Polybromodiphenyl Ethers Research Articles

Analysis of major congeners of polybromobiphenyls and polybromodiphenyl ethers in office dust using high resolution gas chromatography–mass spectrometry

The study focused on analysis of polybromobiphenyls (PBBs) and polybromodiphenyl ethers (PBDEs) congeners in office dust obtained in Pretoria, South Africa. Of the 32 congeners considered for identification, (BB-1, 2, 4, 10, 15, 26, 29, 30, 31, 38, 49, 80, 103, 153, 155, 209 and BDE-3, 15, 17, 28, 47, 66, 77, 85, 99, 100, 126, 138, 153, 154, 183, 209) only BB-2, 4, 30, 153, 209 and BDE-47, 66, 85, 99, 153 and 209 congeners were detected. The sum of PBBs concentration detected in office dust ranged from <dl−196ngg−1 dry weight (dw) with a median and mean of 11.4 and 38.2ngg−1, respectively. On the other hand, the sum of PBDEs concentration detected ranged from 21.6 to 578.6ngg−1dw with a median and mean of 162 and 169ngg−1dw, respectively. A Spearman rank correlation between ∑5PBBs and ∑6PBDEs (rs=0.55, p=0.003), indicated a statistical significant positive correlation for the similarity of pollution sources for both compound classes. However, no correlation was observed between the number of electronic materials and summation of concentrations of PBBs and PBDEs congeners detected. Concentrations of PBDEs detected in this study are substantially lower than reported in office dust in developed countries.

Heating of BDE-209 and BDE-47 in plant oil in presence of o,p′-DDT or iron(III) chloride can produce monochloro–polybromo diphenyl ethers

Heating processes of food can alter the concentrations and composition of organohalogen compounds. In this study the fate of two polybrominated diphenyl ether (PBDE) congeners, decabromodiphenyl ether (BDE-209) and 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) was analyzed when heated in plant oil with and without additional compounds. When the PBDEs were heated in pure plant oil, no transformation was observed. Heating of decabromodiphenyl ether (BDE-209) together with ortho,para′-dichlorodiphenyltrichloroethane (o,p′-DDT) or iron(III) chloride in plant oil resulted in the formation of monochloro–nonabromodiphenyl ethers (Br9Cl-DEs). Almost 10% of the initial amount of BDE-209 was transferred into Br9Cl-DEs. Heating BDE-47 in the presence of iron(III) chloride produced two monochlorinated transformation products which were tentatively identified as 2,2′,4-tribromo-4′-chlorodiphenyl ether (4′-Cl-BDE-17) and 2,4,4′-tribromo-2′-chlorodiphenyl ether (2′-Cl-BDE-28). However, the reactivity was smaller and no Br→Cl exchange was observed with o,p′-DDT. The conditions used in our experiments (200°C; heating 30min–3h) indicate that such reactivity may also occur during cooking of fish, meat and other food samples.

Emerging Brominated Flame Retardants in the Sediment of the Great Lakes

The concentrations of 13 currently used brominated flame retardants (BFRs) were analyzed in 16 sediment cores collected from the North American Great Lakes. Among them, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), hexabromocyclododecane (HBCD), 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH), and hexachlorocyclopentadienyl dibromocyclooctane (HCDBCO) were more frequently detected than others. In general, these emerging BFRs have much lower concentrations than polybromodiphenyl ethers (PBDEs) and dechloranes. Inventories of the five BFRs named above, given on a logarithm basis, were found to decrease linearly with the increasing latitude of the sampling locations, but with weaker statistics than those previously reported for the dechloranes. Logarithm of surface fluxes, on the other hand, was found to be a better parameter in correlating with the longitude. With regard to time trends, the exponential increases in concentrations of these BFRs, particularly DBDPE and BTBPE, in recent years are particularly disturbing. The sediment concentration of DBDPE doubles every 3-5 years in Lake Michigan, and approximately every 7 years in Lake Ontario. The corresponding doubling times for BTBPE are about 5 and 7 years in Lakes Ontario and Michigan, respectively, although declines or leveling off were observed in the top sediment layers in Lake Ontario. In contrast to PCBs, PBDEs, and most dechloranes, the correlations between the surface concentration of emerging BFRs and the latitude or longitude of the sampling sites were not strengthened by normalization of the concentration based on the organic matter content of the sediment.

