Chlorobiphenyls Research Articles

Specific Features of Chlorinated Biphenyl Decomposition by Rhodococcus wratislaviensis Strain KT112-7 under High Salt Conditions

Rhodococcus wratislaviensis strain KT112-7 (VKM As-2623D) degraded monosubstituted 2-/4-chlorobiphenyls (94.25 mg/L) and 2,4'-dichlorobiphenyl (22.3 mg/L) when the sodium chloride content in the culture medium did not exceed 50 g/L. We have calculated the kinetic parameters of chlorobiphenyl (CB) decomposition by the КТ112-7 strain, which demonstrated decreased decomposition efficiency with increasing NaCl concentration. A linear correlation has been found between the content of saturated, unsaturated, and branched fatty acids in the cell wall of the KT112-7 strain and the NaCl content in the culture medium. The change in the content and composition of fatty acids in the cell wall apparently led to a change in the permeability of the CB cell wall. R. wratislaviensis strain KT112-7 was able to oxidize the unsubstituted ring in 2-CB and 4-CB at all studied NaCl concentrations in the medium and efficiently decomposed the chlorobenzoic acids (CBAs) that formed as a result of the oxidation. Decomposition of 2,4'-CB at low NaCl concentrations in the medium (not higher than 10 g/L) involved the oxidation of the ring substituted by chlorine in the position 4, while the presence of 20–50 g/L of NaCl led to the oxidation of the ring substituted by chlorine in the position 2. The main detected metabolite was 2-chlorobenzoic acid in the former case and 4-chlorobenzoic acid in the latter. The 4-CBA transformation proceeded via the formation of protocatechuic acid (3,4-hydroxybenzoic acid) and catechol at all of the studied sodium chloride concentrations in the medium and through another pathway involving the formation of chlorocatechol at NaCl concentrations of 30, 40, and 50 g/L.

The role of non-spore-forming actinobacteria in cleaning up sites contaminated by persistent pollutants and the ability of these microorganisms to survive under unfavourable conditions

Years of research has shown that actinobacteria, including Rhodococcus, Gordonia, Arthrobacter, Microbacteria, play an important role in cleaning up sites contaminated by persistent organic pollutants. Under special conditions, actinobacteria of different genera are able to form specific forms, cyst-like resting cells (CLC), which maintain the viability during long-term storage (for at least 5–6 years, our unpublished results). These cells quickly germinate when conditions become favourable for growth. As a result, actinobacteria can be used as a basis for creating highly efficient biological preparations for cleaning up the soil with high levels of toxic contaminants such as (chloro)phenols, (chloro)biphenyls, polycyclic hydrocarbons, oil1.

Identification of two organohalide-respiring Dehalococcoidia associated to different dechlorination activities in PCB-impacted marine sediments

BackgroundMicrobial reductive dechlorination of polychlorinated biphenyls (PCBs) plays a major role in detoxifying anoxic contaminated freshwater and marine sediments from PCBs. Known members of the phylum Chloroflexi are typically responsible for this activity in freshwater sediments, whereas less is known about the microorganisms responsible for this activity in marine sediments. PCB-respiring activities were detected in PCB-impacted marine sediments of the Venice Lagoon. The aim of this work was to identify the indigenous organohalide-respiring microorganisms in such environments and assess their dechlorination specificity against spiked Aroclor™ 1254 PCBs under laboratory conditions resembling the in situ biogeochemistry.ResultsHigh PCB dechlorination activities (from 150 ± 7 to 380 ± 44 μmol of chlorine removed kg−1 week−1) were detected in three out of six sediments sampled from different locations of the lagoon. An uncultured non-Dehalococcoides phylotype of the class Dehalococcoidia closely related to Dehalobium chlorocoercia DF-1, namely phylotype VLD-1, was detected and enriched up to 109 16S rRNA gene copies per gram of sediment where dechlorination activities were higher and 25-4/24-4 and 25-2/24-2/4-4 chlorobiphenyls (CB) accumulated as the main tri-/dichlorinated products. Conversely, a different phylotype closely related to the SF1/m-1 clade, namely VLD-2, also enriched highly where lower dechlorination activity and the accumulation of 25-3 CB as main tri-chlorinated product occurred, albeit in the simultaneous presence of VLD-1. Both phylotypes showed growth yields higher or comparable to known organohalide respirers and neither phylotypes enriched in sediment cultures not exhibiting dechlorination.ConclusionsThese findings confirm the presence of different PCB-respiring microorganisms in the indigenous microbial communities of Venice Lagoon sediments and relate two non-Dehalococcoides phylotypes of the class Dehalococcoidia to different PCB dechlorination rates and specificities.

