Commercial PCBs Research Articles

Residue of Dioxin-Like Polychlorinated Biphenyls (DL-PCBs) in Sediment from CauBay River, Vietnam

An evaluation of dioxin-like polychlorinated biphenyls (DL-PCBs) contamination in sediment from CauBay River was carried out. Ten representative sediment samples were collected in April 2013. The analyzed results indicated the wide occurrence of contamination of DL-PCBs in the CauBay River. In industrial and urban sampling sites, ΣDL-PCB concentrations ranged from 14,254 to 17,369 ng·kg -1 dw, while those in agricultural sampling sites ranged from 9,398 to 13,793 ng·kg -1 dw. The value of (PCB126+PCB169)/ (PCB77+PCB126+PCB169) in CauBay River ranged from 10.9% to 16.1%, suggesting that the DL-PCBs in CauBay river are attributable to both commercial PCBs and pyrogenic sources. The total TEQ value of DLPCBs in the CauBay sediment samples ranged from 5.3 to 11.9 ng TEQ·kg -1 dw. Due to the propensity of DLPCBs to accumulate in various compartments of environment, further evaluation of ecotoxicology should be undertaken as a high priority.

Enhanced Reductive Dechlorination of Polychlorinated Biphenyl Impacted Sediment by Bioaugmentation with a Dehalorespiring Bacterium

Anaerobic reductive dehalogenation of commercial PCBs such as Aroclor 1260 has a critical role of transforming highly chlorinated congeners to less chlorinated congeners that are then susceptible to aerobic degradation. The efficacy of bioaugmentation with the dehalorespiring bacterium Dehalobium chlorocoercia DF1 was tested in 2-L laboratory mesocosms containing sediment contaminated with weathered Aroclor 1260 (1.3 ppm) from Baltimore Harbor, MD. Total penta- and higher chlorinated PCBs decreased by approximately 56% (by mass) in bioaugmented mesocosms after 120 days compared with no activity observed in unamended controls. Bioaugmentation with DF-1 enhanced the dechlorination of doubly flanked chlorines and stimulated the dechlorination of single flanked chlorines as a result of an apparent synergistic effect on the indigenous population. Addition of granulated activated carbon had a slight stimulatory effect indicating that anaerobic reductive dechlorination of PCBs at low concentrations was not inhibited by a high background of inorganic carbon that could affect bioavailability. The total number of dehalorespiring bacteria was reduced by approximately half after 60 days. However, a steady state level was maintained that was greater than the indigenous population of putative dehalorespiring bacteria in untreated sediments and DF1 was maintained within the indigenous population after 120 days. The results of this study demonstrate that bioaugmentation with dehalorespiring bacteria has a stimulatory effect on the dechlorination of weathered PCBs and supports the feasibility of using in situ bioaugmentation as an environmentally less invasive and lower cost alternate to dredging for treatment of PCB impacted sediments.

Characteristics of the abundance of polychlorinated dibenzo- p-dioxin and dibenzofurans, and dioxin-like polychlorinated biphenyls in sediment samples from selected Asian regions in Can Gio, Southern Vietnam and Osaka, Japan

The levels of polychlorinated dibenzo- p-dioxin and dibenzofuran (PCDD/PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs) were determined in sediment samples from Can Gio, South Vietnam, and Osaka, Japan. Can Gio is known for the defoliation of its mangrove forests by aerial spraying with Agent Orange during the Vietnam War, whereas Osaka is renowned for a PCDD/PCDF pollution accident at a municipal solid-waste incinerator. For comparison, we also analyzed PCDD/PCDFs and DL-PCBs in sediment samples from Hue and Hanoi, Vietnam. The toxic equivalent quantity (TEQ) values in Can Gio were as high as those in Hue, Hanoi, and suburban areas of Osaka, but much lower than those in urban areas of Osaka. The proportion of the World Health Organization (WHO)-TEQ value contributed by 2,3,7,8-tetrachlorinated dibenzo- p-dioxin (TCDD) in Can Gio was approximately 30%, higher than the values in the other sample areas. These data suggest that residual sedimentary TCDD that originated from aerial spraying of Agent Orange occur in only low concentrations in Can Gio. The main contributors to WHO-TEQ values in Can Gio are natural sources, as in Hue. In contrast, commercial PCBs are the dominant contributors to WHO-TEQ values in Hanoi. In Osaka, agrochemicals used in rice cultivation, the incineration of solid waste, and commercial PCBs equally contributed to WHO-TEQ values at suburban locations. The dumping of incinerator-related materials and/or the inadequate management of commercial PCBs have resulted in significantly elevated WHO-TEQ values of 240–370 ng kg –1 dw at urban locations in Osaka.

