Technical Mixture Of Polychlorinated Biphenyls Research Articles

Sources of polychlorinated biphenyls (PCBs) in sediments of the East China marginal seas: Role of unintentionally-produced PCBs

The production and use of intentionally-produced polychlorinated biphenyls (PCBs) in China have a short history compared with countries of North America and Europe, where technical PCB mixtures were manufactured in large amounts for decades before being banned. Unintentionally-produced PCB emissions increased dramatically in China, leading to unique profiles of PCB burdens. This study first time evaluated 208 individual PCB congeners at 94 sites from surface sediments of the East China Marginal Seas (ECMSs) and explored their sources. Non-technical PCBs transported from atmospheric transport and river discharge played a dominant role in most areas of the ECMSs, while historical residuals of technical PCBs occupied the fine-grained sediments in muddy areas of the central Yellow Sea (YS), regarding to the low sedimentation rate in the central YS. Furthermore, emissions from Taizhou located on the coast of the East China Sea (ECS), which is an important electronic waste dismantling site in East China, contributed additional technical PCBs to the inner shelf of the ECS. Our results indicate that non-technical PCBs have become the dominant PCB species in the ECMSs, and emphasize the synergistic effects of large riverine input, long-range atmospheric transport, and muddy shelf deposition on PCB source and sink of in marginal seas.

Distribution, Sources and Risk Assessment of Polychlorinated Biphenyls in Sediments from Beiluo River.

The distribution and source of polychlorinated biphenyls (PCBs) pollution in the Beiluo River, the secondary tributary of the Yellow River, still remain unclear. With the purpose of determining the distribution, origins, and pollution levels of PCBs and their consequences on ecological risks, the concentrations of 27 PCBs at 17 locations in the sediments of the Beiluo River were examined in this study. The results showed that the mass concentrations of ∑PCBs in the sediment ranged from 0.12 to 1.25 ng∙g-1 (DW), with the highest point at sampling site B13 downstream of the river. Compared to most river sediments, both domestically and internationally, the concentration of PCBs in the sediment of the Beiluo River was at a low level, with 10-PCB and 6-PCB as the main components, indicating that the PCBs that are difficult to volatilise and degrade are more likely to remain in the sediment. The origins of PCBs in the sediments of the Beiluo River were examined by using positive matrix factorisation (PMF). The results revealed that the contamination of PCBs in the sediments of the Beiluo River mainly resulted from industrial emissions, technical PCB mixtures, and coal and wood combustion. The results of the ecological risk assessment indicated that PCBs in the sediments of the study area rarely contribute to adverse biological effects and the potential low risk to the environment.

Occurrence, Potential Risk Assessment, and Source Apportionment of Polychlorinated Biphenyls in Water from Beiluo River

Polychlorinated biphenyls (PCBs) are highly hazardous, persistent, and bioaccumulative substances that pose a threat to water quality in a number of locations, including the Beiluo River in Shaanxi Province, China. However, little is known about the contribution of PCBs to the Beiluo River. In this study, in order to look into the impact of sources on the water of the Beiluo River, the discovered PCB congeners in water were examined on a regional scale. The concentration of PCBs in water across Beiluo River was in the range from 0.065 to 1.92 ng L−1, and the average concentration was 0.37 ng L−1. The main PCB sources in the Beiluo River waterbody were found using positive matrix factorization (PMF). Source apportionment results indicated that the PCB pollution of the Beiluo River was mostly caused by industrial emissions, technical PCB mixtures, and coal and wood combustion. According to current ecological risk assessment guidelines, the PCB concentrations found in this study may have a negative impact on biological systems. Overall, the new information about the presence of several PCBs in the water of the Beiluo River justifies the need for urgent management actions, as well as long-term monitoring efforts, to protect ecosystems. Future investigations of these chemicals in China may use the conclusions of this first ecological risk level assessment on the PCB contamination in the waterbody of the Beiluo River as a guide.