Efficacy of zero-valent copper (Cu0) nanoparticles and reducing agents for dechlorination of mono chloroaromatics

The zero-valent copper (Cu0) nanoparticles were prepared by chemical reduction method. The morphology of nanoparticles was investigated by using X ray diffraction, scanning electron microscopy-energy dispersive X ray, UV–visible spectrophotometer and Brunauer-Emmett-Teller surface area analyser. The Cu0 nanoparticles along with reducing agents, NaBH4/5% acidified alcohol were used for the dechlorination of chloroaromatics at room temperature. Chlorobenzene (Cl-B), chlorotoluene (Cl-T), chloropyridine (Cl-Py) and chlorobiphenyl (Cl-BPh) were selected as the contaminants. The effect of various operating parameters such as pH, concentration of the catalyst and reducing agent (NaBH4), and recycling of the catalyst on dechlorination were studied. Nearly complete dechlorination of all the chloroaromatics were achieved in the presence of Cu0 nanoparticles (2.5 g L−1) and NaBH4 (1.0 g L−1) within 12 h. On the contrary, approximately 70% of dechlorination was observed in the presence of 5% acidified alcohol at similar experimental conditions. The dechlorination mechanism highlighted the importance of Cu0 nanoparticles as a surface mediator. The kinetics of the dechlorination of chloroaromatics was investigated and compared with chloroaliphatics. The dechlorination rate differed from 0.23 h−1 (Cl-B) to 0.15 h−1 (Cl-BPh) in the presence of Cu0 nanoparticles and NaBH4. The effectiveness of Cu0 nanoparticles with NaBH4 (1 g L−1) and 5% acidified alcohol as electron donors were studied by oxidation-reduction potential and observed to be −1016 mV and −670 mV, respectively. Final products of the dechlorination were benzene, toluene, pyridine and biphenyl, as identified by gas chromatograph mass spectrometer and nuclear magnetic resonance spectroscopy.

Congener Selectivity During Polychlorinated Biphenyls Degradation by Enterobacter sp. LY402

The relationship between the selectivity of a particular polychlorinated biphenyls (PCBs) congener and its biodegradability under the same concentration, especially by Enterobacter sp. LY402, is less well studied. To measure congener selectivity of Enterobacter sp. LY402, several influencing factors were studied. The results showed LY402 effectively degraded coplanar 3,4,3',4'-chlorobiphenyl (CB) at a concentration of 0.05 μM, but not 0.5 μM. The degradation rates of 2,4,5,2',3'-CB and 2,4,5,2',4',5'-CB were increased significantly when the sample constituents were changed from 12 to 5 congeners or to one congener. This indicated that bioremediation of individual congener was affected by other congeners present in the mixture. Moreover, for PCBs containing one chlorine on each phenyl ring, the reactivity preference of LY402 was 2,2'-CB ≥ 3,3'-CB ≫ 4,4'-CB. For two ortho chlorines congeners of PCBs, 2,2'-CB was degraded faster than 2,6-CB. Although 2,6-CB and 4,4'-CB were poorly degraded, the addition of one (i.e., 2,4,4'-CB and 2,6,3'-CB) or two more chlorines (i.e., 2,4,2',4'-CB) on the phenyl ring significantly increased their biodegradability. In addition, comparing the two congeners of ortho-meta-chlorinated biphenyl, 2,3,2',3'-CB with neighbor meta chlorines was degraded slower than 2,5,2',5'-CB with interval meta chlorines. All these indicated that the transformation rates of PCBs were not consistent with the number of chlorines, and PCBs containing the same numbers of chlorines but at different positions also resulted in different conversions. In principle, the extents of effect caused by the position of chlorine substituents on the degradation of PCBs by LY402 were ortho- > meta- > para-CB. In conclusion, the congener selectivity of LY402 was determined by many factors, including the composition of the congeners, their concentrations in the mixture and location and number of chlorine substituents on the phenyl rings.

