Coplanar Polychlorinated Biphenyls Research Articles

Optimized method for the determination of 25 polychlorinated biphenyls in water samples using stir bar sorptive extraction followed by thermodesorption-gas chromatography/mass spectrometry

An optimized method using stir bar sorptive extraction (SBSE) for the determination of 25 polychlorinated biphenyls (PCBs) from water samples among them three of the most toxic coplanar PCBs (PCB 77, PCB 126 and PCB 169) was developed. Since the investigated PCBs comprise all steps of chlorination (from PCB 1 as monochlorobiphenyl to PCB 209 as decachlorobiphenyl) the results should be representative for the total class of the 209 PCB congeners. For 8 ml spiked water samples with 2 ml methanol addition and 2 h exposure time of stir bars recoveries between 28% (PCB 209) and 93% (PCB 1, PCB 52, PCB 77) were found. Detection limits between 0.05 ng/l and 0.15 ng/l were calculated for the combination of SBSE and thermodesorption-GC/MS. The procedure was applied to the investigation of groundwater and river water samples from the industrial region of Bitterfeld northern Leipzig, Germany.

Fluorescence-based assay with enzyme amplification on a micro-flow immunosensor chip for monitoring coplanar polychlorinated biphenyls

Detection of pollutants is of significant importance for environmental protection. However, conventional monitoring methods are often time-consuming, and require expensive equipments. Biosensors based on enzyme linked immunosorbent assay (ELISA) provide an alternative method to conventional ones. In this research, the reduction in the size of ELISA utilizing micro-chemical reaction is described in a micro-flow immunosensor chip. The immunosensor chips were fabricated by micro-electromechanical system (MEMS) technology. The quantitative determination of coplanar polychlorinated biphenyls (Co-PCBs) was performed by using a micro-flow immunosensor chip. Polystyrene beads were used as the solid substrate for the immobilization of Co-PCB antibody. The antibody-immobilized beads were introduced into the flow channel. As a competitive ELISA, sample solution mixed with horseradish peroxidase (HRP) conjugated antigen, and non-HRP conjugated antigen was allowed to react in the flow channel. After the antigen–antibody reaction, addition of phosphate buffer solution containing hydrogen peroxide and the fluorogenic substrate produced a fluorescent dye, which was monitored with the resulting change in the fluorescence intensity. By using our micro-flow immunosensor chip, it was possible to determine the sensing range of Co-PCB derivatives up to 0.1 ppt in 30 s. This immunosensor chip had a wide linear range for Co-PCB detection from 0.1 pg/ml to 1.0 μg/ml. The regression analysis provided the correlation coefficients of r = 0.982−0.964 with good reproducibility and precision. In a series of five measurements with immunosensor chips prepared with a new batch of antibody-immobilized polystyrene beads, a relative standard deviation of 21.3% was obtained. Our immunosensor chip design reported here has the potential to be implemented to several different detection methodologies for numerous analytes.

Isolation and characterization of a novel polychlorinated biphenyl-degrading bacterium, Paenibacillus sp. KBC101

The biphenyl-utilizing bacterial strain KBC101 has been newly isolated from soil. Biphenyl-grown cells of KBC101 efficiently degraded di- to nonachlorobiphenyls. The isolate was identified as Paenibacillus sp. with respect to its 16S rDNA sequence and fatty acid profiles, as well as various biological and physiological characteristics. In the case of highly chlorinated biphenyl (polychlorinated biphenyl; PCB) congeners, the degradation activities of this strain were superior to those of the previously reported strong PCB degrader, Rhodococcus sp. RHA1. Recalcitrant coplanar PCBs, such as 3,4,3',4'-CB, were also efficiently degraded by strain KBC101 cells. This is the first report of a representative of the genus Paenibacillus capable of degrading PCBs. In addition to growth on biphenyl, strain KBC101 could grow on dibenzofuran, xanthene, benzophenone, anthrone, phenanthrene, naphthalene, fluorene, fluoranthene, and chrysene as sole sources of carbon and energy. Paenibacillus sp. strain KBC101 presented heterogeneous degradation profiles toward various aromatic compounds.

