Polychlorinated biphenyls in the environment

Impact of Anaerobic and Aerobic Processes on PolyChloroBiphenyl Removal in Contaminated Sewage Sludge

Aerobic and anaerobic biodegradation of six priority PCBs was investigated in continuous stirred tank reactors fed with naturally contaminated sewage sludge. Anaerobic and aerobic abiotic losses were higher for the lightly chlorinated PCBs but remained for all PCBs below 20%. Under strict methanogenic conditions, PCB removals were about 40% whatever PCB molecular weight or their degree of chlorination. However, considering abiotic losses, the heaviest PCBs were more efficiently anaerobically biodegraded probably because of higher dechlorination rates. The aerating sludge process enhanced removal of the lightest chlorinated PCBs from 40% up to 100%, while removal rates of the heaviest PCBs remained around 40%. Although the mesophilic aerobic process exhibits better removal efficiencies because of operating conditions, the results suggest that PCB biodegradation was strongly limited by their bioavailability in naturally contaminated sludge, under both redox conditions. Indeed, since PCB removal was closely linked to the solid reduction rates, PCB bioavailability was likely the limiting factor for biodegradation. As a consequence, the raw PCB concentrations (in mg kg(-1) (dry weight)) which are concerned by legislative procedures did not decrease sufficiently in both processes to reach a limit value fulfilling the current French/European regulation about PCB contents in sewage sludge before spreading on agricultural land.

Mechanochemical Degradation of Aromatic Sulfonic Acids

Sulfonic acids and sulfonates are widely used as surfactants in various industrial processes. Although partial biodegradation occurs, their release in the environment has determined a widespread pollution problem due to their remarkable tendency towards accumulation. For this reason, various methodologies to effectively degrade sulfonic acids and sulfonates in real matrices are currently under investigation. In this study, we focused our attention on the mechanochemical degradation of the 1,5-naphthalene disulfonic acid using strongly reducing agents such as pure Mg and Ca metals. The mechanochemical processing induced either a gradual degradation of the organic compound or a combustion-like reaction depending upon the experimental conditions. A partial degradation of the sulfonic acid was observed as a result of gradual reactions. An almost complete removal of the pollutant was instead observed after combustion-like reactions.

Determining PAHs and PCBs in aqueous samples: finding and evaluating sources of error

This work describes the problems that occur during routine multi-step determinations of polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), which can be present at trace levels in water, and identifies sources of analyte losses at particular steps during the analytical procedure. PAH and PCB adsorption onto the walls of the container ranged from 0 to 70%. PAH and PCB recoveries of >70% were achieved during the LLE and SPE extraction steps. During the process of enriching the dichloromethane extract with PAHs and PCBs, based on the gentle evaporation of solvent, losses were <24% and <19%, respectively. Model experiments show that neither isolation of PAHs and PCBs (performed using either LLE or SPE) nor extract enrichment reduce the reliability of PAH and PCB determination. The steps that lead to the greatest loss of analyte are the ones that involve sampling, transport and storage of the water samples.

Enantioselective semipreparative HPLC separation of PCB metabolites and their absolute structure elucidation using electronic and vibrational circular dichroism

Polychlorinated biphenyls (PCBs) remain one of the most important groups of environmental contaminants. The fate (transformation) as well as the toxicological implications of the different metabolism steps are subject to considerable debate. The aim of this study is to start a comprehensive investigation of atropisomeric PCB metabolites, i.e., hydroxy, methoxy, methylthionyl, and methylsulfonyl PCBs in different biota. For this purpose, enantioselective semipreparative liquid chromatography is used to obtain pure enantiomers of PCB metabolites. Electronic circular dichroism (UV-CD) and vibrational circular dichroism (VCD) in combination with computational techniques were applied to determine their absolute structures. Approximately 18-25 mg of each enantiomer of the following metabolites were obtained using semipreparative HPLC on beta-cyclodextrin-based columns: 4-MeO-CB149, 4-MeS-CB149, 4-MeSO2-CB149, 3-MeS-CB149, and 3-MeSO2-CB149. The enantiomeric purity of the separated enantiomers was in the range of 95.0-99.9%. Rotational angles and absolute configurations were also determined. This study establishes a sound method for future preparation and absolute structure determination of compounds belonging to the same class.

