modulation of C/EBPβ SUMOylation in preadipocytes

PCB 180 is a typical non-dioxin-like polychlorinated biphenyl (NDL-PCB). It is one of the most prevalent PCB-congeners found in human adipose tissue. However, the role of PCB 180 in obesity remains poorly understood. The aim of this study was to explore the adipogenic effect and mechanism of PCB 180. Significant enhancement in adipogenesis was observed when differentiating murine 3T3-L1 preadipocytes or human preadipocytes-visceral (HPA-v) that were exposed to PCB 180. Furthermore, exposure to PCB 180 during the first two days was critical to the adipogenic effect. According to results from sequential cell cycle analyses, cell counting, BrdU incorporation, and cyclin D1, cyclin B1, and p27 protein quantification, PCB 180 was found to enhance mitotic clonal expansion (MCE) during early adipogenic differentiation. Molecular mechanistic investigation revealed that PCB 180 promoted accumulation of the C/EBPβ protein, a key regulator that controls MCE. Finally, it was found that PCB 180 mitigated degradation of the C/EBPβ protein by repressing the SUMOylation and subsequent ubiquitination of C/EBPβ by the upregulation of SENP2. In summary, it was shown for the first time that PCB 180 facilitated adipogenesis by alleviating C/EBPβ protein SUMOylation. This result provides novel evidence regarding obesogenic effect of PCB 180.

Evaluation of the Burdening on the Czech Population by Brominated Flame Retardants

The completed environmental study was concerned with assessing the exposure of the Czech population to polybrominated diphenyl ethers (PBDEs). Simultaneously, the levels of polychlorinated pollutants such as polychlorinated biphenyls (PCBs) and chlorinated diphenyl ethanes (DDTs) were also monitored. The pollutant levels were newly measured in solid fat tissue removed during plastic surgery. A total of 107 samples of fat were taken from 19–76-year-old volunteers. A total of 16 PBDE congeners were determined, of which only six occur in more than 38% of fat tissue samples. The total PBDE level attains an average value of 3.31 ng/g, which is 25% less than was measured in 2009. On the other hand, there was an increase in the levels of two PCB congeners, which was caused by an increase of the total PCB concentration from level of 625.5 ng/g, published in 2009, to the current level of 776 ng/g. The level of DDTs decreased and currently has a value of 467.4 ng/g, which is about 24% lower than in 2009. The contamination of obese middle-aged women in Czechia by more modern types of pollutants, such as PBDEs, is incomparably lower than that by PCBs and DDTs and is also decreasing in time.

Distribution of Organohalogen and Synthetic Musk Compounds in Breast Adipose Tissue of Breast Cancer Patients in Ulster County, New York, USA

We determined the concentrations of 98 halogenated organic compounds and synthetic musks in breast fat tissues of 50 breast cancer patients (age range: 34-77 years) collected during 1996-1998 in Ulster County, New York, USA. Polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated biphenyl 153 (PBB-153), polybrominated diphenyl ethers (PBDEs), and synthetic musk compounds (SMCs) were analyzed in breast fat tissues, and 46 analytes were found at a detection frequency of ≥ 65% and at concentrations in the decreasing order of OCPs > PCBs > SMCs > PBDEs > PBB-153. PCBs (median: 323 ng/g wet wt) and dichlorodiphenyltrichloroethanes (DDTs, median: 293 ng/g wet wt) were the major compounds found in breast fat tissues. Among PCB congeners, hexa- and hepta-chlorobiphenyls (60% of total PCBs) were the abundant ones. p,p'-DDE accounted for more than 99% of the total DDT concentrations. The concentrations of SMCs and PBDEs were 1-2 orders of magnitude lower than those of PCBs and DDTs. 1,3,4,6,7,8-Hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-r-2-benzopyran (median: 33 ng/g wet wt) was the most abundant SMC, whereas BDE-47 (median: 4.5 ng/g wet wt) was the most dominant PBDE congener present in breast tissues. A significant correlation (p < 0.05) between women's age and concentrations of DDTs, chlordanes, hexachlorobenzene and PCBs in breast tissues was found. Concentrations of PCBs, PBDEs, OCPs, and SMCs were not significantly different between malignant and benign tumor cases. This study adds baseline information on target tissue burdens of persistent organic contaminants in breast cancer patients.

The characteristics of pollution in the big industrial cities of Kazakhstan by the example of Almaty

BACKGROUND

Environmental pollution is a problem in the most industrial cities, including Almaty. These cities are frequently overpopulated and hazardous industrial facilities often have a negative impact on public health. The purpose of this study was to determine the characteristics of pollution in Almaty city and assess possible impact on a human by comparing obtained results with sanitary and hygienic standards. (Hygienic standards (HS) 2.1.7.2042-06. AAC of chemical substances in soil Russia). We used both local standards, such as ST RK 2011-2010 "Water, Food, Stern and Tobacco Products. Determination of Chlororganic Pesticides" and International Standards (Customs Union) Sanitary Regulations and Norms number 4630-88.

METHODS

The study was conducted by sampling air, water, and soil and subsequently analyzing them via laboratory and instrumental methods.

RESULTS

Heavy metals were detected via a high-precision method of atomic absorption spectroscopy. Noise was measured on location. Geographic regions with characteristic types of pollution were discovered. It was found that the main polluting factors were as follows: air pollution - carbon monoxide, suspended solids in the form of dust, lead, and noise; water - ammonium compounds, organic substances (assessed based on the chemical oxygen demand (COD) parameter), polychlorinated biphenyl (PCB); soil - lead and PCB. The amount of suspended solids in the air exceeded standard levels by as much as 13.6 times.

CONCLUSIONS

We visualized obtained data (using StatSoft Statistica v6.0 Rus and Exhibit 3.0 (MIT Simile Project) Softwares) for three districts of Almaty, which allowed us to compare the results efficiently. The results show the need for a detailed study on the optimization of the state of the environment and public health. Plans for further studies include development of a system that would enable reducing the negative impact of industrial facilities on public health and the environment in general.