Comprehensive determination of polychlorinated biphenyls and brominated flame retardants in surface sediment samples from Hanoi urban area, Vietnam: Contamination status, accumulation profiles, and potential ecological risks

Comprehensive and updated information about polychlorinated biphenyls (PCBs) and brominated flame retardants (BFRs) in surface sediments from Hanoi, the capital city of Vietnam, is rather scarce. In this study, concentrations and profiles of 209 PCBs, 41 polybrominated diphenyl ethers (PBDEs), 2,2′,4,4′,5,5′-hexabromobiphenyl (BB-153), hexabromocyclododecane (HBCD), pentabromoethylbenzene (PBEB), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), and decabromodiphenyl ethane (DBDPE) were determined in sediment samples collected from the Red River and some inner-city rivers of Hanoi. Concentrations (ng/g dry weight, median and range) of pollutants decreased in the order: DBDPE (28; not detected ND – 59) ≈ PCBs (27; 1.7–50) > PBDEs (23; 0.20–61) > HBCD (1.2; ND – 5.2) > BTBPE (0.46; ND – 3.6) > BB-153 (0.004; ND – 0.014) > PBEB (ND). Pollutant levels in the inner-city river sediments were about one to two orders of magnitude higher than those measured in the Red River main stream sediments. Tri-to hexa-CBs are major homologs but detailed profiles vary between individual samples, reflecting source and/or seasonal variations. CB-11 and CB-209 were found at higher proportions in sediments than in technical PCB mixtures, suggesting their novel sources from pigments. Deca-BDE and DBDPE are the most predominant BFRs with an increasing trend predicted for DBDPE. A preliminary ecological risk assessment was conducted for these pollutants in sediments. Total PCBs and deca-BDE in a few inner-city river sediments may exhibit adverse effects on benthic organisms, but no serious risk was estimated in general.

Comprehensive Monitoring of More Than 1000 Organic Micro-pollutants in Drainage Water: Case Study in a Rural Village with End-of-Life Vehicle Processing Activities in Northern Vietnam

A comprehensive and detailed monitoring scheme was applied to examine more than 1000 organic micro-pollutants (OMPs) in drainage water samples collected from a rural village with informal end-of-life vehicle processing activities in northern Vietnam. Concentrations of total OMPs ranged from 8900 to 34,100 (median 11,400) ng L−1. In our water samples, major classes of organic pollutants were n-alkanes, squalane, synthetic phenolic antioxidants and derivatives (SPAs), and polycyclic aromatic hydrocarbons (PAHs), which together accounted for 97% in average of total OMPs. Trace levels of polychlorinated biphenyls (PCBs) and brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and decabromodiphenyl ethane (DBDPE) were also detected. In particular, CB-11 (3,3′-dichlorobiphenyl), which is a minor component of technical PCB mixtures but is a dominant impurity in many organic pigments, was found in all the samples (median 0.20; range 0.14–0.23 ng L−1; accounting for 5% in average of total PCBs). In general, concentrations of almost all the OMPs investigated in this study were lower than critical values for any ecotoxicological risk.

Contamination Status and Emission Sources of Polychlorinated Biphenyls in Settled Dust from End-of-life Vehicle Processing and Urban Areas, Northern Vietnam

Concentrations of polychlorinated biphenyls (PCBs) including 43 congeners of 10 homologs were determined in settled dust samples collected from urban houses and end-of-life vehicle (ELV) processing workshops in northern Vietnam. Concentrations of total 43 PCBs (ΣPCBs), 7 indicator PCBs (IN-PCBs), and 12 dioxin-like PCBs (DL-PCBs) in the ELV workshop dusts were significantly higher than those measured in the urban house dusts, suggesting ELV processing activities as potential sources of PCBs. However, concentrations of PCB-11 (3,3’-dichlorobiphenyl) in the urban house dusts (mean 4.5; range 1.2–8.7 ng/g) were markedly higher than levels found in the ELV workshop dusts (1.6; 0.46–5.4 ng/g). PCB-11 is a novel congener because it is only a trace component of technical PCB mixtures but identified as a major impurity of many organic pigments, especially diarylide yellow pigments. PCB patterns of the ELV workshop dusts were dominated by penta- and hexa-PCBs with major congeners as PCB-118, -138, -153, -110, and -101, which were also principal components of technical formulations such as Aroclor 1254, Kanechlor 500, and Sovol. Meanwhile, PCB-11 served as the most predominant congener detected in the urban house dusts, implying current emissions from paints and pigmented products; however, this point should be confirmed by further studies on the occurrence of PCBs in Vietnamese commercial products. Apart from PCB-11, the urban house dusts also contained elevated proportions of penta- and hexa-PCBs, suggesting residues from electrical equipment application in the past. Our results indicate that even though PCBs are legacy and banned chemicals, their presence has been observed in indoor environments due to their persistent nature and novel emission sources. Further studies on the occurrence and emission behavior of these pollutants should be conducted, including not only congeners in technical mixtures but also unintentionally produced compounds.

Effect of Microplastic Amendment to Food on Diet Assimilation Efficiencies of PCBs by Fish.