Investigation of saponification for determination of polychlorinated biphenyls in marine sediments

The effects of saponification conditions (temperature and water content of saponifying solution) on the determination of chlorinated biphenyls (CBs) in marine sediments were investigated. Although highly chlorinated biphenyls (nona- to deca-CBs) decomposed during high-temperature saponification, the degree of degradation was reduced by adding water to the ethanolic potassium hydroxide saponifying solution. Room-temperature saponification yielded quantitative recovery of highly chlorinated biphenyl surrogates but low extraction efficiencies of lightly chlorinated biphenyls (mono- to di-CBs). The same samples were analyzed by other extraction techniques, for example, pressurized liquid extraction, and analytical results were compared. The mono- and di-CB concentrations were correlated with the extraction temperatures of various extraction techniques. In particular, the concentrations of some CB congeners (CB11, CB14) were higher with saponification. The low degree of degradation of highly chlorinated biphenyls and the high recovery of lightly chlorinated biphenyls were compatible when room-temperature and high-temperature saponification were combined. Except for the anomalies of CB11 and CB14, the combined method gave satisfactory results for analysis of PCBs.

A simple and fast micromethod for the analysis of polychlorinated biphenyls in air by sorbent enrichment and ultrasound-assisted solvent extraction

A combination of sorbent enrichment and ultrasound-assisted solvent extraction has been used to determine polychlorinated biphenyls in air. Analytes were sampled by pumping a known volume of air through a porous polymer (Tenax TA). The enriched adsorbent was transferred into a glass vial, and ultrasound-assisted extraction of the analytes was then performed in n-hexane. Quantification was carried out by using gas chromatography coupled to tandem mass spectrometry. Breakthrough volume of the sampling step was studied, indicating that 10 m3 of air could be processed without losses of the most volatile compounds. Good recoveries (75-96%) were obtained, and limits of detection at the sub ng m(-3) were achieved for all the analytes. The proposed method is very simple and fast, avoiding the use of large solvent volumes and time-consuming preconcentration steps.

Improved separation of the 209 polychlorinated biphenyl congeners using comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry

The separation of the 209 polychlorinated biphenyl (PCB) congeners has been studied using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC x GC-TOFMS). Four column combinations based on thermally stable phases, DB-1/HT-8, DB-XLB/HT-8, DB-XLB/BPX-50, and HT-8/BPX-50, have been investigated. The HT-8/BPX-50 set produced the best separation. The distribution of the 100 to 150 ms wide peaks was highly structured in the chromatographic space and based on the degree of ortho-substitution within each separated homologue series. A total of 192 congeners were resolved in 146 min (1.3 analyte per min) using this column set. Eight coelutions involved 17 congeners. Among them, seven congeners were present in Aroclors at levels >1.0 wt.% (CBs 33, 47, 48, 95, 97, 163, 187). Except for CBs 47 and 48, none of the major constituents of commercial mixtures were coeluting. CB 138 was well separated from CBs 163 and 164 in the second dimension. For all column sets, CBs 20, 33, and 109 always coeluted with other PCBs. The 12 toxic dioxin-like congeners (CBs 77, 81, 105, 114, 118, 123, 126, 156, 157, 167, 169, 189), and the seven European Union marker PCBs (CBs 28, 52, 101, 118, 138, 153, 180) were separated from any interfering congeners. This was not the case for the other investigated column sets.

Solid-phase extraction clean-up of soil and sediment extracts for the determination of various types of pollutants in a single run

A new sample clean-up procedure based on solid-phase extraction (SPE) sorbents was proposed for the determination of pesticides, polycyclic aromatic hydrocarbons and polychlorinated biphenyls in soils and sediments. The main purpose of the research was to find a combination of sorbents for the SPE method that would permit the determination of many types of analytes (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, N-, P- and Cl-containing pesticides) in a single run. Elution profiles for both the analytes and the interfering components were determined for several types of SPE sorbents (alumina, silica and surface-modified silica) and combinations of them. The efficiency of the clean-up method developed was evaluated using real soil samples.

Developments in the use of chromatographic techniques in marine laboratories for the determination of halogenated contaminants and polycyclic aromatic hydrocarbons

Chromatography has been an important tool in marine laboratories. Since the 1960s, marine laboratories have been involved in the analysis of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), and brominated flame retardants (BFRs). Column chromatography and liquid chromatography (LC) techniques have been used, mainly in the clean-up phase, while gas chromatography (GC) has been used extensively in the final determination of these contaminants. Developments have been observed from the use of packed GC columns, via capillary columns to the use of heart-cut multi-dimensional GC and comprehensive multi-dimensional GC. The progress made in interlaboratory studies and the availability of certified reference materials are discussed.