Effect of Chlorophyllin-Chitosan on Excretion of Dioxins in a Healthy Man

We investigated the usefulness of chitosan and chlorophyllin-chitosan (chl-chitosan) administration for reduction of the body burden of environmental dioxins, including polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDDs/ Fs) and coplanar polychlorinated biphenyls (Co-PCBs), by examining the excretion levels in the feces and sebum of a healthy man. The volunteer ate the same three meals every day during the 40-d experiment, which was composed of five phases (I-V) of 8 d each. In phase I (days 1-8), the volunteer was given only the basal diet. In phases II-V, 0.2 g of chitosan, 0.6 g of chitosan, 0.2 g of chl-chitosan, and 0.6 g of chl-chitosan, respectively, were administered immediately after each meal. We measured daily the amount of dioxins occurring in the feces and sebum during the last 5 d of each phase. The total toxicity equivalency (TEQ) of the dioxin in phases I-V were 27, 26, 38, 36, and 67 pg/d in the feces and 20, 19, 16, 16, and 14 pg/d in the sebum, compared with 74 pg/d in the food. The excretion of dioxins in the feces was significantly increased in phases III, IV, and V, being 140% (p < 0.05), 135% (p < 0.05), and 249% (p < 0.01) of the control level (phase I). Although the dioxin in the sebum was slightly decreased in phase V as compared with the control level, the total amount of excreted dioxin in feces and sebum was increased significantly in phase V, being 174% of the control level, which is almost the same level as that in the food. This indicates that chl-chitosan can prevent accumulation of dioxin, at least at the intake level of normal foods.

Effects of 2,2',4,4'-Tetrachlorobiphenyl on Granulocytic HL-60 Cell Function and Expression of Cyclooxygenase-2

Polychlorinated biphenyls (PCBs) are persistent environmental contaminants that affect a number of cellular systems, including neutrophils. It has been demonstrated that noncoplanar PCBs (i.e., ortho- substituted PCBs) alter function of primary rat neutrophils. The objectives of these experiments were to determine if responses in a human, neutrophil-like cell line exposed to PCBs were similar to those reported for rat neutrophils and to explore further PCB-mediated alterations in neutrophil function. The human promyelocytic leukemia cell line (HL-60) was differentiated with DMSO to a neutrophil-like phenotype. Treatment of differentiated HL-60 cells with 2,2',4,4'-tetrachlorobiphenyl, a noncoplanar, ortho-substituted PCB congener, caused an increase in f-Met-Leu-Phe-induced degranulation, as measured by release of myeloperoxidase (MPO). Treatment with the coplanar, non-ortho-substituted congener 3,3',4,4'-tetrachlorobiphenyl had no effect on MPO release. 2,2',4,4'-Tetrachlorobiphenyl caused a time- and dose-dependent release of [3H]-arachidonic acid (3H-AA). A significant increase in 3H-AA release was observed after 60 min of exposure, and concentrations of 10 microM or larger increased 3H-AA release. In contrast, 3,3',4,4'-tetrachlorobiphenyl had no effect on 3H-AA release. The effect of PCBs on mRNA levels for cyclooxygenase-2 (COX-2) was examined using semiquantitative RT-PCR. COX-2 mRNA was significantly elevated in response to 2,2',4,4'-tetrachlorobiphenyl in a concentration-dependent manner. COX-2 expression was maximal by 30 min of exposure to 2,2',4,4'-tetrachlorobiphenyl. COX-2 protein and activity were also increased after exposure to 2,2',4,4'-tetrachlorobiphenyl; COX-1 protein and activity were unaffected. 3,3',4,4'-Tetrachlorobiphenyl did not increase COX-2 mRNA levels. These results demonstrate that a noncoplanar PCB alters the functional status of granulocytic HL-60 cells, causing enhanced degranulation and upregulation of COX-2, whereas a coplanar PCB lacks this activity. These data suggest that noncoplanar PCBs alter HL-60 cell function and COX-2 expression via an Ah-receptor-independent mechanism.

