► We studied pregnancy-related changes of PCBs, hydroxylated PCB, and PCP in blood. ► The results suggest a dilution of PCB and OH-PCB during pregnancy. ► Among some women OH-PCB levels increased at ...the end of pregnancy. ► Strong positive intra-individual correlations were only seen for PCBs. ► PCB body burdens during pregnancy can be assessed from a single short sampling period. ► OH-PCB and PCP analyses should be done during the exposure window of interest.
We studied pregnancy-related changes in serum concentrations of five polychlorinated biphenyls (PCBs, CB 118, CB 138, CB 153, CB 156, CB 180), three hydroxylated PCB metabolites (4-OH-CB107, 4-OH-CB146, 4-OH-CB187), and pentachlorophenol (PCP). Median serum lipid content increased 2-fold between early (weeks 9–13) and late pregnancy (weeks 35–36) (
N
=
10), whereas median PCB levels in serum lipids decreased 20–46%, suggesting a dilution of PCB concentrations in serum lipids. Nevertheless, strong positive intra-individual correlations (Spearman’s
r
=
0.61–0.99) were seen for PCBs during the whole study period. Thus, if samples have been collected within the same relative narrow time window during pregnancy, PCB results from one single sampling occasion can be used in assessment of relative differences in body burdens during the whole pregnancy period. Concentrations of OH-PCBs in blood serum tended to decline as pregnancy progressed, although among some women the concentrations increased at the end of pregnancy. Positive intra-individual correlations (
r
=
0.66–0.99) between OH-PCB concentrations were observed during the first and second trimester, whereas correlations with third trimester concentrations were more diverging (
r
=
−0.70–0.85). No decline in PCP concentrations was observed during pregnancy and no significant correlations were found between concentrations at different sampling periods. Our results suggest that for both OH-PCBs and PCP, sampling has to be more specifically timed depending on the time period during pregnancy that is of interest. The differences in patterns of intra- and inter-individual variability of the studied compounds may be due to a combination of factors, including lipid solubility, persistence of the compounds, distribution in blood, metabolic formation, and pregnancy-related changes in body composition and physiological processes.
Contamination of organochlorine pesticides (OCPs), polychlorinated diphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and their ...methylated counterparts (MeO-PBDEs) were determined in Black-crowned night heron (Nycticorax nycticorax) and Whiskered tern (Chlidonias hybrida) from two drinking water sources, e.g. Tianmu lake and East Tai lake in Yangtze River Delta, China. A novel PCBs contamination pattern was detected, including 11% and 6.9% highly chlorinated biphenyls (PCBs with eight to ten chlorines) in relation to total PCB concentrations in the Black-crowned night heron and Whiskered tern eggs, respectively. The predominating OCPs detected in the present study were 4,4′-DDE, with concentration range 280–650 ng g−1 lw in Black-crowned night heron and 240–480 ng g−1 lw in Whiskered tern, followed by β-HCH and Mirex. 6-MeO-BDE-90 and 6-MeO-BDE-99 are the two predominant congeners of MeO-PBDEs whereas 6-OH-BDE-47 contributes mostly to the OH-PBDEs in both species. Contamination level was considered as median or low level compared global data.
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•A number of POPs were determined in two water bird eggs from Yangtze River Delta.•Highly chlorinated biphenyls (CB194-209) were detected in all individual eggs.•4,4′-DDE was the predominant pesticide in all samples, followed by β-HCH and Mirex.•The exposure level of POPs was in the median or low level in the world.
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•Based on human and animal data, the review presents ADME data on CPs, and suggests further research needs.•Thousands of CP isomers are absorbed and accumulated in humans and ...wildlife.•Numerous CP metabolite reactions are suggested, of which chain shortening (CO2) and GSH conjugates are shown in vivo.•CPs are of major health concern but properties of CP metabolites, including their toxicity, are still unknown.•Future metabolism and toxicity studies of CPs are strongly encouraged.