PCBs, PCNs, PCDD/Fs, PAHs and Cl-PAHs in air and water particulate samples--patterns and variations

Methodology for the determination of biologically active polychlorinated biphenyls (PCBs), non-ortho PCBs, polychlorinated naphthalenes (PCNs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs) was used to investigate concentrations and patterns of certain chlorinated PAH (Cl-PAH) in source related samples using synthetic reference mixtures. Thus, in addition to the above mentioned compounds, mono-heptachlorosubstituted fluorenes, phenanthrenes/anthracenes and pyrenes/fluoranthenes (Cl-PAHs) were measured in vapour and particulate air samples from urban road tunnels, samples of settling particulate matter (SPM), and in bottom sediment samples from two point source locations (pulp and paper, and Mg-plant/Fe-Mn-smelter/chlor-alkali) and in the Baltic Sea. Concentrations in air samples followed: PAHs>PCBs>PCNs>non-ortho PCBs or Cl-PAHs>PCDD/Fs. SPM samples collected at increasing distance to the urban area of Stockholm showed: PAHs>PCBs>PCNs>PCDD/Fs>non-ortho PCBs or Cl-PAHs. For all compound groups there was a tenfold (Cl-PAHs fivefold) concentration decrease in SPM samples from highest levels in the urban water area to lowest levels at a distance of 26 km from city centre. PCB profiles of SPM showed similarities with combined profiles of Aroclor 1242 and 1254. PCN profiles of SPM showed similarities with combined profiles of Halowax 1099 and 1014. A correlation with concentration of all tested Cl-PAH and their corresponding parent PAH was found only for Cl-fluorene.

Polychlorinated biphenyls as initiators in liver carcinogenesis: resistant hepatocyte model

A modified Solt-Farber protocol was established to investigate the potential initiating activity of lower chlorinated polychlorinated biphenyl (PCB) congeners in rat liver. Two different studies were conducted in male Fisher 344 rats. PCBs investigated were PCB3, PCB12, PCB38, and PCB77 in study 1 and PCB15, PCB52, PCB77, and the combination of PCB52 and PCB77 in study 2. Rats were subjected to partial hepatectomy followed by a single dose of the suspected initiating agent, diethylnitrosamine, or vehicle. Two weeks later all groups received selection treatment consisting of three daily doses of 2-acetylaminofluorene (2-AAF) and then a single dose of carbon tetrachloride, followed by three additional daily treatments of 2-AAF via gavage. Rats were killed 2 weeks after the last treatment of 2-AAF, and the number and volume of gamma-glutamyltranspeptidase (GGT)-positive foci were determined. Among the PCBs tested, PCB3, PCB15, PCB52, and PCB77 significantly increased the number of GGT-positive foci per cm(3) of liver and per liver. Only PCB3 and PCB15 increased the volume fraction of GGT-positive foci. Histopathologic analysis of hematoxylin- and eosin-stained liver sections showed that rats with significantly increased GGT-positive foci also had extensive cellular alteration. This effect was not seen in nonselection groups. We conclude that, under the conditions and time courses of these experiments, several PCBs have initiating activity in male Fischer 344 rats.

Solid state dehalogenation of PCBs in contaminated soil using NaBH4

In this work we present the results of an experimental study on the abatement of polychlorinated biphenyl (PCBs) in contaminated soil using a high energy milling technique, that promotes a reaction only by impact between milling bodies. A sample of soil from a controlled landfill was treated with powdered NaBH(4) using two different hydride/soil ratios (5 and 2.5% w/w). The efficiency of the dehalogenation/hydrogenation reaction was studied as a function of the milling time (3.5 up to 30 h). After each run, the total PCBs content and the production of inorganic chloride were measured. The complete abatement was obtained with a starting PCBs concentration of about 2600 mg/kg. The residual PCBs concentration resulted to be <0.2 mg/kg. The final products of the treatment were biphenyl and NaCl. Other toxic or hazardous organic by-products were not generated. Boron was found as boric acid.