Survey on organochlorine pesticides, PCDD/Fs, dioxin-like PCBs and HCB in sediments from the Han river, Korea

The contamination status of twelve persistent organic pollutants (POPs) on the Stockholm convention in the surface sediments of Han river, which is one of the largest river in the South Korea were investigated. Five organochlorine pesticides (OCPs) such as aldrin, dieldrin, endrin, mirex, and ΣCHLs (α-chlordane, γ-chlordane, cis-nonachlor, trans-nonachlor, and heptachlor) were not detected in all sediment samples. The overall concentrations of DDTs, HCB, dioxin-like PCBs (DL-PCBs) and PCDD/Fs were in the range of 1.05–8.94μgkg−1 (average value: 3.93μgkg−1), 0.485–3.73μgkg−1 (1.48μgkg−1), 41.5–4,530ngkg−1 (548ngkg−1), and 23.1–368ngkg−1 (131ngkg−1), respectively. The principal source of HCB, DL-PCBs and PCDD/Fs was identified as a deposition in this study. For the DL-PCBs, it was also shown that commercial PCBs product (Kanechlor 500 and/or Aroclor 1254) plays a role as a source in sediment.

Environmental impact and human exposure to PCBs in Guiyu, an electronic waste recycling site in China

PCB levels in fish (collected from local rivers), atmosphere and human milk samples have been studied to determine the exposure levels of PCBs for local residents and e-waste workers in Guiyu, a major electronic waste scrapping center in China. The source appointment and correlation analyses showed that homologue composition of PCBs in 7 species of fish were consistent and similar to commercial PCBs Aroclor 1248. PCB levels in air surrounding the open burning site were significantly higher than those in residential area. Inhalation exposure contributed 27% and 93% to the total body loadings (the sum of dietary and inhalation exposure) of the local residents, and e-waste workers engaged in open burning respectively. Total PCB concentrations in human milk ranged from N.D. to 57.6 ng/g lipid, with an average of 9.50 ng/g lipid. The present results indicated that commercial PCBs derived from e-waste recycling are major sources of PCBs accumulating in different environmental media, leading to the accumulation of high chlorinated biphenyls in human beings.

Determining Sources of Atmospheric Polychlorinated Biphenyls based on Their Fracturing Concentrations and Congener Compositions

Air samples collected at 23 sites in Kanagawa Prefecture, Japan in 1998 and 1999 were analyzed for PCBs by a high-resolution gas chromatograph/mass spectrometer. Concentrations of PCBs ranged from 10 to 3290 pg/m3 N (geometric average, 120 pg/m3N) and were mostly less than 140 pg/m3 N. The toxicity equivalency quantity (TEQ) values of co-planar PCBs ranges from not detected (ND) to 0.35 pg-TEQ/m3 N (mean value, 0.00063 pg-TEQ/m3 N). Cl3-PCBs comprised the highest level in many air samples. PCB congeners in the samples collected on three consecutive days did not vary significantly, suggesting that variation of PCBs concentrations is minimal among the samples collected at same sites. On the other hand, the pattern similarities of PCBs in the samples collected at various areas were not consistent. Contamination from commercial PCBs (Kaneclor) was observed in some samples with high PCBs concentrations. The compositions of PCB congeners in the samples collected at the sites near municipal waste incinerators were similar to those of PCB congeners in the samples collected at common environments in Japan, whereas they were completely different from those in the exhaust gases collected directly from municipal waste incinerators. Consequently, contribution of exhaust gases from incinerators to PCB concentrations and/or compositions of all air samples collected in the present study was not observed.