Halogenated persistent organic pollutants in Scottish deep water fish

Halogenated persistent organic pollutants (chlorobiphenyls (CBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD) and tetrabromobisphenol-A (TBBP-A)) and total lipid content were measured in the liver and muscle of three species of deep water fish (black scabbard, roundnose grenadier and black dogfish) collected from the Rockall Trough, to the west of Scotland, in 2006. CB concentrations (SigmaICES (International Council for the Exploration of the Seas)7 CBs) >500 microg kg(-1) lipid weight) were found in 9 of the 31 deep water fish liver samples. Non-ortho CBs were measured in samples with the highest ortho CB concentrations. Non-ortho CBs (CB81, 77, 126 and 169) were not detected in any of the fish muscle samples. In liver, CB81 was not detected in any of the samples while CB169 was detected in all but one sample. The total 'dioxin-like' CB concentration was calculated based on the 5 mono-ortho and 4 non-ortho CBs measured. The non-ortho CB concentration made a very small contribution to the total 'dioxin-like' CB concentrations (<1%). Concentrations for the individual ICES7 CBs in fish liver were above OSPAR Background Assessment Concentrations (BACs) in all three species, except for CB28 and 101 in black dogfish. Toxic Equivalent (TEQs) concentrations calculated for the five mono-ortho and four non-ortho CBs measured, and estimated TEQs calculated using published models in the fish muscle indicated that consumption of deep water fish muscle is unlikely to represent a risk to human health. However, dioxins and furans were not measured and the contribution to the calculated TEQs from these compounds was not taken into account. Calculated and estimated TEQs for some roundnose grenadier liver samples exceeded the 25 pg g(-1) wet weight limit for fish liver and, therefore, there may be a health risk if consumed. PBDEs were detected in both the liver and muscle of the deep water fish, whilst HBCD and TBBP-A were not detected in any of the deep water fish.

An assessment of persistent organic pollutants (POPs) in wild and rope grown blue mussels (Mytilius edulis) from Scottish coastal waters

Farmed, rope grown mussels (Loch Etive and Loch Ewe, both on the west coast of Scotland) and wild mussels (Straad on the west coast and Shell Bay and Aberdeen Breakwater, both on the east coast of Scotland) were collected on a monthly basis and analysed for persistent organic pollutants (POPs) with the aim of assessing the status of Scottish mussels, with respect to concentrations of POPs, and investigating site-specific and seasonal differences. Samples were analysed for polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs) and chlorobiphenyls (CBs). Total PAH (2- to 6-ring parent and alkylated) concentrations in mussels from three pristine sites (ref. 1: ICES Marine Chemistry Working Group Report 2008, http://www.ices.dk/reports/MHC/2007/MCWG07.pdf) (Loch Etive, Loch Ewe and Straad) were significantly lower than in mussels from sites with greater coastal influences (Aberdeen Breakwater and Shell Bay). Seasonal trends in the PAH concentrations were evident at the pristine sites, with concentrations being significantly higher for samples collected between November and March compared to those collected between April and October. The PAH data was assessed using a recently proposed traffic light system, based on the assessment criteria adopted by OSPAR for use in the 2008 Coordinated Environmental Monitoring Programme (CEMP) assessment. Concentrations were compared to Background Assessment Concentrations (BAC; blue/green transition) and Environmental Assessment Concentrations (EACs; green/red transition). All sites were classed as 'green' for the PAHs analysed, being below EACs, where available. The pristine sites were also below BACs for some PAHs and therefore would be classed as 'blue' for these PAHs. CBs and PBDEs were measured in mussels collected between 2006 and 2008 inclusive. Concentrations for CB and PBDEs were significantly higher in the Aberdeen Breakwater mussels than for all other sites. Concentrations at all sites were low with many congeners being below the detection limits for both contaminant groups. No seasonal trends were observed in the CBs or PBDE concentrations or composition at any of the five sites. The green-red transition (described by the EACpassive) was exceeded for CB118 in mussels from Aberdeen Breakwater and surprisingly at the pristine site of Loch Etive. As such both sites were classed as 'red'. All other ICES7 CBs were below EACs and therefore classed as 'blue' or 'green'.