Levels of Dioxins in Japanese Fruit in 1999 to 2002 and Estimation of Their Intake

A total of 148 samples of nine species of fruit were collected between 1999 and 2002 and analyzed for PCDDs, PCDFs (PCDD/Fs) and Coplanar PCBs. Sampling points within about 1 km of operational municipal waste incinerators that were considered sources of dioxins were defined as "near-source" areas, and all other sampling points were defined as "general" areas. The TEQ of apples collected from near-source areas was significantly higher than that from general areas (p < 0.05). 3,3',4,4',5-PeCB (#126) was the main contributor to this difference in TEQs between apples collected from near-source areas and from general area. A principal component analysis performed to estimate the source of this congener revealed that not only the municipal waste incinerators, but also PCBs in the environment were associated with the high TEQ in apples collected from near-source areas. The daily intakes of PCDD/Fs and Coplanar PCBs from the fruits including skin were estimated to be 0.0082 pg-TEQ/kg b.w./day (ND = 0) and 0.072 pg-TEQ/ kg b.w./day (ND = 1/2 LOQ). Though these values are likely to be overestimates, they are far lower than the tolerable daily intake set in Japan for PCDD/Fs and Coplanar PCBs (4 pg-TEQ/kg b.w./day). It is thought that fruit intake is not an important pathway of human exposure to PCDD/Fs and Coplanar PCBs.

Dioxin Concentrations in Body Tissues and Egg of Female Chicken

To investigate the transfer and accumulation of ingested dioxins, the concentra-tions of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar-polychlorinated biphenyls (Co-PCBs) in the muscle, abdominal fat, liver, and egg of hens (Dekalb TX-35) at 1, 58, 184, and 462 days of age were measured. The levels of these three components in the four diets-starting, early growing, late growing, and laying-fed to the experimental birds were also measured. Using gas chromatography-mass spectroscopy, the concentration of each isomer of PCDD, PCDF, and Co-PCB was measured. The concentration of each component was multiplied by the individual toxic equivalency factor (TEF), the values for the isomers of each dioxin component were added together, and a toxic equivalency quantity (TEQ) was derived for each component. The total dioxin concentration (sum of TEQs for PCDDs, PCDFs, and Co-PCBs) in the muscle rose 5-fold from 58 to 462 days of age due to an increase in the amount of ether extract from muscle. These dioxin values were within the range reported for domestic chicken meat (0.0007 to 0.265pg-TEQ/g). However concentrations in the abdominal fat and liver did not increase during the same period, suggesting that the liver is not a leading dioxin accumulation site for fowl. Dioxin concentrations in whole egg did not differ between 184 and 462 days of age and were within the reported range (0.009 to 0.138pg-TEQ/g). This finding suggests that most of the ingested and stored dioxin did not enter the egg during the early laying period.

Distribution of PCDDs/PCDFs and Co-PCBs in Human Maternal Blood, Cord Blood, Placenta, Milk, and Adipose Tissue: Dioxins Showing High Toxic Equivalency Factor Accumulate in the Placenta

To assess levels of dioxin background contamination and transfer of dioxins from mothers to unborn children and infants, concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar-polychlorinated biphenyls (Co-PCBs) were measured in human samples from expectant and nursing mothers living in Nara, Japan. The average toxic equivalency quantities (TEQs) of PCDDs/PCDFs and Co-PCBs from circulating maternal blood, cord blood, placenta, milk taken 3-10 d after delivery, milk taken one month after delivery, and adipose tissue were 26 and 9.3, 15 and 2.3, 31 and 1.2, 16 and 5.4, 18 and 8.8, and 16 and 7.7 pg-TEQ/g-fat, respectively. Among the various PCDD/PCDF congeners, 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF contributed most heavily to the TEQs of all maternal samples. Among the various Co-PCB congeners, 3,3',4,4',5-PeCB (#126), 2,3,3',4,4',5-HxCB (#156), and 2,3',4,4',5-PeCB (#118) contributed most heavily to the TEQs of all maternal samples. But, the concentrations and relative percentages of congeners differed among the various samples, suggesting that congeners showing high toxic equivalency factor accumulate in the placenta.