Even though the chlorinated paraffins (CPs) have been on the environmental pollution agenda throughout the last 50 years it is a class of chemicals that only now is discussed in terms of an emerging issue with extensive annual publication rates. Major reviews on CPs have been produced, but a deeper understanding of the chemical fate of CPs, including formation of metabolites in animals and humans, is still missing. Thus, the present review aims to critically compile our present knowledge on the disposition, i.e. Adsorption, Disposition, Metabolism, and Excretion (ADME) of CPs in biota and to identify research needs.
We conclude that CPs could be effectively absorbed from the gastro-intestinal tract (GI) tract, and probably also from the lungs, and transported to various organs. A biphasic elimination is suggested, with a rapid initial phase followed by a terminal phase, the latter (e.g., fat tissues) covering half-lives of weeks and months. CPs are metabolized in the liver and excreted mainly via the bile and faeces, and the metabolic rate and type of metabolites are dependent on chlorine content and chain length. Results that strengthen CP metabolism are in vivo findings of phase II metabolites in bile, and CP degradation to carbon fragments in experimental animals. Still the metabolic transformations of CPs are poorly studied, and no metabolic scheme has yet been presented. Further, toxicokinetic mass balance calculations suggest that a large part of a given dose (not found as parent compound) is transformation products of CPs, and in vitro metabolism studies present numerous CP metabolites (e.g., chloroalkenes, chlorinated ketones, aldehydes, and carboxylic acids).
Environmental and human exposures to brominated flame retardants (BFR) have been of emerging concern since some BFR are persistent and bioaccumulative compounds. Among those, polybrominated diphenyl ...ethers (PBDE) have frequently been reported in low to high ng/g concentrations in human blood around the world while hexabromocyclododecane (HBCDD) only occasionally has been reported and then in the low ppb concentrations in human blood. The present study concerns PBDE congener and HBCDD concentrations in human milk from Stockholm from 1980 to 2004. HBCDD concentrations has increased four to five times since 1980 until 2002 but seems to have stabilized at this concentration in the last years (2003/04). Similarly, BDE-153 has continued to increase at least to 2001, after which it has stabilized in the mother's milk. Other PBDE congeners with four to five bromine substituents peaked 5 years earlier (1995) and are all decreasing. DecaBDE (BDE-209) is not a suitable biomarker for time trend studies according to the present results, showing no changes over time. This is likely due to its short apparent half-life in humans and poor transfer from blood to milk.
Air samples from a plant engaged in recycling electronics goods, a factory assembling printed circuit boards, a computer repair facility, offices equipped with computers, and outdoor air have been ...analyzed with respect to their content of brominated hydrocarbon and phosphate ester flame retardants. Polybrominated diphenyl ethers, polybrominated biphenyls, 1,2-bis(2,4,6-tribromophenoxy)ethane, tetrabromobisphenol A, and organophosphate esters were all detected in the indoor air samples, with the highest concentrations being detected in air from the recycling plant. In air from the dismantling hall at the recycling plant the average concentrations of decabromodiphenyl ether, tetrabromobisphenol A, and triphenyl phosphate were 38, 55, and 58 pmol/m3, respectively. Significantly higher levels of all of these additives were present in air in the vicinity of the shredder at the dismantling plant. This is the first time that 1,2-bis(2,4,6-tribromophenoxy)ethane and several arylated phosphate esters are reported to be contaminants of air in occupational settings. At all of the other sites investigated, low levels of flame retardants were detected in the indoor air. Flame retardants associated with airborne particles, present at elevated levels, pose a potential health hazard to the exposed workers.
Background
Novel brominated flame retardants (NBFRs) have been increasingly used as alternatives to legacy BFRs (e.g., PBDEs and HBCDs) in consumer products, but are liable to emigrate and ...contaminate indoor dust. In this study, a total of 154 house dust samples including floor dust (FD) and elevated surface dust (ESD) were collected in the biggest metropolitan area (Shanghai) of East China in 2016. Limited information about temporal variation of NBFRs indoors is available, while the period of sampling is influential in human exposure estimates. Levels, temporal variation, and human exposure of seven target NBFRs such as decabromodiphenylethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EHTBB), and bis(2-ethylhexyl) tetrabromophthalate (BEHTEBP) were investigated in indoor house dust.