Measurement of atmospheric deposition of polychlorinated biphenyls and their dry deposition velocities in an urban/industrial site in Turkey

Dry deposition fluxes and total (gas+particle) concentrations of polychlorinated biphenyls (PCBs) were measured between August 2004 and May 2005. Samples were collected from an urban-industrial site of Bursa, Turkey. A stainless steel pot and a high volume air sampler (HVAS) were employed to collect deposition and ambient air samples, respectively. The dry deposition fluxes of PCBs ranged from 3600 to 56,000 pg m−2 d−1 while the total PCB concentrations collected simultaneously were between 35 and 348 pg m−3. The average dry deposition flux value was in line with the previously reported values. Possible variations in PCB fluxes were likely due to PCB and total suspended particle (TSP) concentrations, and meteorological conditions. No seasonal trends were observed for the bulk deposition samples. The 3- and 4- chlorobiphenyls (CBs) were abundant homolog groups in bulk and concentration samples with ratios of 67% and 90%, respectively. Apparent bulk deposition velocities were calculated by dividing the dry deposition flux value by particle phase air concentration values of PCBs measured with HVAS. The calculated apparent dry deposition velocities ranged from 0.23 cm s−1 to 3.09 cm s−1 (aver ± SD, 0.74 ± 0.23 cm s−1).

Bone Mineral Density Changes in Relation to Environmental PCB Exposure

BackgroundBone toxicity has been linked to organochlorine exposure following a few notable poisoning incidents, but epidemiologic studies in populations with environmental organochlorine exposure have yielded inconsistent results.ObjectivesThe aim of this study was to investigate whether organochlorine exposure was associated with bone mineral density (BMD) in a population 60–81 years of age (154 males, 167 females) living near the Baltic coast, close to a river contaminated by polychlorinated biphenyls (PCBs).MethodsWe measured forearm BMD in participants using dual energy X-ray absorptiometry; and we assessed low BMD using age- and sex-standardized Z-scores. We analyzed blood samples for five dioxin-like PCBs, the three most abundant non-dioxin-like PCBs, and p,p′-dichloro-phenyldichloroethylene (p,p′-DDE).ResultsIn males, dioxin-like chlorobiphenyl (CB)-118 was negatively associated with BMD; the odds ratio for low BMD (Z-score less than −1) was 1.06 (95% confidence interval, 1.01–1.12) per 10 pg/mL CB-118. The sum of the three most abundant non-dioxin-like PCBs was positively associated with BMD, but not with a decreased risk of low BMD. In females, CB-118 was positively associated with BMD, but this congener did not influence the risk of low BMD in women.ConclusionsEnvironmental organochlorine exposures experienced by this population sample since the 1930s in Sweden may have been sufficient to result in sex-specific changes in BMD.

Dioxin-like compound load in bulk of Chlorofen–A technical chlorobiphenyl formulation from Poland

The results from inventory aiming to quantify production of individual chlorobiphenyl (CB) constituents and by-product impurities such as chlorodibenzo-p-dioxins (CDDs), chlorodibenzofurans (CDFs) and chloronaphthalenes (CNs) contained in the bulk of manufactured Chlorofen presented. 2,2′,3,4,4′,5,5′-Heptachlorobiphenyl (#180) is the most abundant constituent of Chlorofen and its historical production is estimated as 210 tones, and followed in decreasing order other major constituents are 2,2′,3,3′,4,4′,5′,6-/2,2′,3,4,4′,5,5′,6-OcCB (#196/203), 2,2′,3,3′,4,4′,5,5′-OcCB (#194), 2,2′,3,3′,4,5,6,6′-OcCB (#200) 2,2′,3,3′,4,5′,6-HpCB (#175), 2,2′,3,3′,4,5,5′,6-OcCB (#198) 2,2′,3,3′,4,5,5,′6′-OcCB (#199), 2,2′,3,3′,4,5′,6-HpCB (#175), 2,2′,3,4,5,5′,6-HpCB (#185) and 2,2′,4,4′,5,5′-HxCB (#153), which contributed from 150 to 53 tones, respectively. Production of non-ortho CBs was 30.277 kg with 23 kg input from 3,3′4,4′,5-PeCB (#126), while of mono-ortho CBs was 390 kg with 200 kg input from 2,3′,4,4′,5-PeCB (#118). 3,3′4,4′,5-PeCB (#126) and 3,3′,4,4′,5,5′-HxCB (#169) with 2300 and 99 g of dioxin TEQ were major dioxin-like contributors among planar CBs in this formulation. CDDs and CDFs content of the bulk of Chlorofen was estimated as 0.11 and 319 kg, respectively, and the most toxic members are 0.355 and 99.6 g TEQ. 1,2,3,4,5,6,7-HpCN (#73) with 5.3 kg (53 g TEQ) 1,2,3,4,5,6,8-HpCN (#74) with 2.9 kg (29 g TEQ) and OCN with 370 kg (37000 g TEQ) dominated among CNs in bulk of Chlorofen. An especially large contribution form OCN is due to its relatively high extrapolated REP value and absolute concentration value reported.