Loss of Polychlorinated Dibenzo-p-dioxins, Polychlorinated Dibenzofurans and Coplanar Polychlorinated Biphenyls during Vacuum Concentration for Ultra-trace Analysis

We investigated the effect of kinds of organic solvent on the losses of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DFs), coplanar polychlorinated biphenyls (Co-PCBs), and their 13C12-labeled compounds during vacuum concentration. n-Hexane and toluene solutions containing the standards of those compounds were tested for the purpose. The kind of organic solvent has remarkable effect on the loss of 13C12-Co-PCBs from the standard solutions, while it has little or no effect on the losses of Co-PCBs, PCDD/DFs, and 13C12-PCDD/DFs from the standard solutions. The losses of lower chlorinated 13C12-Co- PCBs with n-hexane solution were greater than the loss of the compounds with toluene solution. The relative amounts of 13C12-Co-PCBs in the condensate solvent produced during the vacuum concentration show that those of the compounds with toluene solution were less than that of n-hexane solution. These results demonstrate that the minimization of loss of the compounds with n-hexane solution may be achieved by adding toluene before the vacuum concentration. We also examined the relationship between the relative amounts of Co-PCBs and 13C12-Co-PCBs in the condensate solvents and vapor pressures of those compounds. There was the difference in the regression line slopes of the relative amounts vs. in the vapor pressures between the n-hexane solution and toluene solution. This fact could be useful for the optimization of the vacuum concentration conditions in the convenient analytical methods.

Contamination Levels of PCDDs, PCDFs and Co-PCBs in Commercial Baby Foods in Japan

To examine dioxin contamination in commercial baby foods in Japan, congener analyses of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) were performed on 102 varieties of baby foods obtained from supermarkets in 2001-2002. The toxic equivalent quantity (TEQ) levels for dioxins in samples ranged from < 0.001 to 0.135 pg-TEQ/g wet weight when undetected or trace levels of congeners were taken as zero. Among 102 samples tested, 26 samples exceeded 0.010 pg-TEQ/g. The highest TEQ value was for "sardine, vegetables" (0.135 pg-TEQ/g), followed by "Japanese radish (daikon), sardine" (0.080 pg-TEQ/g). Thus, dioxins were detected at low levels in baby foods containing animal products such as fishes and/or dairy products.

Contamination Levels of PCDDs, PCDFs and CoPCBs in Fish Oils Used as Raw Materials for Margarine and Shortening and Retailed Fish

Toxic equivalent (TEQ) levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs) and coplanar polychlorinated biphenyls (CoPCBs) were analyzed in both crude (n = 5) and refined-hardening fish oils (n = 2), which are used in part as the raw materials of margarine and shortening, and in some retailed fish (n = 6), which may be similar to those used as sources of fish oil. PCDDs/DFs-TEQ levels ranged from 0.1 to 13.5 pg TEQ/g fat weight in crude fish oils, from 0.5 to 1.6 pg TEQ/g fat weight in refined-hardening fish oils, and ranged from 1.4 to 31.2 pg TEQ/g fat weight in retailed fish. The ranges of PCDDs/DFs-TEQ in crude fish oils, in refined-hardening fish oils and in retailed fish overlapped each other. In addition, CoPCBs-TEQ levels ranged from 4.9 to 19.6 pg TEQ/g fat weight in crude fish oils, from 0.2 to 1.4 pg TEQ/g fat weight in refined-hardening fish oils, and from 2.7 to 165.8 pg TEQ/g fat weight in retailed fish. TEQ levels of CoPCBs in refined-hardening fish oils were much lower than those in crude fish oils and in retailed fish. This was due to the lower concentrations of less-chlorinated congeners in refined-hardening fish oils, as compared to those in crude fish oils and retailed fish. It appears that less-chlorinated PCBs congeners in refined-hardening fish oils are partly removed during the refining process.

Preparation and Certification of the Reference Materials, Marine Sediment for the Determination of Dioxins and Polychlorobiphenyls

The Japan Society for Analytical Chemistry has developed two new certified reference materials (CRMs) for dioxins: coplanar PCBs and 1 ~ 10 chlorinated PCB homologues. A project team has been organized to prepare 2 kinds of marine sediment and to certify the concentration of dioxins and polychlorobiphenyls. An interlaboratory comparison test was performed by participants from 24 laboratories. In a statistical analysis, the z scores in robust method were applied to reject outliers, followed by the usual statistical procedure. The presented CRMs are expected to be useful for the quality assurance and quality control of dioxins analysis.