PBDE emission from E-wastes during the pyrolytic process: Emission factor, compositional profile, size distribution, and gas-particle partitioning

Polybrominated diphenyl ether (PBDE) pollution in E-waste recycling areas has garnered great concern by scientists, the government and the public. In the current study, two typical kinds of E-wastes (printed wiring boards and plastic casings of household or office appliances) were selected to investigate the emission behaviors of individual PBDEs during the pyrolysis process. Emission factors (EFs), compositional profile, particle size distribution and gas-particle partitioning of PBDEs were explored. The mean EF values of the total PBDEs were determined at 8.1 ± 4.6 μg/g and 10.4 ± 11.3 μg/g for printed wiring boards and plastic casings, respectively. Significantly positive correlations were observed between EFs and original addition contents of PBDEs. BDE209 was the most abundant in the E-waste materials, while lowly brominated and highly brominated components (excluding BDE209) were predominant in the exhaust fumes. The distribution of total PBDEs on different particle sizes was characterized by a concentration of finer particles with an aerodynamic diameter between 0.4 μm and 2.1 μm and followed by less than 0.4 μm. Similarly, the distribution of individual species was dominated by finer particles. Most of the freshly emitted PBDEs (via pyrolysis) were liable to exist in the particulate phase with respect to the gaseous phase, particularly for finer particles. In addition, a linear relationship between the partitioning coefficient (K_P) and the subcooled liquid vapor pressure (P_L⁰) of the different components indicated non-equilibrium gas-particle partitioning during the pyrolysis process and suggested that absorption by particulate organic carbon, rather than surface adsorption, governed gas-particle partitioning.

Photodegradation behaviors of polychlorinated biphenyls in methanol by UV-irradiation: Solvent adducts and sigmatropic arrangement

This study has investigated the photolysis of polychlorinated biphenyls (PCBs) in methanol solution under UV irradiation. The results showed that the PCBs containing ortho-chlorine can generate both hydroxylated and methoxylated PCBs (HO-PCBs and MeO-PCBs), while the PCBs with a meta-chlorine but without ortho-chlorine can only generate MeO-PCBs as the only solvent adducts. No solvent adducts were detected during the photochemical reaction of 4-chlorobiphenyl (PCB-3), indicating the para-chlorine cannot be attacked by solvent molecule to form correspondent solvent adducts. The sigmatropic rearrangement was found during the photochemical reaction of ortho-substituted PCBs, but cannot occur in the reaction of PCBs with only meta- or para-chlorine, indicating that ortho-chlorine played a vital role in the sigmatropic rearrangement reaction. In addition, the seteric hindrance can also lead to the generation of sigmatropic rearrangement products. The effect of solvent was investigated in the case of photochemical reaction of 2-chlorobiphenyl (PCB-1), the results showed that sigmatropic rearrangement can occur in different solvents, and corresponding solvent adducts were generated in the photochemical reaction of PCB-1 in different solvents.

Airborne particle-bound brominated flame retardants: Levels, size distribution and indoor-outdoor exchange

The quality of indoor environments has a significant impact on public health. Usually, an indoor environment is treated as a static box, in which physicochemical reactions of indoor air contaminants are negligible. This results in conservative estimates for primary indoor air pollutant concentrations, while also ignoring secondary pollutants. Thus, understanding the relationship between indoor and outdoor particles and particle-bound pollutants is of great significance. For this reason, we collected simultaneous indoor and outdoor measurements of the size distribution of airborne brominated flame retardant (BFR) congeners. The time-dependent concentrations of indoor particles and particle-bound BFRs were then estimated with the mass balance model, accounting for the outdoor concentration, indoor source strength, infiltration, penetration, deposition and indoor resuspension. Based on qualitative observation, the size distributions of ΣPBDE and ΣHBCD were characterized by bimodal peaks. According to our results, particle-bound BDE209 and γ-HBCD underwent degradation. Regardless of the surface adsorption capability of particles and the physicochemical properties of the target compounds, the concentration of BFRs in particles of different size fractions seemed to be governed by the particle distribution. Based on our estimations, for airborne particles and particle-bound BFRs, a window-open ventilated room only takes a quarter of the time to reach an equilibrium between the concentration of pollutants inside and outside compared to a closed room. Unfortunately, indoor pollutants and outdoor pollutants always exist simultaneously, which poses a window-open-or-closed dilemma to achieve proper ventilation.

Dynamics of persistent organic pollutants in obese adolescents during weight loss

We have investigated the dynamics of various persistent organic pollutants (POPs) in the serum of 94 obese adolescents (34 boys and 60 girls: age range 11-19years) before (0M) and after 5months (5M) of undergoing weight loss treatment. Six groups of POPs, such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB) and polybrominated diphenyl ethers (PBDEs), were detected in all samples in the decreasing order of median levels: DDTs>PCBs>HCB>HCHs>CHLs>PBDEs. Levels and patterns of POPs between boys and girls at two time-points were similar. DDTs (0M/5M; median: 31/42ng/g lw) and PCBs (0M/5M; median: 17/28ng/g lw) were the major POPs. PCB 153 (0M/5M; 33/34% of the sum PCBs) was the most dominant PCB congener, followed by PCB 138 (0M/5M; 31/31%) and PCB 180 (0M/5M; 13/12%), respectively. The most important PBDE congeners were BDE 47 and 153, although total PBDE levels were low and ranged between 0.63 and 0.88ng/g lw. In general, levels of POPs in the obese adolescents were lower than previously reported in Belgian adolescents and adults. Due to weight loss, serum levels (except PBDEs) increased significantly thereafter combined with a body weight decrease (from 4 to 42kg). Serum concentrations increased by 1-3.5% per kilogram weight loss and 1-2.5% per BMI z-score loss for most POPs. To our knowledge, this is the first report on the dynamics of POPs in obese adolescents during weight loss. Lipid-soluble contaminants were released from adipose tissue into the blood leading to redistribution into the body. Whether the increase in the internal exposure to POPs may adversely influence health remains to be determined.