The determination of gas phase dry deposition fluxes and mass transfer coefficients (MTCs) of polychlorinated biphenyls (PCBs) using a modified water surface sampler (WSS)

Gas phase PCB dry deposition and concentration samples were collected simultaneously between July 2004 and May 2005 at a suburban site in Bursa, Turkey. A modified water surface sampler (WSS) was employed to collect gas phase fluxes while a high-volume air sampler (HVAS) was used for concentration samples. The WSS was able to collect both particle and gas phase PCB deposition samples. The collected PCBs on water surface were captured by a filter and an XAD-2 resin column during water cycle. The average of gas phase PCB deposition flux, determined by analyzing the XAD-2 resin column, was 79.3+/-40.5 ng m(-2) d(-1) and its percentage in total (gas+particle) PCB flux was about 60. The average of gas phase PCB concentration measured concurrently with flux samples was 224.4+/-160.2 pg m(-3) and its ratio to the total (gas+particle) PCB concentration was 85%. This difference was likely due to the different deposition characteristics of gases and particulates. Dominant PCB homolog groups were 3-4 chlorobiphenyls (CBs) for both ambient air and gas phase deposition samples. Mass transfer coefficients (MTC, K(g)) for air-side were determined using gas phase flux and ambient air concentration values. The average overall K(g) ranged between 0.21 and 0.96 cm s(-1) with an average of 0.60+/-0.19 cm s(-1).

Generation by a Widely Applicable Approach of a Hybrid Dioxygenase Showing Improved Oxidation of Polychlorobiphenyls

Recently, a sequence-based approach has been developed for the fast isolation and characterization of class II aryl-hydroxylating dioxygenase activities (S. Kahl and B. Hofer, Microbiology 149:1475-1481, 2003). It comprises the PCR amplification of segments of alpha subunit genes of unknown sequence that encode the catalytic center and their fusion with sequences of the bphA gene cluster of Burkholderia xenovorans LB400. One of the resulting chimeric enzymes, harboring the core segment of a dioxygenase from Pseudomonas sp. strain B4-Magdeburg, has now been characterized with respect to the oxidation of chlorobiphenyls (CBs). Its substrate and product specificities differed favorably from those of the parental dioxygenase of strain LB400. The hybrid possessed a higher regiospecificity and yielded less unproductive dioxygenations at meta and para carbons. It attacked ortho-, meta-, and para-chlorinated rings with comparable efficiencies. It gave significantly higher yields in ortho,meta-dioxygenation of recalcitrant congeners containing a doubly ortho-chlorinated ring. While the parental enzyme yielded mainly unproductive meta, para dioxygenation of 2,5,4'-CB, the hybrid predominantly converted this congener into an ortho,meta-dioxygenated product. The subsequent enzymes of the LB400 catabolic pathway were able to transform most of the metabolites formed by the novel dioxygenase, indicating that the substrate ranges of these biocatalysts are not adapted to that of their initial pathway enzyme. Some of the catabolites, however, were identified as problematic for further degradation. Our results demonstrate that the outlined approach can successfully be applied to obtain novel dioxygenase specificities that favorably complement or supplement known ones.

Measurement of organic contaminants and biological effects in Scottish waters between 1999 and 2005