Effects of PCBs 52 and 77 on Th1/Th2 Balance in Mouse Thymocyte Cell Cultures

Polychlorinated biphenyls (PCBs) are industrial chemicals that have been released into the environment, resulting in widespread and persistent contamination. PCBs exist as 209 different congeners depending on the chlorine substitution on the biphenyl rings, and the physical properties and toxic effects of different PCB congeners are structure-dependent. We have tested an ortho-substituted, noncoplanar congener, 2,2′,5,5′-tetrachlorobiphenyl (PCB 52), and a non-ortho-substituted coplanar congener, 3,3′,4,4′-tetrachlorobiphenyl (PCB 77), for their effects on the T helper 1 (Th1) and T helper 2 (Th2) lymphocyte balance. The experiments were performed in 10 μg/ml concanavalin A (Con A)-stimulated and nonstimulated thymocytes for determination of cytokine production profiles. Interferon-γ (produced by Th1 cells) and interleukin (IL)-10 (produced by Th2 cells) concentrations were measured in the supernatants at 12 and 24 hr after treatment with PCBs. PCBs 52 and 77 caused significant increases in interferon-γ levels at 12 and 24 hr in both Con A-stimulated and nonstimulated media. IL-10 levels were significantly reduced at two interval periods by PCBs 52 and 77 in cultures with and without Con A. Our results show that the cytokine production profile was significantly shifted to Th1 by both ortho-substituted and coplanar PCB congeners in mouse thymocyte cultures

COMPARATIVE METABOLISM OF POLYCHLORINATED BIPHENYLS AND TISSUE DISTRIBUTION OF PERSISTENT METABOLITES IN RATS, HAMSTERS, AND GUINEA PIGS

The present study was performed to compare the metabolite profiles of polychlorinated biphenyls (PCBs) in the liver and serum of rats, hamsters, and guinea pigs after exposure to a PCB mixture, Kanechlor 500 (100 mg/kg, i.p.). The percentage of contribution of major PCB residues in the liver 5 days after exposure indicated that nonplanar PCBs with 2,4- or 2,3,4-chlorine substitution were more abundant in the liver in the order rats (43% of total PCBs) > hamsters (20%) > guinea pigs (11%), whereas coplanar PCBs with 4-, 3,4-, or 3,4,5-chlorine substitution were predominant in guinea pigs (61%), followed by hamsters and rats (both 26%). The hepatic concentrations of methylsulfonyl metabolites (MeSO(2)-CBs) were higher in the order guinea pigs > rats > hamsters. Whereas hamsters formed minute amounts of MeSO(2)-CBs from 2,5-dichloro-substituted PCBs, guinea pigs formed higher levels of meta-MeSO(2)-CBs derived from 2,3,6-trichloro-substituted PCBs. In contrast, the serum concentrations of phenolic PCBs were higher in the order hamsters > rats > guinea pigs. Metabolites were predominated by 4-OH-2,3,5,3',4'-pentaCB (89% contribution) for rats, 3-OH-2,4,5,2',4'-pentaCB (56%) for guinea pigs, and dihydroxylated metabolites (39%) for hamsters. The reduced elimination of coplanar PCBs and the specific distribution of MeSO(2)- and phenolic PCBs may have implications for the differences in sensitivity to PCB toxicity among rats, guinea pigs, and hamsters.