Long-Range Transported Atmospheric Pollutants in Snowpacks Accumulated at Different Altitudes in the Tatra Mountains (Slovakia)

Persistent organic pollutants (POPs), including polychlorobiphenyls (PCB), endosulfans, hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polybromodiphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs), were analyzed in snowpack samples collected along an altitudinal gradient (1683-2634 meters above sea level) in the High Tatra Mountains (Slovakia). All analyzed compounds were found at all altitudes, pointing to their global distribution. The presence of PBDEs, particularly BDE 209, in the snowpack samples is especially relevant, as it reflects the air transport capacity of this low volatile, very hydrophobic pollutant to remote mountain regions. The most abundant compounds at all altitudes were PAHs, with mean values ranging from 90 to 300 ngL(-1), 1 order of magnitude higher than concentrations of other compounds. PCBs (sum of PCB 28, 52, 101, 118, 153, 138, and 180) and BDE 209 were the dominant organohalogen pollutants, with concentrations from 550 to 1600 pg L(-1) and from 670 to 2000 pgL(-1), respectively. Low brominated PBDEs, endosulfans, HCHs and HCB were consistently found in all samples at lower concentrations. The concentrations of these compounds correlated positively with altitude (i.e., negatively with temperature), which is consistent with cold-trapping effects. The regression coefficients were positive and statistically significant (p < 0.05) for all compounds except BDE 209, endosulfan sulfate, HCB and α-HCH. Contrariwise, the concentrations of BDE 209 and endosulfan sulfate exhibited a statistically significant positive correlation with total particle amount, which agrees with long-range atmospheric transport associated to aerosols according to the physical-chemical properties of these compounds. Snow specific surface area, which determines the maximum amount of each organic compound that can be sorbed by snow, proved utile for describing the distribution of the more volatile compounds, namely α-HCB and HCB, in the snowpack.

TRANSPLACENTAL TRANFER OF PERSISTENT ORGANIC POLLUTANTS IN HUMANS

Background and Aims: Transplacental transport of Organohalogen Compounds (OHs) from mother to fetus occurs during pregnancy. Fetuses are more sensitive to environmental pollutants than adults and early exposure may lead to severe repercussions for the newborn health. However, the mechanisms of OHs transference are still not well understood. Methods: The present study included 477 mother-infant pairs from a population-based cohort in Valencia, Spain, as part of the INMA (Environment and Childhood) project. We measured levels of organochlorine pesticides (OCPs) polychlorinated biphenyls (PCBs) and polybromodiphenyl ethers (PBDEs) in maternal and cord serum samples collected during 2004-2006. Results: OHs profiles showed very similar distributions in maternal and cord serum. Concentration ratios of OHs between paired samples varied between 0.40 and 0.94 on fresh weight and between 0.89 and 1.86 on lipid basis. In general, fresh weight cord concentrations of OHs were lower than in maternal serum, but when adjusted on lipid-basis cord concentrations were similar or even slightly higher than in mothers. Spearman correlations between mother-cord paired serum samples ranged from very weakly negative to strongly positive (Spearman rho= -0.01 to 0.71), we observed positive and significant correlations for concentrations of PCBs and OCPs while BDE congeners were not correlated. Conclusions: Differences in lipid content between maternal and cord serum seem to be affecting the distribution of OHs; the lipid content of fetal cord blood is low, thus its potential to accumulate OHs is also limited. When concentrations are lipid adjusted, they are about the same in the maternal-fetal system and so the placenta barrier does not prevent OH exchange. The variations observed in concentration ratios of the different OHs analyzed are likely due to dissimilar metabolism rates in mother than fetus.