Results
Concentrations of ∑
7
NBFRs ranged from 19.11 to 3099 ng/g with a geomean of 295.1 ng/g in FD, and from 34.74 to 404.6 ng/g with a geomean of 117.9 ng/g in ESD. The geomeans of DBDPE were 219.6 ng/g in FD and 76.89 ng/g in ESD, accounting for 90.5% and 80.5% of ∑
7
NBFRs. Levels of EHTBB, BTBPE, and DBDPE in FD exceeded significantly those in ESD. The temporal variation in ∑
7
NBFRs in FD was ranked as summer > winter > autumn > spring. The daily exposure doses (DEDs) of ∑
7
NBFRs via dust ingestion decreased as: infants > toddlers > children > teenagers > adults. Infants showed the highest DED in FD, 9.1 ng/kg bw/day.
Conclusions
DBDPE clearly dominated the NBFRs in both FD and ESD, but the concentrations of DBDPE in this study were generally moderate compared with the other international studies. Dust ingestion was the major pathway of human exposure to NBFRs indoors. About eightfold difference in exposure estimates between infants and adults showed that infants faced elevated exposure risks in FD. This study highlighted the necessity to estimate human exposure of NBFRs for different age groups using FD and ESD, respectively.
A method was developed for studies of the phototransformation at UV irradiation of aqueous solutions of tetrabromobisphenol A (TBBPA), tribromobisphenol A (TriBBPA), tetrachlorobisphenol A (TCBPA), ...2,4-dichlorophenol at various pHs as well as 2-chlorophenol, 2-bromophenol, 3,4-dichlorophenol and bisphenol A at pH 11. The absorbance spectra of the compounds and the emission spectra of the light-source were determined and used to calculate disappearance quantum yields of the photochemical reactions that were taking place. No major differences between the disappearance quantum yields of TBBPA and TCBPA were observed at pH 10, while the disappearance quantum yield of TriBBPA was approximately two times higher. The rate of decomposition of TBBPA was six times higher at pH 8 than at pH 6. Identification of the degradation products of TBBPA and TriBBPA, by GC–MS analysis and by comparison to synthesised reference compounds, indicated that TBBPA and TriBBPA decompose via different mechanisms. Three isopropylphenol derivatives; 4-isopropyl-2,6-dibromophenol, 4-isopropylene-2,6-dibromophenol and 4-(2-hydroxyisopropyl)-2,6-dibromophenol, were identified as major degradation products of TBBPA while the major degradation product of TriBBPA was tentatively identified as 2-(2,4-cyclopentadienyl)-2-(3,5-dibromo-4-hydroxyphenyl)propane.
Humans, independent on where they live, are exposed to complex and various mixtures of chemicals, including persistent organic pollutants (POPs). The variability of the exposure depends on sources of ...the chemicals and is influenced by e.g. geography, social and cultural heritage. While exposures to POPs are frequently studied in populations from developed industrial countries, very little is known on levels and trends of POPs in developing countries, especially in Africa.
The aim of the present study was to investigate levels and temporal trends of POPs in adults from Guinea-Bissau.
Serum samples were obtained from an open cohort of police officers in Guinea-Bissau. Repeated samples from 33 individuals were obtained at five time points between 1990 and 2007, in all 147 samples. Pooled serum samples were extracted and cleaned-up prior to analysis by gas chromatography and mass spectrometry. The concentration of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (4,4′-DDT) and its metabolites, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and hexachlorocyclohexanes (HCHs) were determined.
The major POP found in all samples was 1,1-dichloro-2,2-bis(4-chlorophenyl)ethene (4,4′-DDE) followed by 4,4′-DDT. 4,4′-DDE, 4,4′-DDT, PCBs and β- and γ-HCH were significantly decreasing over time. The PBDEs were found at low concentrations, with an increasing temporal trend for BDE-153.
National and international management may be behind the observed decreased organohalogen compound concentrations in humans from Guinea-Bissau from the early 1990's and onwards, similarly to the development of these compounds in humans from industrial countries. In contrast, PBDEs follow a trend of increasing concentrations even though at low levels.
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