Lineage-specific effects of polychlorinated biphenyls (PCB) on gene expression in the rabbit blastocyst

The ubiquitous toxic environmental contaminants polychlorinated biphenyls (PCBs) change gene expression in preimplantation embryos. Cell lineage-specific effects of PCB are not known. Rabbit day 6 blastocysts were exposed in vitro to low (0.1 ng/congener/mL medium) and high (1 μg) PCB levels of coplanar (PCB 77, 126, and 169) or non-coplanar PCBs (PCB 28, 52, 101, 118, 138, 153, and 180). Embryoblast (ICM) and trophoblast cells (TE) were separated and analyzed for transcriptional changes of PCB-and implantation-associated genes by semiquantitative RT-PCR. PCBs increased CYP 1A1 mRNA only in the ICM. CYP 1B1, VEGFR2, and COX-2 transcript numbers were elevated in both ICM and TE. Transcripts for HIF-1α were decreased in the ICM. No obvious differences in gene expression following exposure to coplanar and non-coplanar PCBs were detected. Our results show that transcriptional responses to PCBs differ between the cell lineages of the rabbit blastocyst, indicating that PCBs can influence the highly sensitive process of early mammalian development.

Biomonitoring of persistent organochlorine pesticides, PCDD/PCDFs and dioxin-like PCBs in blood of children from South West Germany (Baden-Wuerttemberg) from 1993 to 2003

In the context of a monitoring program, persistent organic pollutants (POPs) were quantified in the blood of 10 year old children at four different demographic regions in Baden-Wuerttemberg, a highly industrialised federal state in South West Germany. DDE, HCB, PCB 138, PCB 153 and PCB 180 were measured in 1996/1997, 1998/1999, 2000/2001 and 2002/2003 in individual samples of about 400 children per year. PCDD/PCDFs and some relevant coplanar PCBs were determined in pooled samples from children in seven cycles from 1993 to 2003. Blood concentrations of the investigated compounds decreased in that time period by a factor of 2–4 with the exception of most PCDFs. The concentrations of POPs in the blood of the children were distinctly lower than the concentrations reported for adults. Breast feeding was associated with about 30% higher median concentrations of DDE, HCB, PCBs and a 30% increase for mean PCDD/PCDF concentrations. Concerning demographic differences, significant lower concentrations of HCB, PCBs and PCDD/PCDFs could be seen in children from Mannheim compared to the region of Aulendorf. About 10–20% higher concentrations were found in boys compared to girls for HCB, indicator PCBs and PCDD/PCDFs. The pattern of non-ortho and mono-ortho PCBs in the blood of children was similar to the pattern reported for mother’s milk, and PCB 126 and PCB 156 contributed about 70% to the toxicity of dioxin-like PCBs and about one-third to total TEQ including PCDD/PCDFs.

The role of metals in dioxin formation from combustion of newspapers and polyvinyl chloride in an incinerator

Newspapers impregnated with NaCl mixed with various chloride metals (CuCl 2, MgCl 2, MnCl 2, FeCl 3, NiCl 2, and CoCl 2) and electric wire coated with polyvinyl chloride (PVC) were combusted in a well-controlled incinerator. Exhaust gas samples collected at the outlet of the incinerator were analyzed for dioxins (PCDDs, PCDFs, and coplanar PCBs) by gas chromatography/mass spectrometry. The amount of total dioxins formed from newspaper samples ranged from 34.2 ng/g (with NaCl + CoCl 2) to 67.0 ng/g (with NaCl + CuCl 2). PCDFs composed 88–94% of the total dioxins formed in the exhaust gases. The highest levels of PCDF isomers obtained were Cl 3-CDF from the sample with NaCl + CuCl 2 (14.8 ng/g), Cl 2-CDF from the sample with NaCl + MgCl 2 (12.3 ng/g), and Cl 1-CDF from samples with NaCl + MnCl 2 (12.6 ng/g), with NaCl + FeCl 3 (11.8 ng/g), and with NaCl + NiCl 2 (13.3 ng/g), and with NaCl + CoCl 2 (8.62 ng/g). The total of Cl 4–8-CDDs comprised 76–88% of the total Cl 1–8-CDDs. In particular, Cl 7-CDDs had the highest levels except for the sample with NaCl + NiCl 2. Total dioxins formed from samples of electric wire coated with PVC and PVC alone were 38.3 ng/g and 112 ng/g, respectively, suggesting that the presence of copper reduced dioxin formation.