Organochlorine pesticides and polychlorinated biphenyls in human adipose tissue from northern Tunisia: Current extent of contamination and contributions of socio-demographic characteristics and dietary habits

The aims of the present study were to investigate the current exposure levels of persistent organochlorine compounds (OCs) in adipose tissues intraoperatively collected from 40 patients over 20 years undergoing non-cancer-related surgery residing in Northern region of Tunisia (Bizerte), which constitutes an exemplary case, and examined association between levels of contamination and both socio-demographic characteristics and dietary habits. Concentration of hexachlorobenzene (HCB), hexachlorocyclohexane isomers (α-HCH, β-HCH, γ-HCH and δ-HCH), dichlorodiphenyltrichloroethane isomers (p,p'-DDT and o,p'-DDT) and metabolites (p,p'-DDE, o,p'-DDE, p,p'-DDD and o,p'-DDD) and 12 polychlorinated biphenyls (PCBs) congeners were measured using capillary gas chromatography with electron capture detector. Overall, residue levels of OCs followed the decreasing order of DDTs > PCBs > HCB > HCHs. DDTs levels ranged from 74.49 to 1834.76ngg^-1 lipid and contributing to more than 90% to the sum of organochlorine pesticides (OCPs). p,p'-DDE was the most abundant in all samples and the p,p'-DDT/p,p'-DDE ratio (range between 1.85% and 58.45%) suggesting recent and ongoing exposure to banned commercial DDT products. PCB concentrations varied from 29.27 to 322.58ngg^-1 lipid and PCB-180, PCB-153 and PCB-138 were the dominant congeners accounting for 70% of total PCBs. We did not find significant correlations between OC exposure levels and sex, parity, habitat areas and smoking habits. In females, the adipose tissue concentrations of DDTs, HCB and PCB-118 were positively correlated with age. There was statistically significant relationship between body mass index (BMI) changes and the adipose tissue levels of HCB and HCHs. No association was found between OCPs levels and dietary factors. However, our study suggests that fish consumption may be an important contributor of PCBs adipose tissue content of PCBs in Tunisian people. The presented work is highly significant, being the first study pointing out the chronic exposure to OCs in Bizerte.

Autopsy tissues as biological monitors of human exposure to environmental pollutants. A case study: Concentrations of metals and PCDD/Fs in subjects living near a hazardous waste incinerator

Human biomonitoring is of tremendous importance to prevent potential adverse effects derived from human exposure to chemicals. Blood and urine are among the biological monitors more frequently used. However, biological matrices such as breast milk, hair, nails, saliva, feces, teeth, and expired air are also often used. In addition, and focused mainly on long-term exposure, adipose tissue and other human tissues like bone, liver, brain or kidney, are also used as biological monitors of certain substances, especially for long-term biomonitoring. However, for this kind of tissues sampling is always a limiting factor. In this paper, we have examined the role of autopsy tissues as biological monitors of human exposure to environmental pollutants. For it, we have used a case study conducted near a hazardous waste incinerator (HWI) in Catalonia (Spain), in which the concentrations of metals and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), have been periodically determined in autopsy tissues of subjects living in the area under potential influence of the facility. This case study does not show advantages -in comparison to other appropriate biomonitors such as blood- in using autopsy tissues in the monitoring of long-term exposure to metals and PCDD/Fs.

Brominated flame retardant emissions from the open burning of five plastic wastes and implications for environmental exposure in China

Based on the most widely used plastics in China, five plastic wastes were selected for investigation of brominated flame retardant (BFR) emission behaviors during open burning. Considerable variations were observed in the emission factors (EF) of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) from the combustion of different plastic wastes. Distribution of BFR output mass showed that ΣPBDE was emitted mainly by the airborne particle (51%), followed by residual ash (44%) and the gas phase (5.1%); these values for ΣHBCD were 62%, 24%, and 14%, respectively. A lack of mass balance after the burning of the plastic wastes for some congeners (output/input mass ratios>1) suggested that formation and survival exceeded PBDE decomposition during the burns. However, that was not the case for HBCD. A comparison with literature data showed that the open burning of plastic waste is major source of PBDE compared to regulated combustion activities. Even for state-of-the-art waste incinerators equipped with sophisticated complex air pollution control technologies, BFRs are released on a small scale to the environment. According to our estimate, ΣPBDE release to the air and land from municipal solid waste (MSW) incineration plants in China in 2015 were 105 kg/year and 7124 kg/year. These data for ΣHBCD were 25.5 and 71.7 kg/year, respectively. Considering the fact that a growing number of cities in China are switching to incineration as the preferred method for MSW treatment, our estimate is especially important. This study provides the first data on the environmental exposure of BFRs emitted from MSW incineration in China.

Mechanistic polychlorinated biphenyl exposure modeling of mothers in the Canadian Arctic: the challenge of reliably establishing dietary composition

BACKGROUND

Traditional food (TF) consumption represents the main route of persistent organic pollutant (POP) exposure for indigenous Arctic Canadians. Ongoing dietary transitions away from TFs and toward imported foods (IFs) may contribute to decreasing POP exposures observed in these groups.

METHODS

To explore this issue, we combined the global fate and transport model GloboPOP and the human food chain bioaccumulation model ACC-Human Arctic to simulate polychlorinated biphenyl (PCB) exposure in two indigenous Arctic Canadian communities from the Inuvik region, Northwest Territories and Baffin region, Nunavut. Using dietary survey information from initial (1996-98) and follow-up (2005-07) biomonitoring campaigns in Inuvik and Baffin, we simulated PCB exposures (PCB-118, -138, -153, and -180) for each individual study participant and also whole study populations.

RESULTS

TF intake rates, particularly of marine mammals (MMs), were the most important predictors of modeled PCB exposure, while TF consumption did not associate consistently with measured PCB exposures. Further, reported mean TF intake increased from baseline to follow-up in both Inuvik (from 8 to 183gd(-1)) and Baffin (from 60 to 134gd(-1)), opposing both the expected dietary transition direction and the observed decrease in human PCB exposures in these communities (ΣPCB Inuvik: from 43 to 29ngglipid(-1), ΣPCB Baffin: from 213 to 82ngglipid(-1)). However dietary questionnaire data are frequently subject to numerous biases (e.g., recall, recency, confirmation), and thus casts doubt on the usefulness of these data.

CONCLUSIONS

Ultimately, our model's capability to reproduce historic PCB exposure data in these two groups was highly sensitive to TF intake, further underscoring the importance of accurate TF consumption reporting, and clarification of the role of dietary transitions in future POP biomonitoring of indigenous Arctic populations.

Embryonic PCB exposure alters phenotypic, genetic, and epigenetic profiles in turtle sex determination, a biomarker of environmental contamination

In species with temperature-dependent sex determination, embryonic gonadal differentiation can be modified by exposure to exogenous chemicals such as environmental contaminants. Although phenotypic outcomes of such events are well documented, the underlying molecular mechanisms are rarely described. Here we examine the genetic and epigenetic effect of the embryonic exposure to polychlorinated biphenyls (PCBs) on gonad differentiation in red-eared slider turtles (Trachemys scripta). Some PCB congeners are without effect whereas others synergize to alter sex determination in this species. Application of two potent PCB congeners alter the physiological processes of gonad development normally dictated by the male-producing temperature (MPT), resulting sex ratios significantly biased toward female hatchlings. Of these PCB-induced females, oviduct formation is prominently distorted regardless of ovary development. Further, gonadal expression of ovarian markers, aromatase, FoxL2, and Rspo1, is activated whereas testicular markers, Dmrt1 and Sox9, are suppressed compared with typical expression patterns observed at MPT. DNA methylation profiles of the aromatase promoter in PCB-treated gonads do not follow the typical methylation pattern observed in embryos incubating at female-producing temperature. Rather, the MPT-typical methylation profiles is retained despite the induced ovarian formation. Overall, our studies demonstrate that PCB exposure alters the transcriptional profiles of genes responsible for gonadal differentiation but does not re-establish the epigenetic marks of the aromatase promoter normally set by incubation temperatures in embryonic gonads.