Concentrations of organic contaminants were determined in sediment and fish collected annually at six sites around Scotland between 1999 and 2005, as part of the UK National Marine Monitoring Programme. Polycyclic aromatic hydrocarbons (PAHs) and chlorobiphenyls (CBs) were measured in sediment, while CBs and ethoxyresorufin-O-deethylase (EROD) activities were measured in the fish. Highest PAH concentrations in sediment were found at sites where higher coastal influences would be expected (e.g., Clyde and Solway) and four of the six sites gave PAH concentrations above OSPAR background assessment concentrations (BACs). A significant downward trend in the median total PAH concentrations, normalised to total organic carbon (TOC), was found at one of the six sites (Minches). The PAH profiles at all sites were consistent over the 6 year period, indicating that the sites are relatively stable and PAH sources are not changing. There was an indication of a greater petrogenic input on the west coast, with sediment from the Clyde, Solway and Minches having a greater proportion of 2- and 3-ring PAHs and a lower proportion of 5-ring PAHs. CB concentrations at all sites were low compared with UK estuarine sites and similar to sediment from more remote areas: however, BACs were exceeded. No significant trends were detected in either the sediment CB concentrations or patterns at any of the six sites. CB concentrations were significantly higher in fish liver collected from the Clyde. Concentrations at the other five sites were low, with the majority of samples having concentrations for the ICES7 CBs of <500 microg kg(-1) lipid weight. However, individual CB concentrations were still above the BACs. Hepatic EROD activities were measured in male plaice from 2002-2005 and were generally low (<10 pmol min(-1) mg protein(-1)). No temporal trends were detected in either CB concentrations or the EROD activity.

Passive sampling: partition coefficients for a silicone rubber reference phase

Silicone rubber sheeting can be used as a passive sampling device for hydrophobic organic contaminants in the environment to determine the available concentrations in water and sediments. Reliable sampler-water partition coefficients are required to determine the sampling rates and the dissolved contaminant concentrations in water and in sediment pore water. Log partition coefficients (logK(sr,w)) for silicone rubber-water have been estimated for 32 polycyclic aromatic hydrocarbons (PAHs), 2 deuterated PAH analogues and 32 chlorobiphenyls (CBs) using the cosolvent method, with methanol as cosolvent. Strong linear relationships were found with literature values for the corresponding log octanol-water partition coefficients (logK(ow)) for both CBs and PAHs, confirming that partitioning into the silicone rubber is strongly determined by the hydrophobicity of the compounds, which suggests logK(ow) is a good predictor of logK(sr,w) and that absorption is the main mechanism for accumulation of analytes into the silicone rubber polymer.

Polybrominated diphenyl ethers (PBDEs) in mussels from selected French coastal sites: 1981–2003

The present study focused on the retrospective analysis of PBDEs in archived blue mussel ( Mytilus edulis or Mytilus galloprovincialis) samples collected over the past 22 years (1981–2003) from coastal areas of France. We have found that PBDE levels in mussels from the English Channel increased markedly from 1981 to 1991–1995, doubling ≈ every 5–6 years followed by a levelling off and a possible beginning of a decrease. The rate of the decline of hexa- and hepta-BDE congeners was more rapid than the decline of tetra- and penta-BDEs in these mussel samples. The difference in the course of time of lower and higher brominated PBDE concentrations suggests that the congener profile in the mussel samples changes over time. The increase in PBDE concentrations in the mussel samples contrasts with a concomitant constant decrease of chlorobiphenyls (CBs) in the same set of samples. However, pulse inputs of both groups of organohalogen compounds were determined for the mussel samples collected at the mouth of the Seine estuary and were probably related to riverine inundations and a flushing out of the deposited sediments from the internal estuary into the bay of the River Seine, as well as considerable dredging activities taking place during same years. In France, the highest PBDE concentrations were determined in the mussels from the English Channel, more precisely in the bay of the Seine, and the regional differences in PBDE levels were mainly connected to the difference in anthropogenic urban and industrial environmental pressures. Published data comparing PBDE levels in mussels have shown significant differences in concentrations between North/South America and Europe. This observation further confirms that the PBDE levels in the North American environment are higher than in Europe. However, the data used for this comparison of mussel contamination by PBDEs is still relatively sparse.

By-Side Chlorobenzenes and Chlorophenols in Technical Chlorobiphenyl Formulations of Aroclor 1268, Chlorofen, Clophen T 64, Kanechlor 600, and Kanechlor 1000