Polychlorinated dibenzo- p-dioxins, -dibenzofurans, and biphenyls in domestic animal food stuff and their fat

Concentrations of polychlorinated dibenzo- p-dioxins (PCDDs), dibenzo- p-dioxins (PCDFs) and dioxin-like coplanar PCBs and 2,3,7,8-tetrachlorodibenzo- p-dioxin equivalents (TEQs) were measured in domestic animal related samples such as feed ingredient, mixed feed and animal fat from Japan. The mean concentration of total PCDDs, PCDFs and coplanar PCBs in fish oil was 17 000 pg g −1 lipid wt, which 9- to 30-fold greater than that from other animal originated ingredients. Mixed feed for chicken and chicken fat contained greater total PCDDs, PCDFs, coplanar PCBs concentrations (190 and 2100 pg g −1 lipid wt) compared to those for pig (120 and 320 pg g −1 lipid wt). WHO-TEQs were ranged 0.39–13, 0.15–0.22 and 0.73–2.8 pg g −1 lipid wt for ingredients, mixed feeds and animal fats, respectively. Greater biomagnification factor was noticed for congeners 1,2,3,7,8-PeCDD, 1,2,3,6,7,8-HxCDD, 2,3,7,8-TCDF and 1,2,3,4,7,8-HxCDF in chicken and pig fat. Biomagnification factors for both mono- and non- ortho coplanar PCBs were greater in chicken fat compared to those in pig fat.

Atmospheric Deposition and Fluxes of Organochlorine Pesticides and Coplanar Polychlorinated Biphenyls in Aquatic Environments of Hong Kong, China

Concentrations of organochlorine (OC) pesticides and coplanar (dioxin-like) polychlorinated biphenyls (PCBs) in bulk deposition were measured at the Mai Po Marshes Nature Reserve (MPMNR) and A Chau, which are both important habitats for waterbirds in Hong Kong. OC pesticides exempted from the Stockholm Convention were present in greater concentrations than those that have been restricted for use in the region. Among the OC pesticides, HCB, sigmaDDTs, and sigmaHCHs were detected. Concentrations of HCB were greater at MPMNR than at A Chau, and this finding suggests short-range transport of this compound, which is different from the other OC pesticides. Several environmental factors including seasonal variations in temperature, particulate matter, and rainfall may influence the flux of OC pesticides. Since sources of HCB often coexist with sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (dioxins and furans), the presence of HCB may be a useful surrogate for monitoring airborne dioxins and for understanding their deposition potential. The contribution of atmospheric deposition to the OC pesticide input to the two study sites was small. Concentrations of most OC pesticides in surface waters were greater than would be predicted based on the inputs from atmospheric deposition and sedimentation. The mass balance calculation suggests a net flux of OC pesticides from bottom sediments to the overlying water column.

Excretion pattern of co-planar and non-planar tetra- and hexa-chlorobiphenyls in ovine milk and faeces

This study employed the gas chromatography with electron capture detection to determine residual levels and excretion patterns of two pairs of structurally diverse polychlorinated biphenyl (PCB) congeners (IUPAC Nos. 54, 80, 155, and 169) administered to lactating sheep by intramuscular injection. PCB levels and excretion patterns in blood, milk, and faeces were time-dependent and differed from the composition of PCB congeners administered. Lactational transfer substantially exceeded the faecal transfer. Between days 3 and 7, the amount of PCB congeners 54 and 169 excreted in milk was around 50- and 800-fold higher than the amount of these two congeners excreted via faeces. During the same period, the relative contribution of co-planar PCB congeners (80 and 169) in PCB pattern decreased in blood and increased in milk and faeces compared with non-planar PCBs (54 and 155). On day 3, the ratio PCB 169 to 54 was 7-fold higher in milk than in faeces. PCB congeners with log K ow values under 6.5 reached peaks of their excretion in milk within the first three days after administration, while the super-lipophilic PCB 169 congener with log K ow value of over 7 has not reached the plateau until day 10, but afterwards, its level remained relatively high throughout the observation period. During the 57-day follow-up period, the excretion of PCB 80, 155, and 169 in milk was 4.5-, 14-, and 46-fold greater compared with PCB 54. Differences in levels and patterns were explained with some physico-chemical properties of individual PCB congeners, such as lipophilicity, planarity, metabolic stability, sorption/diffusion properties.