東京湾流入河川におけるダイオキシン類の輸送量と発生源

The amounts of dioxins (PCDD/Fs) and dioxin-like PCBs transported by rivers from various sources to Tokyo Bay were estimated. River water samples were collected at six stations in six different rivers (Edo River, Naka River, Ara River, Sumida River, Tama River and Tsurumi River) from April 2001 to July 2003, and the concentrations of PCDD/Fs and dioxin-like PCBs in these rivers were determined. On the basis of these results, the annual amounts of PCDD/Fs and dioxin-like PCBs transported by each river to Tokyo Bay were estimated. It was estimated that 10 g-TEQ (particulate phase) and 2.3 g-TEQ (dissolved phase) were transported to Tokyo Bay annually in recent years. Also, the contributions of sources of PCDD/Fs and dioxin-like PCBs in these rivers were estimated by a chemical mass balance (CMB) approach. In Tama and Tsurumi Rivers, it was estimated that more than 85% of total TEQ originated from combustion, while the contribution of combustion was less than 60% in the Ara River. Moreover, the amounts of PCDD/Fs and dioxin-like PCBs transported from each source were estimated, assuming that the contributions of sources in a river are constant in recent years. It was estimated that 8.4 g-TEQ, 1.1 g-TEQ, 0.45 g-TEQ, 1.2 g-TEQ originating from combustion, PCP, CNP and commercial PCBs, respectively, were transported to Tokyo Bay annually.

Concentrations and Profiles of Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans in Soils from Korea

Soil samples were collected from Changwon and Masan Cities, Korea, and analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs). Nearly all tetra- through octachlorinated PCDDs/DFs including the 17 2,3,7,8-substituted PCDDs/DFs were detected in all samples. Total concentrations of PCDDs/DFs and of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TeCDD) equivalents (TEGs) in soils ranged from 35 to 121,400 pg/g, dry weight, and from 0.2 to 3720 pg of I-TEQ/g, respectively. On the basis of guidelines for TEQ concentrations established in Germany and the United States, 9 of 23 soil samples (39% of the total samples analyzed) could not be expected to pose human health hazards. The rest of 61% of soils need measures such as investigations of source identification, soil decontamination, and/or soil removal. Total concentrations of PCDDs/DFs were greater at or near four industrial sites, which are concerned with the steel industry, petrochemical-related industry, and industrial waste incineration, than other areas. This indicates the presence of potential source areas. Soil collected from a site 50 m from an open-burning industrial waste incinerator in an industrial complex was heavily contaminated, containing a total concentration of PCDDs/DFs of 121,400 pg/g, dry weight. PCDDs/DFs were also detected in soils from the top of a 200 m mountain indicating a wide dispersal of PCDDs/DFs by atmospheric transport from point source areas. The congener pattern and relative proportions of PCDFs in soils suggest that commercial PCB preparations such as Kanechlors may be one of the sources. The wide range of PCDD/DF isomers detected in soils from many locations also suggests a multitude of sources, in addition to commercial PCBs, such as incineration of industrial wastes such as car tires, scrap wires, plastics, papers, and emission of automobile exhaust.

REACTION ENGINEERING OF CHEMICAL PCBs DECHLORINATION: AN EXPERIMENTAL APPROACH

Abstract This paper deals with the application of some chemical reaction engineering principles in order to develop a supported liquid phase reagent (SLPR) able to dechlorinate PCBs contained in highly viscous media. The reagent consists of polyethyleneglycols containing a dissolved base and a radical initiator. Recently this mixture was proposed as CDP(R) (Chemical Dechlorination Process) for PCBs detoxification. In this paper are reported several experimental tests designed to optimise configuration of reagents on inert support to dechlorinate the PCBs contained in the transformer oil. The main results are: the evaluation of optimum reagent load on support, the set up of dechlorination kinetics of commercial PCBs as AROCLOR 1260 in transformer oil tested in the 50-2500 ppm range. SLPR was tested in a “fixed-bed” as well as in “slurry” reactor configurations. The above results were used to design two mobile plants for on-site treatments.

High Resolution PCB Analysis of Kanechlor, Phenoclor and Sovol Mixtures Using Multidimensional Gas Chromatography

Abstract Kanechlor-300, -400, -500 and -600, Phenoclor DP-3, -4, -5 and -6 and Sovol mixtures were analyzed for their chlorobiphenyl (CB) composition using high-resolution one-dimensional and multidimensional gas chromatography-electron capture detection (MDGC-ECD) techniques. The congener patterns of tested Kanechlor and Phenoclor mixtures resembled Aroclor 1016, 1242, 1254 and 1260. However, differences in the percentage contribution of minor constituents were noticed among these mixtures, which could be due to variations in the boiling-point fractionation of these commercial products. CB pattern of Sovol was different from the rest of the mixtures tested. It showed a composition in between ca. 30%, 40%, 50% and 60% overall chlorine levels. MDGC-ECD study showed the presence of hitherto unnoticed non-CB compounds coeluting with CBs in some commercial PCBs. The use of these mixtures as quantitation standards should be considered with caution. CB patterns of Sovol and a water extract of the Gulf of Finlan...