All 19 possible chlorophenol (CPh) and 12 chlorobenzene (CBz) congeners as potential impurities or additive were quantified in a relatively highly chlorinated type of technical chlorobiphenyl (CB) mixtures of Aroclor 1268, Chlorofen, Clophen T 64, Kanechlor 600, and Kanechlor 1000 using isotope dilution technique and HRGC/HRMS. The total CBzs content of Aroclor 1268, Chlorofen and Clophen T 64, Kanechlor 600, and Kanechlor 1000 was 0.039, 0.5, 230, 0.068, and 400 mg/g, respectively, while of CPhs was < 0.007, 0.48, 10, 0.093, and 0.98 μg/g. All 12 congeners of chlorobenzene could be quantified in all the formulations examined, but their proportions varied largely. It seems that stockpiles of technical chlorobiphenyl formulations and hazardous wastes containing CBs, both with added and/or by-side CBzs are also a somehow forgotten source of environmental contamination with those environmentally relevant compounds. No CPhs were found in Aroclor 1268 (< 7 ng/g). 2-MoCPh, 2,6-DiCPh, 3,5-DiCPh, 3,4,5-TrCPh, and 2,3,4,5,6-PeCPh were absent (< 1– < 20 ng/g) in Chlorofen and Clophen T 64, while other chlorophenol congeners were found at concentration from 7.4 to 130 and from 9.9 to 8,800 ng/g, respectively. Then, 3- and 4-chlorophenol, which co-eluted, were main contributors (88%) to the total CPhs content of Clophen T 64, while 2,3,4,6-TeCPh with 27% abundance was a major congener among CPhs in Chlorofen. Then, 2,4,6-TrCPh was the most abundant congener in Kanechlor 600, while 2,4,5-TrCPh was the most abundant congener in Kanechlor 1000.

Chlorobiphenyl Constituents of Aroclor 1268, Chlorofen, Clophen T 64, KC-600, and KC-1000 Technical Formulations

All 209 chlorobiphenyls (CBs) theoretically possible and potentially present in relatively highly chlorinated types of technical CB formulations of Aroclor 1268, Chlorofen, Clophen T 64, KC-600, and KC-1000 have been quantified using isotope dilution techniques and high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). CB constituents of Aroclor 1268, Chlorofen, Clophen T 64, KC-600, and KC-1000 could be separated, detected, identified and quantified as “bulk CBs,” using a capillary column (60 m length × 0.25 mm i.d.) coated by 8% phenyl polycarborane-siloxane (HT-8PCB, SGE, Australia) liquid phase for GC coupled to HRMS, into 111, 78, 126, 137, and 148 peaks, respectively, which covered 140, 100, 158, 169, and 180 possible CB congeners. 87, 60, 99, 110, and 121 peaks represented single CB congeners in Aroclor 1268, Chlorofen, Clophen T 64, KC-600, and KC-1000, respectively, while 34, 18, 27, 27, and 27 peaks represented 53, 40, 59, 59, and 59 co-eluting CBs. After enrichment procedures using multilayer silica beds, alumina beds, and carbon-impregnated silica beds in glass columns, all four planar non-ortho CBs and all eight mono-ortho CBs (but with the exception of CB no. 123 in Chlorofen) could be quantified in all five technical CB formulations examined. The planar non- and mono-ortho CBs content of Aroclor 1268, Chlorofen, Clophen T 64, KC-600 and KC-1000 were 6.2, 7.0, 47, 120, 470 μ g/g and 220, 410, 34,000, 12,000, 5900 μ g/g, respectively, and their 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity equivalents (2,3,7,8-TeCDD TEQs) were 31, 390, 710, 260, 1900 ng-TEQ/g and 35, 99, 5900, 2600, 8900 ng-TEQ/g, and the total 2,3,7,8-TeCDD TEQs of planar CBs were 66, 490, 6600, 2900, and 11,000 ng-TEQ/g.

Congener-Specific Carbon Isotopic Analysis of Technical PCB and PCN Mixtures Using Two-Dimensional Gas Chromatography−Isotope Ratio Mass Spectrometry

Analysis of stable carbon isotope fractionation is a useful method to study the sources and fate of anthropogenic organic contaminants such as polychlorinated biphenyls (PCBs) in the environment. To evaluate the utility of carbon isotopes, determination of isotopic ratios of 13C/12C in source materials, for example, technical PCB preparations, is needed. In this study, we determined delta13C values of 31 chlorobiphenyl (CB) congeners in 18 technical PCB preparations and 15 chloronaphthalene (CN) congeners in 6 polychlorinated naphthalene preparations using two-dimensional gas chromatography-combustion furnace-isotope ratio mass spectrometry (2DGC-C-IRMS). Development of 2DGC-IRMS enabled improved resolution and sensitivity of compound-specific carbon isotope analysis (CSIA) of CB or CN congeners. Delta13C values of PCB congeners ranged from -34.4 (Delors) to -22.0/1000 (Sovol). Analogous PCB preparations with similar chlorine content, but different geographical origin, had different delta13C values. PCB preparations from Eastern European countries--Delors, Sovol, Trichlorodiphenyl, and Chlorofen--had distinct delta13C values. PCB mixtures showed increased 13C depletion with increasing chlorine content. Delta13C values for individual CB congeners varied depending on the degree of chlorination in technical mixtures. Delta13C values of CN congeners in Halowaxes ranged from -26.3 to -21.7/1000 and these values are within the ranges observed for PCBs. This study establishes the range of delta13C values in technical PCB and PCN preparations, which may prove to be useful in the determination of sources of these compounds in the environment. This is the first study to employ 2DGC-IRMS analysis of delta13C values in technical PCB and PCN preparations.