ASSOCIATION BETWEEN THYROID HORMONE LEVELS AND POLIBROMODIPHENYL ETHER CONCENTRATIONS IN PREGNANT WOMEN FROM VALENCIA, SPAIN

Background and Aims: Some studies have suggested that polybromodiphenyl ethers (PBDEs) may alter thyroid function during critical periods of thyroid hormone-dependent brain development. The aim of ...

Chemometric data analysis application to Sparus aurata samples from two offshore farming plants along the Apulian (Italy) coastline

The levels of polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs), dioxin-like polychlorobiphenyls (DL-PCBs), non-dioxin-like polychlorobiphenyls (NDL-PCBs), and polybromodiphenyl ethers (PBDEs) in fish collected from two marine offshore farming plants were determined. Each sample was constituted by specimens of the same size collected at the same time in four different seasons along the farming year. The feeds given were of industrial origin and the plants were positioned in two different sites respectively exposed to different environmental characteristics. A chemometric approach was applied to interpret the subtle differences observed in fish body burdens across the three chemical groups taken into consideration. The approach consisted in a stepwise multivariate process including a hierarchical cluster analysis (CA) and a linear discriminant analysis (DA). The two main clusters determined by CA were subjected to the canonical DA, backward and forward selection procedures to select the best discriminative functions. A clear temporal and spatial discrimination was found among the samples. Across the three chemical groups, the monthly separation seemed to depend on the growth process and the main exposure was due to the feed. In addition, the two plants differed significantly from the environmental point of view and the most important discriminating group of chemicals were the NDL-PCBs. The approach resulted really effective in discriminating the subtle differences and in individuating suggestions to improve the quality of culturing conditions.

Dietary uptake of polybrominated diphenyl ethers (PBDEs), occurrence and profiles, in aquacultured turbots (Psetta maxima) from Galicia, Spain

Polybromodiphenyl ethers (PBDEs) are one of the many toxic chemicals present in the environment and in the food we eat every day, being fish one of the main sources of persistent organic pollutants in our diet; like other lipid-related contaminants, they are of concern since they can bioaccumulate and biomagnify through the trophic chain. We published a study focused on the dietary uptake of dioxins and furans (PCDD/Fs) and dioxin-like polychlorobiphenyls (dl-PCBs) in a set of samples of Spanish farmed turbot (Blanco et al., 2007). In the present paper, we extend the study to PBDEs to provide more information about the uptake and transfer from feed to fish of halogenated contaminants. PBDEs in the feeds (2.35–4.76ngg−1) were reflected in turbot fillets (0.54–2.05ngg−1): predominant congeners were tetra-BDE 47, penta-BDEs 99 and 100. It is remarkable that tetra-BDE 49, accounting for only 2% in the feed, contributed to 15% of total PBDEs in turbot fillets. Dietary net accumulation values, 30–45%, showed that tri-, tetra-, penta- and hexa-BDEs were as efficiently transferred into turbot as dl-PCBs and tetra- and penta-chlorinated PCDD/Fs. Lipid-normalized biomagnification factors relating concentration in fish and in feed, BMFs>1 were obtained, except for BDE 209. BDE 49 accumulation, 90%, was possibly contributed by metabolism of higher brominated BDEs. Implication in aquaculture management is a need for uncontaminated fish feed to offer safe products.

Forbidden of Polybromodiphenyl Ether Fire Retardant and Current Situation of its Substitutions

Environmental property of Polybromodiphenyl Ether and how it is restricted by Convention of Stockholm is introduced. Through the analysis of manufacture, application, current technique and substitution situation of Polybromodiphenyl Ether, the main problem of Polybromodiphenyl Ether Fire Retardant is pointed out, and suggestions of improvement is given in this paper.