Distribution of persistent organic pollutants in two different fat compartments from obese individuals

There are only few studies defining persistent organic pollutant (POP) concentrations in various fat compartments from living obese individuals. The present study has therefore determined the concentrations of various classes of organohalogenated compounds, such as dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) in visceral fat (VF: n=52) and subcutaneous abdominal fat (SF: n=52) samples collected in 2010-2012 from obese individuals in Belgium. Organohalogen compounds were detected in all fat samples in the decreasing order of their concentrations: PCBs>DDTs>HCHs>CHLs>HCB>HBCDs>PBDEs, suggesting that Belgians have been widely exposed to these contaminants. The levels and the patterns of POP distribution in VF and SF tissue depots were not significantly different. Concentrations of PCBs (VF/SF; median: 285/275ng/g lw) and DDTs (VF/SF; median: 150/155ng/g lw) were the major POPs in all fat samples. Concerning PCBs, PCB 153 (VF/SF: 27/26%) was the most dominant congener, followed by PCB 180 (VF/SF: 17/18%), PCB 138 (VF/SF: 15/14.5%) and PCB 170 (VF/SF: 8.1/8.4%) to the sum PCBs, respectively. Levels of HBCDs (VF/SF; median: 4.0/3.7ng/g lw) and PBDEs (VF/SF; median: 2.6/2.7ng/g lw) were 1-2 orders of magnitude lower than those of PCBs and DDTs. Among PBDEs, BDE 153 (VF/SF: 31/34%) was the dominant congener, followed by BDE 47 (VF/SF: 26/23%), BDE 154 (VF/SF: 16/16%), BDE 100 (VF/SF: 10/11%) and BDE 99 (VF/SF: 9/9%). To our knowledge, this is the first report on HBCD concentrations in Belgian human fat tissues. Total PBDE and HBCD levels in human fat samples could not be correlated with age. In agreement with the literature, a significant correlation (p<0.05) between age and the concentration of PCBs (r=0.828), DDTs (r=0.640), HCHs (r=0.666), CHLs (r=0.534) and HCB (r=0.754), was observed in the present study. Levels of DDTs, HCHs, HCB and CHLs were also significantly correlated to each other, suggesting that they share similar exposure routes. Correlation with computed tomography (CT) scan data revealed that VF and VF/SF ratios are positive for most of the POPs, such as PCBs, PBDEs, p,p'DDE, CHLs, β-HCH, and HCB. To our knowledge, this study is the first to assess the relationship between POP levels in adipose tissue and markers of abdominal adiposity, determined by CT.

Understanding differences in the body burden-age relationships of bioaccumulating contaminants based on population cross sections versus individuals

BACKGROUND

Body burdens of persistent bioaccumulative contaminants estimated from the cross-sectional biomonitoring of human populations are often plotted against age. Such relationships have previously been assumed to reflect the role of age in bioaccumulation.

OBJECTIVES

We used a mechanistic modeling approach to reproduce concentration-versus-age relationships and investigate factors that influence them.

METHOD

CoZMoMAN is an environmental fate and human food chain bioaccumulation model that estimates time trends in human body burdens in response to time-variant environmental emissions. Trends of polychlorinated biphenyl (PCB) congener 153 concentrations versus age for population cross sections were estimated using simulated longitudinal data for individual women born at different times. The model was also used to probe the influence of partitioning and degradation properties, length of emissions, and model assumptions regarding lipid content and liver metabolism on concentration-age trends of bioaccumulative and persistent contaminants.

RESULTS

Body burden-age relationships for population cross sections and individuals over time are not equivalent. The time lapse between the peak in emissions and sample collection for biomonitoring is the most influential factor controlling the shape of concentration-age trends for chemicals with human metabolic half-lives longer than 1 year. Differences in observed concentration-age trends for PCBs and polybrominated diphenyl ethers are consistent with differences in emission time trends and human metabolic half-lives.

CONCLUSIONS

Bioaccumulation does not monotonically increase with age. Our model suggests that the main predictors of cross-sectional body burden trends with age are the amount of time elapsed after peak emissions and the human metabolic and environmental degradation rates.

High concentrations of polybrominated diphenylethers (PBDEs) in breast adipose tissue of California women

We measured major PBDEs and PCBs in breast adipose tissues of California women participating in a breast cancer study in the late 1990s. Samples were analyzed using gas chromatography with electron impact ionization and tandem mass spectrometry detection. The congener profile observed was: BDE47>BDE99>BDE153>BDE100>BDE154 and PCB153>PCB180>PCB138>PCB118. Whereas high correlations were observed within each chemical class, very weak correlations appeared between classes, pointing to different exposure pathways. Weak negative associations were observed for PBDE congeners and age. Our PBDE data are among the highest reported, exceeding data from the National Health and Nutrition Examination Survey and consistent with the high use of PBDEs in California. These data may be helpful in establishing a baseline for PBDE body burdens to gauge changes over time as a result of restrictions in the use of PBDE formulations.

Multivariate models to predict human adipose tissue PCB concentrations in Southern Spain

The use of Polychlorinated biphenyls (PCBs) has been severely restricted due to their high toxicity and persistency in the environment. However, the presence of PCBs in human tissues nowadays is still been reported worldwide. Background exposure predictors of the human PCB body burden require more precise understanding. In the present study, PCB congeners 138, 153, and 180 were quantified in adult adipose tissue samples (n=387) from Granada Province (Southern Spain) and data on potential predictors of PCB concentrations were gathered by questionnaire. Chemical analysis of the selected congeners was done by gas chromatography and mass spectrometry, and multivariate analyses were performed stratifying by gender. PCB residues were quantified in 92% (PCB 153), 90% (PCB 180), and 86% (PCB 138) of the population. Geometric mean concentrations were 161.65+/-4.41 ng/g lipid for PCB 153, 111.62+/-6.27 ng/g lipid for PCB 180, and 38.41+/-8.61 ng/g lipid for PCB 138. Multivariate models explained 30-36% of the variability in PCB concentrations. Age and body mass index (BMI) predicted exposure in both males and females and were positively correlated with the concentration of the three PCB congeners. Occupation and diet predicted exposure in the males, whereas only dietary predictors were observed in the females. Further in-depth studies are required to investigate the influence of dietary habits on the bioaccumulation of PCBs and to evaluate the impact of policies aimed at reducing human exposure.