Chiral separation of polychlorinated biphenyls using a combination of hydroxypropyl-gamma-cyclodextrin and a polymeric chiral surfactant

Chiral separation of moderately to highly hydrophobic polychlorinated biphenyls (PCBs) using a conventional chiral micelle or a polymeric chiral surfactant, as the single chiral selector is very difficult since the hydrophobic interactions between the chiral PCB and the monomeric or polymeric surfactant is very strong. Combined use of a polymeric chiral surfactant, polysodium N-undecanoyl-D-valinate (poly-D-SUV) with hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD) was successful in cyclodextrin modified electrokinetic chromatography (CD-EKC) enantioseparation of PCB congeners. Addition of HP-gamma-CD to the background electrolyte containing poly-D-SUV functioned to improved chiral resolution for the PCBs and reduce the analysis time for these congeners. In addition, concentration of methanol, concentration of 2-(N-cyclohexylamino) ethanesulfonic acid (CHES) buffer and separation voltage was also varied to optimize multicomponent separation of five chiral PCBs. Simultaneous separation and enantioseparation of all five PCBs was possible in less than 50 min under optimized conditions that requires a 5 mM CHES solution buffered at about pH 10 with 1.5% w/v (ca. 60 mM) poly-D-SUV and 16 mM HP-gamma-CD. In addition, 1 M urea and 20% v/v methanol should be added as organic modifier and the capillary temperature maintained at 45 degrees C. As expected the polymeric surfactant showed improved chiral resolution of PCBs over conventional micelles of SUV. Under optimized conditions, when CD-EKC of chiral PCBs using poly-D-SUV was compared to sodium dodecyl sulfate (SDS), better resolution, higher efficiency and shorter analysis time was achieved with poly-D-SUV.

Sulfhydryl binding and topoisomerase inhibition by PCB metabolites

Polychlorinated biphenyls (PCBs) are highly persistent contaminants in our environment. Their persistence is due to a general resistance to metabolic attack. Lower halogenated PCBs, however, are metabolized to mono- and dihydroxy compounds, and the latter may be further oxidized to quinones with the formation of reactive oxygen species (ROS). We have shown that PCB metabolism generates ROS in vitro and in cells in culture and this leads to oxidative DNA damage, like DNA strand breaks and 8-oxo-dG formation. In the present study, we have evaluated the reactivity of PCB metabolites with other nucleophiles, like glutathione (GSH), by assessing (1) quantitative GSH binding in vitro, (2) GSH and thiol (sulfhydryl) depletion in HL-60 cells, (3) the associated cytotoxicity, and (4) the inhibition of topoisomerase II activity in vitro. PCB quinones were found to bind GSH in vitro at a ratio of 1:1.5 and to deplete GSH in HL-60 cells as measured by both spectrophotometric and spectrofluorometric methods. By flow cytometry analysis, we confirmed that there was intracellular GSH depletion in HL-60 cells by PCB quinones and this is associated with cytotoxicity. On the other hand, the PCB hydroquinone metabolites did not bind GSH or other thiols within 1 h of exposure. However, by spectral analyses we found that the PCB hydroquinones could be oxidized enzymatically to the quinones, which could then bind GSH. The resulting hydroquinone-glutathione addition product(s) could undergo a second and third cycle of oxidation and GSH addition with the formation of di- and tri-GSH-PCB adducts. The effect of the PCB metabolites was also tested on a sulfhydryl-containing enzyme, topoisomerase II. PCB quinones inhibited topoisomerase II activity while the PCB hydroquinone metabolites did not. Hence, the oxidation of PCB hydroquinone metabolites to quinones in cells followed by the binding of quinones to GSH and to protein sulfhydryl groups and the resulting oxidative stress may be important aspects of the toxicity of these compounds.

Halogenated organic contaminants in sediments of the Havel and Spree rivers (Germany). Part 5 of organic compounds as contaminants of the Elbe river and its tributaries