Altitudinal distributions of BDE-209 and other polybromodiphenyl ethers in high mountain lakes

The present study shows the occurrence of 2,2′,3,3′,4,4′,5,5′,6,6′-decabromodiphenyl ether (BDE-209) in microbial biofilms of Pyrenean and Tatra high mountain lakes despite its low vapor pressure and high hydrophobicity. Aerosol air transport is therefore a feasible mechanism for BDE-209 accumulation in sites up to 2688 m above sea level. This compound and other PBDEs exhibit altitudinally-dependent distribution involving higher concentrations with increasing mountain lake elevation. However, the apparently very high enthalpies of the concentration gradients observed, including BDE-209, suggest that bacterial anaerobic debromination also plays a significant role in the resulting altitudinal distributions. This microbial mechanism explains the relative abundances of PBDEs and their within lake differences between rocky and sediment microbial biofilms, thereby showing that the altitudinal pattern observed is not purely due to water temperature control on bacterial activity but also to changes in the availability of anaerobic microenvironments which increase with increasing lake productivity at lower altitudes.

Human Milk as a Vector and an Indicator of Exposure to PCBs and PBDEs: Temporal Trend of Samples Collected in Rome

Thirty-seven polychlorobiphenyl (PCB) congeners and seven polybromodiphenylether (PBDE) congeners were measured in human milk samples collected in Rome between 2005 and 2007. The comparison of results with two previous studies performed in Rome in 1984 and in 2000-2001 indicates a 64% decrease of PCB levels, still in progress; profile differences with time were also evident as lighter congeners are less relevant now; data are in good agreement with recent European studies. PBDE contamination profiles were different in individual samples and a similar variability was observed in data from different countries, suggesting different exposure pathways and profiles.

Bioaccumulation of dioxin-like substances and selected brominated flame retardant congeners in the fat and livers of black pigs farmed within the Nebrodi Regional Park of Sicily.

An observational study was designed to assess the bioaccumulation of polychlorodibenzodioxins (PCDD) and polychlorodibenzofurans (PCDF), dioxin-like polychlorobiphenyls (DL-PCB), and 13 selected polybromodiphenylethers (PBDE) in autochthonous pigs reared in the Nebrodi Park of Sicily (Italy). Perirenal fat and liver samples were drawn from animals representative of three different outdoor farming systems and from wild pigs and then analyzed for the chemicals mentioned previously. The highest concentrations of PCDD + PCDF and DL-PCB were detected in the fat (0.45 and 0.35 pg World Health Organization toxicity equivalents [WHO-TE] per g of fat base [FB], respectively) and livers (12.7 and 3.28 pg WHO-TE per g FB) of the wild group, whereas the free-ranging group showed the lowest levels (0.05 and 0.03 pg WHO-TE per g FB in fat and 0.78 and 0.27 pg WHO-TE per g FB in livers). The sum of PBDE congeners was highest in wild pigs (0.52 ng/g FB in fat and 5.64 ng/g FB in livers) and lowest in the farmed group (0.14 ng/g FB in fat and 0.28 ng/g FB in livers). The contamination levels in fat and livers of outdoor pigs had mean concentration values lower than those levels reported for intensively indoor-farmed animals. In wild pigs, bioaccumulation was associated with their free grazing in areas characterized by bush fires. The results of this study aid to emphasize the quality of the environment as a factor to guarantee food safety in typical processed pig meat products, specifically from outdoor and extensive Nebrodi farming systems.