Application of mass spectrometry in the analysis of polybrominated diphenyl ethers

This review summarized the applications of mass spectrometric techniques for the analysis of the important flame retardants polybrominated diphenyl ethers (PBDEs) to understand the environmental sources, fate and toxicity of PBDEs that were briefly discussed to give a general idea for the need of analytical methodologies. Specific performance of various mass spectrometers hyphenated with, for example, gas chromatograph, liquid chromatograph, and inductively coupled plasma (GC/MS, LC/MS, and ICP/MS, respectively) for the analysis of PBDEs was compared with an objective to present the information on the evolution of MS techniques for determining PBDEs in environmental and human samples. GC/electron capture negative ionization quadrupole MS (GC/NCI qMS), GC/high resolution MS (GC/HRMS) and GC ion trap MS (GC/ITMS) are most commonly used MS techniques for the determination of PBDEs. New analytical technologies such as fast tandem GC/MS and LC/MS become available to improve analyses of higher PBDEs. The development and application of the tandem MS techniques have helped to understand environmental fate and transformations of PBDEs of which abiotic and biotic degradation of decaBDE is thought to be one major source of Br(1-9)BDEs present in the environment in addition to direct loading from commercial mixtures. MS-based proteomics will offer an insight into the molecular mechanisms of toxicity and potential developmental and neurotoxicity of PBDEs.

Effects of decabrominated diphenyl ether (PBDE 209) on voltage-gated sodium channels in primary cultured rat hippocampal neurons

Polybrominated diphenyl ethers (PBDEs) are widely used as flame-retardant additives. But the application of PBDEs has been challenged due to their toxicity, especially neurotoxicity. In this study, we investigated the effects of decabrominated diphenyl ether (PBDE 209), the major PBDEs product, on voltage-gated sodium channels (VGSCs) in primary cultured rat hippocampal neurons. Employing the whole-cell patch-clamp technique, we found that PBDE 209 could irreversibly decrease voltage-gated sodium channel currents (I(Na)) in a very low dose and in a concentration-dependent manner. We had systematically explored the effects of PBDE 209 on I(Na) and found that PBDE 209 could shift the activation and inactivation of I(Na) toward hyperpolarizing direction, slow down the recovery from inactivation of I(Na), and decrease the fraction of activated sodium channels. These results suggested that PBDE 209 could affect VGSCs, which may lead to changes in electrical activities and contribute to neurotoxicological damages. We also showed that ascorbic acid, as an antioxidant, was able to mitigate the inhibitory effects of PBDE 209 on VGSCs, which suggested that PBDE 209 might inhibit I(Na) through peroxidation. Our findings provide new insights into the mechanism for the neurological symptoms caused by PBDE 209.

Examining the relationship between brominated flame retardants (BFR) exposure and changes of thyroid hormone levels around e-waste dismantling sites

Brominated flame retardants (BFRs) released from e-waste related activities may affect the health of local people. Assessing the impact of e-waste exposure during recycling and dismantling activities on local people's thyroid hormone levels is an area of ongoing research. During November and December 2008, the process of e-waste recycling and dismantling was investigated, and 236 occupation-exposed people and 89 non-occupation-exposed people approximate to the e-waste recycling sites were surveyed; their thyroid hormone levels (THs), thyrotropins (TSH) and BFRs levels in serum were assayed. Multiple regression models were constructed to analyze the changes of serum THs and TSH in the people living in the exposure area (exposure group) and the people in the control group. Covariates known to be or likely to be associated with THs, TSH and BFRs levels were analyzed. Lower level of Triiodothyronine (T(3)) in both occupation-exposed and non-occupation-exposed group were observed (p<0.01), when compared with the control group, and the same trend was obtained for free triiodothyronine (fT(3)) and free thyroxine (fT4) (p<0.01). However, no significant difference in thyroxine (T(4)) was found between the two groups. The level of TSH in the e-waste recycling occupational-exposed group ranged from 0.00 to 5.00microIU/ml with a mean of 1.26microIU/ml, whereas the level of TSH in the control group was from 0.03 to 5.54microIU/ml with a mean of 1.57microIU/ml. This study revealed that people having worked on e-waste recycling and dismantling had significantly lower TSH compared with the control group (p<0.01). Moreover, the level of BDE-205 is positively associated with the level of T4, as confirmed by the linear regression model (unstandardized regression coefficient, beta=0.25, rho=0.001) and a weaker positive relation was also found between the levels of BDE-126 and T4. Meanwhile, a weak negative relation was found between the levels of PBB 103 and T3, and between the levels of fT3 and fT4. These results suggest that exposure to BFRs released from primitive e-waste handling may contribute to the changes of THs and TSH levels.

Concentrations of polybrominated diphenyl ethers in breast milk correlated to maternal age, education level, and occupational exposure

The aim of the present study is to determine whether levels of polybrominated diphenyl ethers in breast milk in the general population are associated with demographic parameters, socioeconomic status, lifestyle factors, and occupational exposure. Forty-six participants are randomly selected from healthy women recruited between April 2007 and April 2008 from local hospitals in southern Taiwan. Thirty PBDE isomers in breast milk are analyzed using a gas chromatograph with a high resolution mass spectrometer. The mean+/-standard deviation of Sigma PBDEs in breast milk is 3.59+/-1.07 ng/g lipid. Our current value of Sigma PBDEs in breast milk is 0.7-fold lower compared to the past value in our previous study between 2000 and 2001. Higher levels of Sigma PBDEs might be significantly associated with older maternal age and maternal age of the present study is between 22 and 42 years old. Levels of Sigma PBDEs and certain PBDEs in breast milk are not correlated with maternal pre-pregnant BMI (Body mass index), parity, and lipid contents of breast milk. The Sigma PBDEs level in breast milk is lower in more educated women after controlling for age and pre-pregnancy BMI in our subjects. The main factors associated with Sigma PBDEs in breast milk are age and education level among the binary variables of demographic, socioeconomic, and lifestyle characteristics in this report. The exploratory relationships are found between PBDEs in breast milk and age, education level, or occupational exposure due to small sampling size.