Organic contaminants in the Firth of Clyde following the cessation of sewage sludge dumping

To assess contaminant concentrations in the Firth of Clyde in relation to the former sewage sludge dump site at Garroch Head, and investigate any temporal changes, fish have been sampled annually since 1992 and sediment since 1999. In addition, a further four locations in the Clyde (Holy Loch, Hunterston, Skelmorlie and Irvine Bay) have been sampled for fish and sediment since 1999. Chlorobiphenyls (CBs) were measured in fish samples and polycyclic aromatic hydrocarbons (PAHs) and CBs in sediment. Since sampling was initiated the concentration for the summation operatorICES7 CBs in fish liver has been consistently >500 microg kg(-1) lipid weight at Garroch Head and the other Clyde sites and lower at the reference sites (Pladda, Colonsay, Broad Bay). Although the lowest CB concentrations of the eleven year period in plaice liver from Garroch Head were found in 2002, CB concentrations were found not to have decreased significantly since sewage sludge dumping ceased in 1998. However, a change in CB profile was observed with fish liver collected between 1992 and 1998 from Garroch Head showing a lower proportion of the less chlorinated CBs compared to the 1999-2002 liver samples. Highest CB and PAH concentrations in sediment were found at Garroch Head and Holy Loch with concentrations at these sites being significantly higher than at all other sites.

Clophen A60 Composition and Content of CBs, CNs, CDFs, and CDDs after 2D-HPLC, HRGC/LRMS, and HRGC/HRMS Separation and Quantification

Chlorobiphenyl (CB) and by-side chlorodibenzofuran (CDF), chlorodibenzo-p-dioxin (CDD), and chloronaphthalene (CN) homologue group and congener composition, and concentrations have been examined in technical CBs mixture Clophen A60. 101 peaks representing 116 CB congeners were quantified in Clophen A60, and most contributing were CBs nos. 138, 153, 134/144/149, and 180 with 15.4, 12.3, 8.2, and 6.5%, respectively. Di-, tri-, tetra-, penta-, hexa-, hepta-, and octa-CBs constituted, respectively, 0.03, 0.03, 0.32, 9.9, 52.7, and 4.9% of chlorobiphenyls content of the Clophen A60, while mono-, nona-, and decaCB were not quantified. Tetra- to octaCDDs were absent in Clophen A60 at concentration above the method limit of quantification of <0.01 μg/g, while the total CDFs and CNs were found at 12 and 42 μg/g, respectively. Tetra-, penta-, hexa-, and hepta-CDF with 27, 46, 19, and 7% contribution, respectively, dominated in homologue group profile of CDFs, while octa-CDF was absent in Clophen A60. In compositional profile of CDF congeners the most abundant were 1,2,4,7,8-PeCDF, 2,3,4,7,8-PeCDF, and 1,2,3,4,7,8-HxCDF and each had >5% contribution. Amongst the CN homologue groups the profile in descending order followed by hepta-, hexa-, octa-, and penta-CNs with 56, 26, 16, and 2%, respectively. In compositional profile of CNs the most abundant were the congeners such as 1,2,3,4,5,6,7-HpCN (no. 73), 1,2,3,4,6,7-/1,2,3,5,6,7-HxCN (nos. 66/67), and 1,2,3,4,5,6,7,8-OcCN (no. 75) with 55, 21, and 16%, respectively. In terms of dioxin-like toxicity of Clophen A60 the contribution from planar non-ortho and mono-ortho CBs, CDFs, and CNs was 5280, 594.5, and 33.1 ng TCDD TEQ/g, respectively, and the total TEQ of planar analogues was 5908 ng/g.