To give a detailed and comprehensive view on the state of pollution of the Havel and Spree rivers nontarget screening as well as quantitative (target) analyses were applied to anoxic sedimentsamples. Based on nontarget GC/MS analysis a significant contribution to the anthropogenic contamination could be attributed to halogenated compounds. Three groups of contaminants corresponding either to diffuse or local contamination could be distinguished. Several commonly observable compounds including pentachloroanisol, polychlorinated biphenyles, 2,4-dichlorobenzoic acid, and chlorinated benzenes were detected with a distribution reflecting the contribution of nonpoint source emissions. A second group of chlorinated as well as brominated compounds was attributed to a strong point source emission at the Teltow Canal. At the sampling locations influenced by this point source the amount of mono- and dibrominated naphthalenes, chlorinated naphthalenes, and hexachlorocyclohexanes as well as DDT- and methoxychlor-related compounds increased significantly as compared to the background concentrations. A third group of halogen compounds emitted at this site consisted of the pesticides bromopropylate, methoxychlor, and chlorfensone as well as specific brominated aromatics including 2,4,6-tribromoaniline, 4,4'-dibromobenzophenone, and brominated benzenes. In addition, tetrabromochlorotoluenes, tribromodichlorotoluenes, dibromotrichlorotoluenes, and 2,2-bis(4-bromophenyl)acetic acid isopropyl ester were identified and are reported for the first time as environmental contaminants. The amounts of brominated compounds detected in Teltow Canal sediments occurred at a similar concentration level as their chlorinated analogues. Therefore, investigations on the occurrence of such a broad spectrum of brominated compounds as established in this work are presumably required more frequently to assess the environmental impact of this type of emissions.

The organochlorine contamination history of the Mersey estuary, UK, revealed by analysis of sediment cores from salt marshes

Sediment profiles in the Banks, Ince and Widnes Warth salt marshes in Northwest England contain a mappable record of historic pollution. For persistent organochlorine compounds this stretches back over 90 years. The PCB and HCH profiles can be successfully rationalised by dating methods, and they can be related to the dates of initial production and subsequent withdrawal from use of these chemicals as a result of restrictive environmental legislation. HCB has a more complex pollution profile as it has been manufactured in Northwest England, both deliberately as a pesticide and accidentally as a by-product of several chlorination processes, dating back to the start of the 20th century. The concentrations of degradation products of DDT are relatively constant through the sediment profile and are dominated by op'- and pp'-DDD with only minor contributions from the most toxic species, pp'-DDT. The quantities of these compounds resident in the reservoir of pollutants under these marshes have been calculated, and have fallen progressively in the last 30-50 years.

Polychlorinated biphenyl-induced effects on metabolic enzymes, AP-1 binding, vitamin E, and oxidative stress in the rat liver

Environmental pollutants, such as polychlorinated biphenyls (PCBs), may induce drug metabolism and may be substrates for the induced metabolic enzymes. Both processes may lead to oxidative stress. The goal of this study was to determine the influence of polychlorinated biphenyls, selected as inducers and substrates of drug metabolism, on oxidative events within the liver over a 3-week time course. Male and female Sprague-Dawley rats received two ip injections per week of 4-chlorobiphenyl, 2,4,4'-trichlorobiphenyl, 3,4,5-trichlorobiphenyl, 3,3',4,4'-tetrachlorobiphenyl (PCB 77), 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153), or both PCB 77 and 153 (100 micromol/kg/injection) and were euthanized at the end of 1, 2, or 3 weeks. Hepatic cytochrome P450 1A1 (EROD) activity, DT-diaphorase activity, AP-1 DNA-binding activity, conjugated dienes, and alpha-tocopherol (vitamin E) as well as alpha-tocopheryl quinone (oxidized vitamin E) were determined. While the lower chlorinated biphenyls (at these doses and times) showed little or no effect on these oxidative stress parameters, both CYP 1A1 and DT-diaphorase activities were significantly increased in both male and female rats receiving PCB 77, a ligand for the aryl hydrocarbon receptor. In addition, the DNA-binding activity of the transcription factor AP-1 was increased in rats treated with PCB 77 or PCB 153. Within the lipid fraction there was no significant increase observed in conjugated diene concentrations, but there was a significant increase in alpha-tocopheryl quinone upon treatment with all PCBs tested. These data indicate that alpha-tocopheryl quinone may be a sensitive marker for PCB exposure and is possibly increased by a wide range of PCBs.