Polybrominated diphenyl ethers, polychlorinated naphthalenes and polycyclic musks in human fat from Italy: comparison to polychlorinated biphenyls and organochlorine pesticides

Prior to this study, reports of occurrence of polycyclic musks and polychlorinated naphthalenes (PCNs) in human tissues from Italy were not available. In this study, concentrations of PCNs and polycyclic musks were determined in human adipose tissue from Italy collected during 2005-2006; for comparison, legacy organohalogen pollutants such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were determined. SigmaPCN concentrations ranged from 0.5 to 14 ng/g lipid wt (lw). Polycyclic musks such as HHCB and AHTN were found in 92% and 83% of the human samples, respectively. Concentrations of PBDEs in Italian adipose tissue ranged between 3.2 and 35.6 ng/g lw.

Dual body burdens of polychlorinated biphenyls and polybrominated diphenyl ethers among local residents in an e-waste recycling region in Southeast China

E-waste recycling resulted in serious pollution of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in Taizhou of Zhejiang Province, China. The aims of this study were to assess dual body burdens of the two pollutants and potential health risk for local residents. Blood samples were collected from two e-waste recycling sites, Luqiao (where PCBs-containing e-wastes were recycled) and Wenling (where PBDEs-containing e-wastes were recycled). The mean summation SigmaPCBs (CB-105, 118, 153, 183, and 180) and summation SigmaPBDEs (BDE-28, 47, 99, 100, 153, 154, 180, and 209) were 204.20 and 117.58 ng g(-1) lipid in the blood from Luqiao, respectively, while they were 83.80 and 357.44 ng g(-1) lipid from Wenling, respectively. The PCBs levels among Luqiao residents were comparable to the values reported for US populations, while the PBDEs levels among two study populations were higher than the values from US populations. This is the first report to present dual body burdens of PCBs and PBDEs at so high levels. Based on previous epidemiologic data, it is suggested that dual burdens of PCBs and PBDEs at so high levels might pose health risk for local residents. In addition, no correlation between PCBs or PBDEs concentrations and the ages of the volunteers was observed in the two populations, which was explained by similar exposure time. No correlation of PBDEs with PCBs concentrations suggested different pathways of human exposures to PCBs and PBDEs. Our findings have raised concern about human health risk of dual exposure to PCBs and PBDEs resulting from e-waste recycling.

Burdens of PBBs, PBDEs, and PCBs in tissues of the cancer patients in the e-waste disassembly sites in Zhejiang, China

This study was conducted to explore the burdens of PBBs, PBDEs, and PCBs among cancer patients living in the e-waste disassembly sites. The contents of 23 PBB congeners, 12 PBDE congeners, and 27 PCB congeners in kidney, liver, and lung samples were measured by GC-MS. The results showed that low-brominated PBBs and PBB153 were the predominant congeners. PBDE47 were the most predominant PBDE congeners. PBDE209 were detected in > 70% of the samples, with geometric means ranging from 64.2 to 113.9 ng g(-1) lipid. Among the three subfamilies of PHAHs, PCB concentrations were the highest. The detected levels of PHAHs were in the same order of magnitude in the three tissues, which indicated that any of the three tissues could be the suitable indicator for assessing body burdens of PHAHs. PBB contents (181-192 ng g(-1) lipid) were obviously higher than those reported in the general USA population (3-8 ng g(-1) lipid). PBDE levels (174.1-182.3 ng g(-1) lipid) were comparable to those reported in the USA population, but significantly higher than those of the European population. PCBs levels were comparable to those of the European population. The high cancer incidence in the disassembly sites may be related to higher burdens of PBBs, PBDEs, and PCBs in tissues.

Multimedia modeling of polybrominated diphenyl ether emissions and fate indoors

We adapted an indoor multimedia fugacity model to consider emissions and fate of polybrominated diphenyl ethers (PBDEs) and to understand the variability of indoor concentrations. The model was applied to an office in which an 80% decrease in PBDE air concentration was observed after an old computer was exchanged with a newer one. PBDE-impregnated polyurethane foam (PUF) and carpet were treated as pseudo-steady-state components with specified fugacities derived from measured concentrations of 173 and 2140 ng x g(-1), respectively. Emission rates of 35 and 5.4 ng x h(-1), for the old and new computers, respectively, were calculated using the pseudo-steady-state approach. Particle movement (deposition and resuspension) dominates within-room transport processes, and dust removal (vacuuming) and air advection (ventilation) are the main loss processes. The most sensitive parameters to air concentrations and estimated emission rates are room temperature, particle concentrations and deposition velocity, and air exchange rates. The air exchange rates and bouncing on PUF furniture can alter whether the PUF and carpet are sources or sinks of PBDEs. Model results suggest that exposure via air can be reduced by removing dust, having a high air exchange rate, and low indoor temperatures.

Brominated flame retardants and other organochlorine pollutants in human adipose tissue samples from the Czech Republic

Brominated flame retardants (BFRs) represented by polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) together with major persistent organochlorine pollutants, polychlorinated biphenyls (PCBs) and selected organochlorine pesticides (OCPs), were determined in adipose tissue samples (n=98) obtained by liposuction of Czech subjects. Compared to other organochlorine pollutants (mostly PCBs and DDTs), levels of PBDE were lower by 2 orders of magnitude ranging from 0.2 to 54.3 ng/g lipid weight. PBDE congeners No. 47, 99, 153 and 183 were the most abundant constituting up to 90% of these pollutants in adipose tissue. The PBDEs content measured in this study was comparable with data reported in similar samples collected in Spain, Sweden, Belgium and Japan, whilst slightly lower than in the United States. Regarding PCBs, the dominating congeners were No. 138, 153 and 180 representing up to 90% of indicator congeners. The levels of PCBs were similar to those found in other European countries. While no age dependency was found for PBDEs, an increase of PCB and OCP levels with age was observed. Different exposure routes of donors were documented by the absence of the relationship between PCBs and OCPs.