Effects of pre and postnatal exposure to low levels of polybromodiphenyl ethers on neurodevelopment and thyroid hormone levels at 4 years of age

There are at present very few studies of the effects of polybromodiphenyl ethers (PBDEs), used as flame retardants in consumer products, on neurodevelopment or thyroid hormone levels in humans. The present study aims to examine the association between pre and postnatal PBDE concentrations and neurodevelopment and thyroid hormone levels in children at age 4years and isolate the effects of PBDEs from those of PCBs, DDT, DDE and HCB.A prospective birth cohort in Menorca (Spain) enrolled 482 pregnant mothers between 1997 and 1998. At 4years, children were assessed for motor and cognitive function (McCarthy Scales of Children's Abilities), attention-deficit, hyperactivity and impulsivity (ADHD-DSM-IV) and social competence (California Preschool Social Competence Scale). PBDE concentrations were measured in cord blood (N=88) and in serum of 4years olds (N=244). Among all congeners analyzed only PBDE 47 was quantified in a reasonable number of samples (LOQ=0.002ng/ml). Exposure to PBDE 47 was analyzed as a dichotomous variable: concentrations above the LOQ (exposed) and concentrations below (referents).Scores for cognitive and motor functions were always lower in children pre and postnatally exposed to PBDE47 than in referents, but none of these associations was statistically significant (β coefficient (95%CI) of the total cognition score: −2.7 (−7.0, 1.6) for postnatal exposure, and −1.4 (−9.2, 6.5) for prenatal exposure). Postnatal exposure to PBDE 47 was statistically significantly related to an increased risk of symptoms on the attention deficit subscale of ADHD symptoms (RR (95%CI)=1.8 (1.0, 3.2)) but not to hyperactivity symptoms. A statistically significant higher risk of poor social competence symptoms was observed as a consequence of postnatal PBDE 47 exposure (RR (95%CI)=2.6 (1.2, 5.9)). Adjustment for other organochlorine compounds did not influence the results. Levels of thyroid hormones were not associated to PBDE exposure.This study highlights the importance of assessing the effects of PBDE exposure not just prenatally but also during the early years of life. In the light of current evidence a precautionary approach towards PBDE exposure of both mothers and children seems warranted.

Persistent organic pollutants (POPs) in fish collected from the urban tract of the river Tiber in Rome (Italy).

European eel and chub samples were analyzed to determine the levels of non-dioxin-like polychlorobiphenyls (NDL-PCBs), polychlorodibenzodioxins (PCDDs) and polychlorodibenzofurans (PCDFs), dioxin-like PCBs (DL-PCBs), and brominated polybromodiphenyl ethers (PBDEs) in order to evaluate the extent of contamination of the river Tiber along the urban tract through the city of Rome (Italy). All samples presented detectable levels of the chemicals analyzed, and exhibited species-specific differences in terms of congener composition and total concentrations. On average the European eel presented the highest values. In this species the dioxin-like compound sums (WHO-TEQs) exceeded the pertinent maximum levels (MLs). Non-ortho PCBs constituted approximately 80% of WHO-TEQ toxicological potential whereas NDL-PCB and PBDE concentrations appeared to match values determined in other polluted aquatic ecosystems where non-point contamination sources were present. The contamination patterns determined in fish tissues seemed to reflect the impact of generic contamination source(s).

Assessment of prenatal exposure to persistent organohalogen compounds from cord blood serum analysis in two Mediterranean populations (Valencia and Menorca)

Prenatal levels of organohalogen compounds (OHCs), including polybromodiphenyl ethers (PBDEs), polychlorobiphenyls (PCBs), hexachlorobenzene (HCB), hexachlorocyclohexanes and DDTs, have been investigated in two different cohorts from the Spanish Mediterranean area, Valencia and Menorca, by analysis of cord blood serum. Comparison of the observed median concentrations to other cohorts shows low PBDE levels (2.8-6.5 ng g(-1) lipid) but high values of HCB (0.68 ng ml(-1), 260 ng g(-1) lipid) and PCBs (0.65 ng ml(-1), 240 ng g(-1) lipid) in the cohort of Menorca indicating that Mediterranean areas, and not only high latitude regions, may contain population groups highly exposed to some of these pollutants. Significant differences in the concentrations of these compounds have been found between the two cohorts. Differences in maternal population such as age or body mass index cannot explain this variation. One possible cause of variability is the seven year time period elapsed between the two cohort recruitments but the strong differences observed do not allow exclusion of local diet differences. Thus, the different average PCB congener distributions between the two cohorts suggest an influence from materials containing diverse PCB mixtures. The congener mixtures found in Menorca could reflect a diet contribution from some western Mediterranean fish species. These results provide baseline information on prenatal OHC background levels in the Mediterranean area.