Tissue distribution of polychlorinated naphthalenes (PCNs) and non-ortho chlorinated biphenyls (non-ortho CBs) in harbour porpoises (Phocoena phocoena) from Swedish waters

Polychlorinated naphthalenes (PCNs) and non-ortho chlorinated biphenyls (non-ortho CBs) were analysed in blubber, nuchal fat, liver, muscle, kidney and brain of three male harbour porpoises (Phocoena phocoena) from the west coast of Sweden. To estimate spatial variation, PCNs and non-ortho CBs were analysed in six blubber samples collected at different anatomical sites of each animal. Highest wet weight concentrations of sigma PCNs were detected in the lipid rich tissues (blubber and nuchal fat) and liver (520-730 and 520 pg/g, respectively) and lowest in brain (22 pg/g). TetraCNs were most abundant in muscle, kidney and brain, while the hexaCNs were most abundant in the lipid rich tissues and liver. The highest lipid weight concentration recorded (11 ng/g) was for the hexaCN congeners no. 66/67 in liver. These coeluting hexaCN congeners accounted for 80-100% of total hexaCNs in all tissues examined. Concentrations of sigma non-ortho CBs were highest in lipid rich tissues (220-280 pg/g wet weight). Non-ortho CB no. 77 and 169 constituted between 62-86% and 4.9-9.3%, respectively, of total sigma non-ortho CBs. No major variation of sigma non-ortho CB concentrations was found between the six different blubber sites but higher sigma PCN concentrations (wet weight) were found dorsally at the peduncle. Toxic equivalent concentrations (TEQs) showed that non-ortho CB no. 126 was the main contributor to total TEQs in all tissues, except liver in which hexaCN congener nos. 66/67 contributed to about 50% of total TEQs.

Recent developments in the high-resolution gas chromatography of polychlorinated biphenyls

The capillary gas chromatography of polychlorinated biphenyls (PCBs) is reviewed. Focus is on the most recent developments in the separation and detection of PCBs rather than sample preparation methods. Included are a comprehensive look at stationary phases that have been used to separate PCBs and the relatively new work on chiral separations of PCBs. Mass spectrometry and atomic emission are presented as selective detection techniques. Suggestions for additional research are proposed where appropriate.

PCB congener patterns in rats consuming diets containing Great Lakes salmon: analysis of fish, diets, and adipose tissue

As part of a multidisciplinary toxicological investigation into Great Lakes contaminants, chinook salmon were collected from Lake Huron (LH) and Lake Ontario (LO) and incorporated (as lyophilized fillets) into standard rat diets as 20 or 100% of the protein complement (5 or 20%, w/w diet-LH5, LH20, LO5, and LO20 diets). Final PCB concentrations in the experiment ranged from 3.15 ng/g in the control diet to 1080 ng/g in the high-dose (20%) LO diet, with maximal estimated daily consumption by the rats of 82microg PCBs/kg body wt in the LO20 dietary group. Seventeen PCB congeners, PCB 85, 99, 101, 105, 110, 118, 128, 129, 132, 138, 149, 153, 170, 177, 180, 187, and 199, occurred at >/=3.0% of the total PCBs in the fish with no major site differences. Cumulatively, these 17 congeners accounted for up to 75% of the total PCBs in the fish compared to 44 and 54% in two commercial Aroclors, 1254 and 1260, respectively. PCB 77 was the major "dioxin-like" congener in the fish, followed by PCB 126 and then PCB 169. All major dietary congeners bioaccumulated in the adipose tissue of the rats with the exception of PCB congeners 101, 110, 132, and 149. The group of 17 major congeners accounted for up to 71% of the total PCBs in adipose tissue samples collected from the rats following up to 19 weeks of diet ingestion. Of the coplanar PCB congeners, PCB 77 appeared to bioaccumulate to a lesser extent compared to PCBs 126 and 169. When comparing PCBs in the rat adipose tissue to PCB congeners in Canadian breast milk, PCBs 44, 49, 74, and 137 tended to occur in higher amounts in the human samples (contributing together 18.4 vs. 1.4% of the total PCB concentration), whereas PCB 129 occurred at higher levels in the rats (3.4 vs. 0.3% of the total PCB concentration, respectively). Although adipose tissue from the rats fed diets containing Great Lakes salmon had up to two orders of magnitude higher concentrations of PCBs compared to average human values, with the exception of some lower chlorinated congeners, similar major congeners tended to be present in both the rats in the present study and humans.