Assessment of current serum levels of PCDD/Fs, dl-PCBs and PBDEs in a Dutch cohort with known perinatal PCDD/F exposure

As part of a longitudinal cohort study, now in its second decade, we determined PCDDs/Fs dl-PCBs and PBDEs in serum of adolescents with known perinatal PCDD/F exposure. Of the original cohort, 33 adolescents aged 14-19 years, who had been studied previously during their neonatal (n=60), toddler and pre-pubertal period (n=41) agreed to participate in the current follow-up. PCDD/F-, dl-PCB- and PBDE congeners were measured using GC/MS. Current serum levels of PCDD/Fs determined in our cohort were relatively low (mean of 2.2 pg/g) compared to the perinatal exposure. No correlation between perinatal exposure and current serum PCDD/F was found. Planar PCB TEQ levels were 2.2 pg/g. Current summation operatorPBDE levels were 8.7 ng/g lipid. There was one outlier with a summation operatorPBDE of 74 ng/g lipid. The presence of this high value indicates that the exposure pathway is different from PCDD/F and PCB, most likely by dust and food contaminated with dust. Concluding we can say that current PCDD/F levels are quite low compared to the perinatal PCDD/F exposure of the cohort. PBDE levels however are relatively high compared to other European countries, more research on possible health effects of these levels, especially for subjects with outlier concentrations, should be performed.

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in human liver and adipose tissue samples from Belgium

Levels of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in paired human adipose tissue and liver samples (n=25) from Belgium. Average concentrations and standard deviation of sum PBDEs (congeners 28, 47, 99, 100, 153, 154 and 183) were 5.3+/-3.0 (range 1.4-13.2) and 3.6+/-2.1 (range 1.0-10.0)ng g(-1) lipid weight (lw) in adipose tissue and liver, respectively. These concentrations were similar to reported PBDE data from Belgium and were at the lower end of the concentration range reported elsewhere in the world. In both tissues under study, BDE 153 and BDE 47 were the most abundant PBDE congeners, contributing approximately 35% and 25% to the total PBDE content. Average concentrations and range of PCBs (sum of 23 congeners) were 490 (range 70-1130) and 380 (range 90-1140)ng g(-1)lw in adipose tissue and liver, respectively. No correlation between age and concentrations of PBDEs could be found (r=0.04), while PCB concentrations correlated significantly with age (r=0.62, p<0.01, for the sum PCBs; r=0.64, p<0.01 for PCB 153 alone). Factors, such as exposure pathways (food, dust and air), rates of bioaccumulation, metabolism and elimination, influence the concentrations of PBDEs differently than those of PCBs in humans.

Human internal and external exposure to PBDEs--a review of levels and sources

This paper reviews the existing literature on human exposure to polybrominated diphenyl ethers (PBDEs), with particular focus on external exposure routes (e.g. dust, diet, and air) and the resulting internal exposure to PBDEs (e.g. breast milk and blood). Being lipophilic and persistent organic compounds, PBDEs accumulate in lipid-rich tissues. Consequently, food items like fish from high trophic levels or lipid-rich oils have been found to contain relatively high concentrations of PBDEs, thus presenting an important exposure pathway to humans. The presence of PBDEs in various products of everyday use may lead to some additional exposure in the home environment. Dust seem to be an aggregate of the indoor source, and the ingestion of dust conveys the highest intake of BDE-209 of all sources, possibly also of other PBDE congeners. The PBDE exposure through dust is significant for toddlers who ingest more dust than adults. Infants are also exposed to PBDEs via breast milk. Internal human exposure has generally been found to be one order of magnitude larger in North America than in Europe and Asia. These differences cannot solely be explained by the dietary intake as meat products are the only food group where some differences has been observed. However, indoor air and dust concentrations have been found to be approximately one order of magnitude higher in North America than in Europe, possibly a result of different fire safety standards. Within Europe, higher PBDE concentrations in dust were found in the UK than in continental Europe. Recent studies have shown that BDE-209 also accumulates in humans. A shift in congener composition from maternal to umbilical cord blood has been observed in several cases. A shift has also been observed for BDE-209, which is present in larger ratios in umbilical cord blood and in particular in placenta than in maternal blood.

Polybrominated diphenyl ethers in leaves and soil from typical electronic waste polluted area in South China

Polybrominated diphenyl ethers (PBDEs) in leaves and soil from typical e-waste polluted area in South China were investigated. The concentrations (ng/g dry weight) of PBDE congeners and summation operatorPBDE of five leaf samples were much lower than those in soil sample. The general patterns of summation di-BDEs to summation hepta-BDEs percentage distribution in leaf samples were similar to those of the soil sample, except the percentage of BDE209 which were lower than in soil. The percentages of summation di-BDEs to summation hepta-BDEs in soil were in the range of those in leaf samples. The results showed that the contamination of PBDEs in the leaf samples had good correlation with the soil around them.

Photolysis of mono- through deca-chlorinated biphenyls by ultraviolet irradiation in n-hexane and quantitative structure-property relationship analysis

The photolysis of 16 polychlorinated biphenyls (PCBs) (including mono- through deca-chlorinated) in n-hexane was investigated under ultraviolet irradiation using a 500-W high-pressure mercury lamp. Photolysis of PCBs follows pseudo-first-order reaction kinetics, with photolysis rate constants ranging between 0.0011 s(-1) for PCB-52 and 0.0574 s(-1) for PCB-118. The degradation rates of PCBs by high-pressure mercury lamp irradiation were remarkably independent with respect to the degree of chlorination. Furthermore, partial least squares (PLS) models were developed to provide insight into which aspect of the molecular structure influenced PCB photolysis rate constants. It was found that the photolysis rates of PCBs increased with an increase in the net charge on the carbon atom (qc), (E(LUMO)-E(HOMO))2, and the Y-axis dipole moment (mu(y)) values, or the decrease in the energy of the second highest occupied molecular orbital (E(HOMO-1)), energy of the lowest unoccupied molecular orbital (E(LUMO)), E(LUMO) + E(HOMO), E(LUMO)--E(HOMO), most positive atomic charge (q+), and the twist angle of the chlorine atom (TA) values.

Polybrominated diphenyl ethers as endocrine disruptors of adipocyte metabolism

OBJECTIVE

Obesity is thought to result from poor diet and insufficient exercise. An additional factor may be endocrine-disrupting environmental chemicals that contaminate the air, water, and food supply. We tested the hypothesis that a class of lipid-soluble flame retardant chemicals known to accumulate in adipose tissue, polybrominated diphenyl ethers (PBDEs), disrupts insulin and isoproterenol sensitivity of isolated rat adipocytes.