Induced Production of Halogenated Diphenyl Ethers from the Marine‐Derived Fungus Penicillium chrysogenum

Manipulation of the fermentation of the marine-derived fungus Penicillium chrysogenum by addition of CaBr(2) resulted in induced production of bromodiphenyl ether analogs. Two new free-radical-scavenging polybrominated diphenyl ethers, 1 and 2, and three known diphenyl ethers, 3,3'-dihydroxy-5,5'-dimethyldiphenyl ether (3), and an inseparable mixture of violacerol-I (4) and violacerol-II (5) were isolated. The structures of the two new polybromodiphenyl ethers 1 and 2 were assigned by combined spectroscopic-data analysis, including deuterium-induced isotope effect. Compounds 1-3, and a mixture of 4 and 5 exhibited radical-scavenging activities against 1,1-diphenyl-2-picrylhydrazyl with IC(50) values of 18, 15, 42, and 6 μM, respectively. With the exception of 3, the compounds were, therefore, more active than the positive control, ascorbic acid (IC(50) 20 μM).

Polybromodiphenyl ethers in mothers and their newborns from a non-occupationally exposed population (Valencia, Spain)

Polybromodiphenyl ethers (PBDEs) were analyzed in blood serum of pregnant women and in cord blood serum of their newborns from a general population cohort (n = 174; Valencia, Spain). The most abundant PBDE congeners identified were BDE 47, BDE 99, BDE 153, BDE 154 and BDE 209. Their cord blood serum concentrations were about 45% of those in maternal serum but after lipid normalization about the same concentrations were observed in both types of samples. Thus, median of total PBDEs was 9.6 ng/g lipid in cord serum (range between not detected and 140 ng/g lipid) and 9.6 ng/g lipid in maternal serum (range between not detected and 120 ng/g lipid). The distributions of these compounds were dominated by BDE 47 in both cases. In cord blood serum the decreasing order of abundance was BDE 47 > BDE 99 > BDE 209 > BDE 153 > BDE 154. The congener composition in maternal serum followed a similar trend: BDE 47 > BDE 153 > BDE 154 > BDE 209 > BDE 99. The congener concentrations exhibited a higher degree of correlation in cord blood than in maternal serum. Use of the maternal determinants for categorization of the observed maternal and fetal PBDE concentrations only showed significant associations for the levels in umbilical cord. Neonates from rural areas exhibited statistically significantly lower concentrations than those from urban, semi-urban or metropolitan sites. Maternal serum also showed this difference but the higher dispersion of the concentrations in maternal serum did not afford its recognition with statistical significance. The lower qualitative and quantitative variability in the PBDE concentrations of cord blood serum than maternal serum suggest that the latter is reflecting PBDE contributions from a wider diversity of sources than the former whereas cord blood sera seem to represent the long term standing stock of these compounds accumulated in the maternal tissues.