Report of the WHO working group on the assessment of health risks for human infants from exposure to PCDDs, PCDFs and PCBs

On Nov. 20-22, 1995, a World Health Organization working group consisting of 12 scientific representatives from 6 different countries met to reassess the health risks to infants associated with perinatal exposure to polyhalogenated aromatic hydrocarbons (PHAHs). Following a review of previous WHO/EURO consultations, as part of their comprehensive programme on PCDDs, PCDFs and PCBs, current exposure information and recent experimental and epidemiologic data were discussed. Exposure assessments within the past decade have revealed that in the case of breast milk samples concentrations of PCDDs/DFs and PCBs have shown a continual decline, in certain countries by up to 50%. New experimental data has revealed that a variety of structural, functional and behaviourial alterations can be induced in rodent species following exposure to PHAHs while a Dutch collaborative PCB/dioxin study has illustrated subtle clinical, endocrine and mental/psychomotor development effects can occur in breast fed infants. The provisional conclusions of the working group were: 1) current evidence does not warrant altering the previous WHO recommendation for promotion/support of breast feeding and 2) based on new clinical data which supports the biological plausibility of certain observed experimental observations, continued and enhanced effort should be directed towards identifying and controlling sources of environmental input for these contaminants.

Levels of polychlorinated biphenyls in some waste motor and transformer oils from Poland

Waste motor and transformer oils are considered as a main source of polychlorinated biphenyls (PCBs) emission into the environment. The levels of total PCB in twenty six randomly selected samples of waste motor and transformer oils from different regions of Poland were studied. The clean-up of the extracts on two solid phase extraction columns system and determination of PCBs by capillary gas chromatography with electron capture detection were performed. The determined content of PCBs in motor oils was by one order of magnitude higher than in transformer oils, but in the both types of analysed samples, except one sample, did not exceed 50 micrograms/g.

Polychlorinated biphenyls affect the activities of gluconeogenic and lipogenic enzymes in rat liver: is there an interference with regulatory hormone actions?

1. The effects of dietary polychlorinated biphenyls (PCBs) (30-2000 ppm) on activities of gluconeogenic (phosphoenolpyruvate carboxykinase-PEPCK, and fructose 1,6-bisphosphatase-FdPase) and lipogenic enzymes (fatty acid synthase-FAS, ATP citrate lyase-ACL, malic enzyme-ME, glucose 6-phosphate dehydrogenase-G6PDH, and 6-phosphogluconate dehydrogenase-PGDH) were studied in livers of the female Sprague-Dawley and Wistar rat. 2. PCB amounts accumulating in the liver reflected the extent of dietary exposure. The Wistar strain was more sensitive to PCBs than the Sprague-Dawley strain. Of the Clophentype PCBs those containing 60 and 64% chlorine displayed the most pronounced effects. 3. Activities of gluconeogenic enzymes (PEPCK and FdPase) were dose-dependently decreased by PCBs, PEPCK being considerably more sensitive. This decrease was also found under conditions where the activity of PEPCK was induced (administration of adrenalin, glucagon or cAMP, feeding high protein diets, starvation). 4. Activities of lipogenic enzymes were induced by PCBs. The increase was much greater with ME, G6PDH and PGDH (up to 10-fold) than with FAS and ACL (approximately 2-fold). PCB effects were dose-dependent, but transient. 5. In cultured hepatocytes basal activities of lipogenic enzymes were induced by PCBs in the absence of hormones. With saturating levels of insulin or triiodothyronine, enzyme activities were also induced, but addition of PCBs resulted in an additive effect. 6. These results suggest that in the female rat PCBs can mimic the actions of certain hormones by affecting either hormone levels, hormone receptor systems or regulatory systems.

Determination of polychlorinated biphenyls and chlorinated pesticides in human body fluids and tissues

A fast and reliable method for the determination of polychlorinated biphenyls (PCBs) and chlorinated pesticides in human body fluids and tissues is presented. Sample clean-up and selective enrichment of analytes are carried out by liquid column chromatography without a prior solvent extraction step. Analytes are determined either by high-resolution capillary gas chromatography with mass spectrometric detection, or by dual-column GC followed by electron-capture detection. A procedure is described for the simultaneous determination of environmental levels of the PCB congeners 28, 52, 101, 138, 153 and 180 in human cord serum. The method allows the simultaneous determination of chlorinated pesticides such as aldrin, DDT, DDE, BHC and HCB and is also applicable to other biological matrices, such as bone marrow or tissues.