Interactions of 2,3,7,8-TCDD and PCB mixtures/congeners: Immunotoxicity studies

Several commercial PCBs, including Aroclors 1260, 1254, 1248, 1242 and 1232, were immunotoxic in C57BL/6 mice, however the results showed that the lower chlorinated biphenyls (Aroclor 1232 and 1242) were less toxic than the higher chlorinated mixtures. Treatment of C57BL/6J mice with an immunotoxic dose of 2,3,7,8-TCDD (3.7 nmol/kg) and a dose (25 mg/kg) of the commercial PCBs which was not immunotoxic showed that the PCB mixtures antagonized the 2,3,7,8-TCDD-mediated decrease in the plaque-forming cell response to sheep erythrocytes. The structure-dependent effects of individual PCB congeners to act as 2,3,7,8-TCDD antagonists were also investigated and only 2 compounds, namely 2,2′,4,4′,5,5′-and 2,3,3′,4,5,5′-hexachlorobiphenyl exhibited antagonist activity comparable to that observed for Aroclor 1254 as a 2,3,7,8-TCDD antagonist. The implications of these results will be discussed.

Toxic potential of non-ortho and mono-ortho coplanar PCBs in commercial PCB preparations: "2,3,7,8-T4 CDD toxicity equivalence factors approach.

Identification of highly toxic polychlorinated dibenzofurans (PCDFs) in commercial PCBs has contributed to the belief that they play a major role in the PCB toxicity. However, Quantitative Structure Activity Relationship (QSAR) studies have indicated that PCB congeners with chlorine substitution at both para and two or more meta positions resemble 2,3,7,8-tetrachlorodibenzo-p-dioxin (T/sub 4/CDD) in their biologic and toxic effects due to their coplanarity. The relative toxic potential of these PCB isomers in wild animals such as Forster's tern, marine mammals and Snapping turtle has been emphasized. Some members of these toxic congeners were also identified and quantitated in commercial PCBs. However, there is no serious effort to evaluate the toxic potential of these PCB congeners in commercial PCB mixtures. Hence an isomer-specific toxic evaluation was attempted in those mixtures to understand the chemical factors behind their toxicity.

Dibenzofurans a greater global pollutant than dioxins ?: Evidence from analyses of open ocean killer whale

Three specimens of killer whales ( Orcinus orca), an open ocean carnivore, were analysed for extremely toxic polychlorinated dibenzo- p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) to understand their long-range distribution patterns. Several PCDF congeners, including the highly toxic 2,3,7,8-tetra- and 2,3,4,7,8-penta-CDFs were identified in the blubber of those specimens. The PCDF isomeric pattern in killer whale is more complex than the reported patterns in humans and birds, indicating the weaker metabolic potency of killer whales for these toxic compounds. High levels of PCBs (about 400 mg kg −1) have also been detected in those specimens. The 2,3,7,8-substituted PCDF congeners identified in commercial PCBs were also found in killer whale, indicating PCBs as the possible source. Isomer-specific and trace level determinations of PCDD in killer whale, revealed no detectable quantities. The detection of comparatively high levels ( > 300 ng kg −1) of PCDFs and undetection of PCDDs in open ocean killer whales suggest that PCDFs are more ubiquitous than PCDDs.

Occurrence and distribution of toxic coplanar PCBs in the biota

The most toxic PCB congeners, namely, 3,3′,4,4′-tetra, 3,3′,4,4′,5-penta, and 3,3′,4,4′,5,5′-hexachlorobiphenyl (coplanar PCBs) were detected at ppb and higher ppt levels in humans and wildlife. The source of this toxic contamination was found to be commercial PCBs. Coplanar PCBs were detected at higher concentrations than 2,3,7,8-tetrachlorodibenzo- p-dioxin in humans and wildlife and may pose a greater toxic threat than dioxins and furans.

Selective detection of brominated aromatic compounds using gas chromatography/negative chemical ionization mass spectrometry

High-resolution gas chromatography/negative chemical ionization mass spectrometry (HRGC/NCI-MS, CH/sub 4/ reagent gas) was used for the selective detection of brominated and brominated/chlorinated aromatic compounds (benzenes, biphenyls, dibenzodioxins, dibenzofurans, diphenyl ethers, benzofurans, phenols) by monitoring characteristic bromide anions (Br/sup -/, m/z 79 and 81) formed under NCI conditions. High sensitivity (0.1 pg or better) with an acceptable linear range (up to several hundred picograms) and high selectivity with little interference from chlorinated analogues were observed. A structural requirement for high sensitivity was the presence of at least two Br substituents in a molecule, or a single Br with additional Cl substituents present. NCI mass spectra of the brominated and the brominated/chlorinated compounds investigated showed intense, often dominating Br/sup -/ ions. Application of HRGC/NRI-MS is documented with the analysis and detection of bromopolychlorobiphenyls (bromo-PCMs) in commercial PCBs, of brominated aromatic compounds in automotive emissions (exhaust), and of brominated dibenzofurans (PBDFs) in soot from an accidental fire.