Persistent organic pollutants and enzyme activities in European eel (Anguilla anguilla) from Orbetello lagoon

The aim of the present study was to obtain insights into the environmental quality of Orbetello lagoon using the European eel ( Anguilla anguilla ) as bioindicator organism. Levels of POPs, including seven polychlorobiphenyls (PCBs) (known as markers of Aroclor 1260), three coplanar PCBs, ΣDDT ( op -DDD, pp’ -DDD, op -DDT, pp’ -DDT, op’ -DDE, pp’ -DDE), hexachlorobenzene (HCB), hexachlorocyclohexane (HCH: α-HCH, β-HCH, γ-HCH, δ-HCH), polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzo-p-furans (PCDFs) and polybromodiphenylethers (PBDEs), were investigated in eel muscle to study bioaccumulation of toxic compounds. EROD MROD and UDPGT activities were measured in liver microsomal fraction to investigate eel detoxifying/metabolic capacity. Ovaries were analyzed by light microscopy to evaluate potential risk for eel reproduction. Muscle concentrations of PCBs, DDTs, pp’ -DDE, HCB and HCHs were in the ng/g lipid weight (l.w.) range while coplanar PCBs were in the pg/g wet weight range. PCDD/Fs were below the detection limit. Toxic equivalents (TEQs) calculated for mono- and non- ortho PCBs were below the risk thresholds established by the European Union. EROD, MROD and UDPGT activities suggested low exposure to chemical inducers in line with the low concentrations of contaminants observed in muscle. Principal components analysis (PCA) showed a potential role of DDTs, especially pp’ -DDE, in inducing EROD, MROD and UDPGT activities. All specimens analysed were females; oocytes in advanced stages of development showed normal morphology, whereas those in early stages of development showed histological anomalies.

Integrated analysis of halogenated organic pollutants in sub-millilitre volumes of venous and umbilical cord blood sera

A rapid, robust and economical method for the analysis of persistent halogenated organic compounds in small volumes of human serum and umbilical cord blood is described. The pollutants studied cover a broad range of molecules of contemporary epidemiological and legislative concern, including polychlorobiphenyls (PCBs), polychlorobenzenes (CBs), hexachlorocyclohexanes (HCHs), DDTs, polychlorostyrenes (PCSs) and polybromodiphenyl ethers (PBDEs). Extraction and clean-up with n-hexane and concentrated sulphuric acid was followed with analysis by gas chromatography coupled to electron capture (GC-ECD) and GC coupled to negative ion chemical ionisation mass spectrometry (GC-NICI-MS). The advantages of this method rest in the broad range of analytes and its simplicity and robustness, while the use of concentrated sulphuric acid extraction/clean-up destroys viruses that may be present in the samples. Small volumes of reference serum between 50 and 1000 microL were extracted and the limits of detection/quantification and repeatability were determined. Recoveries of spiked compounds for the extraction of small volumes (> or = 300 microL) of the spiked reference serum were between 90% and 120%. The coefficients of variation of repeatability ranged from 0.1-14%, depending on the compound. Samples of 4-year-old serum and umbilical cord blood (n = 73 and 40, respectively) from a population inhabiting a village near a chloro-alkali plant were screened for the above-mentioned halogenated pollutants using this method and the results are briefly described.

A convenient method for the reductive degradation of mono-, di-, and tribromodiphenyl ethers, tetrabromo- and tetrachlorobisphenol A with Raney Ni-Al alloy

Raney Ni-Al alloy in a dilute aqueous alkaline solution of NaOH, KOH, CsOH, LiOH, or Ca(OH)2, or of alkali metal carbonates such as Na2CO3, K2CO3 and Cs2CO3, becomes a very powerful reducing agent and dehalogenates mono-, di and tribromodiphenyl ethers (BDPEs), tetrabromobisphenol A (TBBPA) and tetrachlorobisphenol A (TCBPA) effectively. Polybromodiphenyl ethers are reduced to give diphenyl ether as sole product. TBPPA and TCPPA are debrominated to bisphenol A and other dehalogenated compounds. The C-C bond of bisphenol A is broken easily under the reaction conditions. An almost quantitative removal of halogen from BDPEs, TBBPA and TCPPA can be realized in aqueous media under mild reaction conditions without the use of organic solvents. The reductive dehalogenation of TBBPA and TCBPA with a Raney Ni-Al alloy under ultrasonication is also described.