Current developments in the analysis of water pollution by polychlorinated biphenyls

A review and discussion of the analytical developments of the last 10 years in the determination of polychlorinated biphenyls (PCBs) in water are presented, including sample treatment, clean-up, identification and determination. Some of the most significant advances have occurred in the area of sample preparation, such as the increased adoption of solid-phase extraction and on-line techniques and the chromatographic separation of PCB congeners, principally by mass spectrometry. Special attention is focused on applications to real samples.

Developmental neurotoxicity of PCBs in humans: what do we know and where do we go from here?

The potential neurotoxicity of PCBs was first recognized in 1968 when a number of Japanese people became ill after ingesting rice oil that was contaminated with PCBs during the manufacturing process (Yusho). Later a similar exposure occurred in Taiwan (YuCheng). Children born to Taiwanese mothers who consumed PCB-contaminated rice oil were followed and a number of developmental abnormalities, including lower body weight and height, higher activity levels, greater incidence of behavior problems, and lower IQ scores, were observed. However, interpretation of these findings is complicated by the fact that there did not appear to be any relationship between available indices of exposure and severity of effects, and by the fact that the PCBs to which the Taiwanese were exposed contained unusually high concentrations of dibenzofurans, which are many times more toxic than PCBs, and may have been responsible for some or all of the observed effects. Since the Yusho and YuCheng episodes, several studies have been initiated to study the neurobehavioral effects of exposure to the lower levels of PCBs present in the environment. The two studies published to date have yielded conflicting results. Jacobson, Jacobson, and colleagues reported that in utero PCB exposure was associated with decreased birth weight and head circumference, shorter gestation, and several adverse outcomes on the Brazelton Neonatal Assessment Battery. Later they reported that the body weight deficits associated with prenatal PCB exposure were still present at 5 months and 4 years of age. Deficits in memory function were observed at 7 months and 4 years. Rogan, Gladen, and colleagues did not find any evidence of decreased birth weight or head circumference. Nor did they find any evidence of deficits in memory function. However, they did observe some similar effects on the Brazelton Neonatal Assessment Battery. They also observed a small delay in psychomotor development in the most highly PCB-exposed children, but the effect did not persist beyond 2 years of age. A number of methodological concerns have been raised about the Jacobson study, including issues related to exposure assessment, sample selection, and control of potential confounding variables. However, it is not clear that these shortcomings can explain the discrepancies between their findings and those of Rogan and Gladen. Other possible explanations include differences in exposure levels or PCB congener patterns between the two cohorts, differences in sociodemographic variables between the two cohorts, or other problems inherent in trying to detect subtle neuropsychological deficits at exposure levels that are near the threshold for effects. Hopefully, several new studies that are currently underway will help to resolve the uncertainties regarding the risks of perinatal PCB exposure that have been created by the conflicting results of these early studies.

Polychlorinated biphenyls in small mammals from contaminated landfill sites

PCBs in small mammals living in a contaminated landfill site varied in both concentration and congener composition, reflecting both the feeding strategy of each species and the chlorination of the congeners. Body concentrations of SigmaPCB on a 1:1:1 Arochlor (1242:1254:1260) basis gave a rank order of Sorex araneus >> Apodemus sylvaticus > Microtus agrestis. Comparisons with data for other PCB-contaminated sites suggest that the SigmaPCB values in S. araneus from the landfill site may be of sufficient magnitude to inhibit reproductive capability and to cause other major organ dysfunction. There were also inter-specific differences in the whole body concentrations of the individually quantified congeners. For S. araneus, the rank order of concentrations of the selected ICES 7 marker PCB congeners was: No. 153>138>>180>118>>28>101>52. In M. agrestis the rank order was: No. 28>118>153>138>180, 52>101. The congener order for A. sylvaticus differed from both S. araneus and M. agrestis, but was more similar to the latter, being: No. 153>138>118>180>28>52, 101. The contribution of the different congeners to SigmaPCB in the mammals reflects the degree of chlorination of different congeners but varies with feeding strategy of the species. In the insectivorous S. araneus, heavily chlorinated congeners (Nos 153, 138 and 180) are most abundant, whereas the herbivore, M. agrestis showed congeners Nos 28 and 118 to be present in the highest amounts, whilst the equivalent pattern for the more omnivorous A. sylvaticus was intermediate between S. araneus and M. agrestis. The high concentrations of PCBs in S. araneus relative to the other species, suggests that it may serve as a useful biomarker of terrestrial environmental pollution by organochlorines.