Comparative aryl hydrocarbon hydroxylase induction activities of commercial PCBs in Wistar rats and rat hepatoma H-4-II E cells in culture

The activities of several commercial PCB mixtures as inducers of microsomal aryl hydroarbon hydroxylase (AHH) and ethoxyresorufin 0-deethylase (EROD) in male Wistar rats and rat hepatoma cells were dependent on the chlorine content (and congener distribution) of the mixtures. The was a correlation between the in vivo and in vitro induction potencies of these mixtures; the most active mixtures, Aroclors 1242, 1248 and 1254 contained 42–54% by weight of Cl whereas formulations with higher or lower (Aroclors 1221 and 1268 respectively) chlorine content exhibited lower activities. This corresponds with studies reported for PCB isomers and congeners in which the most active compounds are tetra-hexachlorobiphenyls.

Enhancement of PCBs biodegradation by sodium ligninsulfonate

Various mixtures of commercial PCBs (Aroclors) were rapidly biodegraded by Pseudomonas sp. 7509. The rate of biodegradation could be greatly enhanced by growing the cells in a stable PCB-ligninsulfonate emulsion. Microscopic examinations and growth studies suggested that biodegradation mainly took place at the PCB-water interface; the use of ligninsulfonate in the growth medium apparently allowed the cells to overcome the substrate limiting factor of surface area which, otherwise, might govern the subsequent rate of PCB degradation. Sodium ligninsulfonate was not degraded significantly in the PCB biodegradation process. Analyses of the culture broth, by gas chromatography, revealed that P. sp. 7509 could degrade 300 ppm of Aroclor 1254 after 18 days incubation. This degradation rate could be further enhanced by the addition of a small amount of Aroclor 1221 to the growth medium. A kinetic study, using resting cells, indicated that Aroclor 1221 was degraded much faster (980 μg h−1 mg cell dry wt−1) than the higher chlorinated Aroclor 1254 (43 μg h−1 mg cell dry wt−1). This finding was supported by manometric data which showed that regardless of the type of PCBs mixture used to grow the cells, the lower chlorinated PCBs were always oxidized faster than the higher chlorinated PCBs. The level of chlorination in a PCBs mixture therefore appears to be one of the major factors in determining its relative persistence to biodegradation.

The Finiding of Polychlorodibenzofurans in Commercial PCBs (Aroclor, Phenoclor and Clophen)

According to the modified methods of Vos and Poter et al., polychlorodibenzofurans (PCDFs) were separated and cleaned-up from commercial PCBs (Aroclor, Phenoclor and Clophen) which had been used in large quantities in the world. PCDFs were identified by gas chromatography-mass spectrometry and quantified by gas chromatography. PCDFs were found in all samples and the results were as follows.Aroclor: Tri to heptachlorodibenzofurans were found, and the total PCDF concentrations were 2-9ppm.Phenoclor: Tri to heptachlorodibenzofurans were found, and the total PCDF concentrations were 8-13ppm.Clophen: Di to hexaclorodibenzofurans were found, and the total PCDF concentrations were 5-17ppm.

Separation and Detection of Polychlorodibenzofurans (PCDFs) on Japanese Commercial PCBs (Kanechlors) and Their Heated Preparation

Modified analytical methods by Vos and Poter et al. were used for the separation of polychlorodibenzofurans (PCDFs) from Japanese commercial PCBs (Kanechlors) which were used in large quantities in Japan. Di, tri, tetra, penta, hexa and heptachlorodibenzofurans were detected on Kanechlors by GC-MS analysis. Total PCDF concentrations were 9, 33, 4 and 4ppm in Kanechlor 300 (KC-300), Kanechlor 400 (KC-400), Kanechlor 500 (KC-500) and Kanechlor 600 (KC-600), respectively. In addition, to investigate the possibility that PCDFs were formed during the usage of PCB as heat transfer medium, KC-400 was put into a pyrexglass ample and heated on a gas chromatograph oven. However, PCDFs did not generate by heating for 15 days at 300°C.