RESEARCH METHODS AND PROCEDURES

Six-week-old Sprague-Dawley rats were gavaged daily with 14 mg/kg body weight (BW) pentabrominated diphenyl ether (penta-BDE) in corn oil (n = 24) or corn oil alone (n = 24). At 2 and 4 weeks of treatment, epididymal fat pad adipocytes were isolated, and isoproterenol-stimulated lipolysis, insulin-stimulated glucose oxidation, and adipocyte size were measured.

RESULTS

There was no alteration in adipocyte metabolism after 2 weeks of in vivo penta-BDE treatment, but after 4 weeks of treatment, adipocytes averaged a 30% increase in isoproterenol-stimulated lipolysis and a 59% decrease in insulin-stimulated glucose oxidation, compared with control. There were no differences in average rat BW and adipocyte size between treated and control rats, but plasma total thyroxine level in 2- and 4-week treated rats was 30% of control.

DISCUSSION

Daily exposure of rats to 14 mg/kg BW penta-BDE for 4 weeks has no effect on animal or adipocyte size but significantly alters insulin and isoproterenol-stimulated metabolism of isolated adipocytes. These alterations, hallmark features of metabolic obesity, suggest the need for further research on the contribution of lipid-soluble, endocrine-disrupting environmental chemicals to the obesity epidemic.

Determinants of prenatal exposure to polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in an urban population

BACKGROUND

Recent studies have reported blood levels of polybrominated diphenyl ethers (PBDEs) in the U.S. population. Information about neonatal levels and about the relationship to polychlorinated biphenyls (PCBs) exposures is limited.

OBJECTIVES

The objective was to characterize levels and determinants of fetal exposure to PBDEs and PCBs among newborns from Baltimore, Maryland.

METHODS

We analyzed umbilical cord blood for eight PBDEs and 35 PCBs from infants delivered at the Johns Hopkins Hospital. Maternal and infant characteristics were abstracted from medical records.

RESULTS

Ninety-four percent of cord serum samples had quantifiable levels of at least one PBDE congener, and > 99% had at least one detectable PCB congener. PBDE concentrations in cord blood were similar to those reported in other studies from North America. Strong correlations were observed within but not across PCB and PBDE classes. Multivariate models showed that many factors independently predicted exposure to BDE-47, BDE-100, and BDE-153 and CB-118, CB-138/158, CB-153, and CB-180. Generally, infants of Asian mothers had lower PBDE and PCB levels, and infants of smokers had higher levels. Increased maternal body mass index was associated with lower levels of PCBs but not PBDEs. Levels of PCBs but not PBDEs were lower in births from married and multiparous mothers. Increased maternal age was associated with higher PCB levels but lower PBDE levels.

CONCLUSIONS

Although many of the factors we investigated were independent predictors of both PBDE and PCB levels, in some cases the direction of associations was different. More research is needed to better understand the sources and pathways of PBDE exposure.

Polybrominated diphenyl ethers and persistent organochlorines in Japanese human adipose tissues

The present study determined concentrations of polybrominated diphenyl ethers (PBDEs) and persistent organochlorines (OCs) in Japanese human adipose tissues collected during 2003-2004. Concentrations of PBDEs in adipose tissues were 1-2 orders of magnitude lower than those of OCs. However, observed PBDE congener levels in this study were relatively higher than those in Japanese human adipose tissues collected during 2000 reported previously, while OC levels were comparable to those in specimens collected during 1999 reported by our group. In addition, no age-dependent accumulation of PBDEs was observed, while OC levels except chlordane compounds increased with age. These results indicate recent human exposure to PBDEs in Japan. Among PBDE congeners accumulated in Japanese adipose tissues, BDE-153 was dominant, but this trend was different from those in human milk (BDE-47) and blood (BDE-209) reported previously in Japan, implying the congener-specific kinetics in human bodies. The significant positive correlations between PBDEs and OCs were observed in Japanese adipose tissues, indicating the similar exposure route of these contaminants for Japanese citizens, probably via fish intake.

Plasma concentrations of selected organobromine compounds and polychlorinated biphenyls in postmenopausal women of Québec, Canada

BACKGROUND

Brominated flame retardants, especially polybrominated diphenyl ethers (PBDEs), have been widely used in North America, but little is known about the level of exposure of human populations to these compounds.

OBJECTIVES

We set out to assess the internal exposure of postmenopausal Canadian women to selected organobromine compounds and to investigate factors associated with this exposure.

METHODS

We measured concentrations of four PBDEs, one polybrominated biphenyl, and for comparative purposes, 41 polychlorinated biphenyl (PCB) congeners in plasma samples from 110 healthy postmenopausal women who were recruited at a mammography clinic in 2003-2004.

RESULTS

PBDE-47 was the major PBDE congener, with a mean (geometric) concentration of 8.1 ng/g lipids and extreme values reaching 1,780 ng/g. By comparison, the mean concentration of the major PCB congener (PCB-153) was 41.7 ng/g and the highest value was 177 ng/g. PBDEs 47, 99, and 100 were strongly intercorrelated, but weaker correlations were noted with PBDE-153. As the sum of PBDEs (summation operatorPBDEs) increased, the relative contribution of PBDE-47 to the summation operatorPBDEs increased, whereas that of PBDE-153 decreased. PBDE-153 was the only brominated compound correlated to PCB-153. PBDE levels were not linked to any sociodemographic, anthropometric, reproductive, or lifestyle variables documented in the present study. Age and body mass index gain since the age of 18 years were significant predictors of PCB-153 plasma levels.

CONCLUSION

Our results suggest that exposure to PBDE-47 likely occurs through direct contact with the penta-PBDE formulation, whereas exposure to PBDE-153 may originate in part from the food chain.

Development and application of a simplified clean-up procedure for the determination of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in horse fat by gas chromatography-tandem mass spectrometry (GC-MS/MS)

A simplified clean-up procedure was developed in combination with gas chromatography-tandem mass spectrometry (GC-MS/MS) for the determination of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in adipose tissue. Clean-up was performed by the successive application of a Mega Bond Elut silica column and a Bond Elut PCB column. Validation of the method was conducted according to European Union Commission Decision 2002/657/EC. In order to evaluate the applicability of the method, 44 horse fat samples were analysed. The total PCB concentration (sum of PCBs 28, 52, 101, 118, 138, 153 and 180) ranged from 5.35 to 140 ng g(-1) lipid weight. The total PBDE concentration (sum of BDEs 28, 47, 99, 100, 153, 154 and 183) ranged from below the decision limit to 6.34 ng g(-1) lipid weight.