Diet assimilation efficiencies (AEs) of polychlorinated biphenyls (PCBs) absorbed to microplastics and food were determined in goldfish ( Carassius auratus). Microplastics were spiked with 14 environmentally rare PCBs and incorporated into fish pellets previously spiked with a technical PCB mixture (Aroclor 1254). Five diet treatments were created having microplastic contents of 0, 5, 10, 15, 20, and 25% and fed to fish within 24 h of the diet creation. Fish from each treatment were fed a microplastic amended food pellet and PCB AEs were determined by mass balance. Microplastic-associated PCBs had lower AEs (geomean 13.36%) compared to food matrix-associated PCBs (geomean 51.64%). There were interactions between PCB AEs and the microplastic content of the diet. PCBs affiliated with microplastics became more bioavailable with increasing microplastic content of food while food matrix-associated PCB bioavailability declined when microplastic contents exceeded 5%. Despite controlling for microplastic-food contact time, there was some evidence for redistribution of lower KOW food matrix-associated PCBs onto microplastics causing a decrease in their AE relative to nonplastic and low plastic containing diets. The low bioavailability of microplastic-associated PCBs observed in the present study provides further support to indicate that microplastics are unlikely to increase POPs bioaccumulation by fish in aquatic systems.

Polychlorinated Biphenyls in Surface Soil from North-East India: Implication for Sources Apportionment and Health-Risk Assessment.

Although India never manufactured polychlorinated biphenyls (PCBs), evidence suggests the prevalence of PCBs in multi-environmental matrices. Despite the high level of PCBs that has been detailed in the major urban areas of India, little is known about the fate and sources of PCBs in Northeast India (NEI). This motivated us to investigate the contamination level and sources of PCBs in the surface soil. In this study, the environmental concentration and sources of 25 PCBs were investigated in surface soil (n = 60) from three states of NEI (lower Assam, Manipur, and Tripura). Additionally, the relationship between soil organic carbon (SOC) and PCBs was studied to investigate the role of SOC in the distribution of PCBs. Overall, the concentration of ∑25PCBs ranged from 2950 to 16,700pg/g dw (median 7080pg/g dw), 3580-21,100pg/g dw (median 11,500pg/g dw), and 2040-11,000pg/g dw (median 4270pg/g dw) in Assam, Manipur, and Tripura, respectively. Low-chlorinated PCBs were more prevalent than highly chlorinated PCBs. PCB-49 was identified as the most abundant in soil, followed by PCB-52, and accounted for 13% and 12.9% of ∑25PCBs, respectively. With respect to land use categories, high ∑25PCBs were related to grassland areas and proximity to the roadside soil. The principal component analysis indicated emissions from technical PCB mixtures, combustion of municipal wastes/residential wood, incineration of hospital wastes, and e-waste recycling/disposal sites are the real sources of PCBs. Marginally, a moderate-to-weak correlation of SOC with ∑25PCBs (R2 = 0.144, p < 0.05) and their homologs (R2 = 0.280-0.365, p < 0.05) indicated the little role of SOC in the dispersion of PCBs. The estimated toxic equivalency of dioxin-like PCBs suggested that PCB-126 is the most toxic contaminant to endanger the human population.

Spatial and seasonal variations, sources, air-soil exchange, and carcinogenic risk assessment for PAHs and PCBs in air and soil of Kutahya, Turkey, the province of thermal power plants.

Atmospheric and concurrent soil samples were collected during winter and summer of 2014 at 41 sites in Kutahya, Turkey to investigate spatial and seasonal variations, sources, air-soil exchange, and associated carcinogenic risks of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). The highest atmospheric and soil concentrations were observed near power plants and residential areas, and the wintertime concentrations were generally higher than ones measured in summer. Spatial distribution of measured ambient concentrations and results of the factor analysis showed that the major contributing PAH sources in Kutahya region were the coal combustion for power generation and residential heating (48.9%), and diesel and gasoline exhaust emissions (47.3%) while the major PCB sources were the coal (thermal power plants and residential heating) and wood combustion (residential heating) (45.4%), and evaporative emissions from previously used technical PCB mixtures (34.7%). Results of fugacity fraction calculations indicated that the soil and atmosphere were not in equilibrium for most of the PAHs (88.0% in winter, 87.4% in summer) and PCBs (76.8% in winter, 83.8% in summer). For PAHs, deposition to the soil was the dominant mechanism in winter while in summer volatilization was equally important. For PCBs, volatilization dominated in summer while deposition was higher in winter. Cancer risks associated with inhalation and accidental soil ingestion of soil were also estimated. Generally, the estimated carcinogenic risks were below the acceptable risk level of 10-6. The percentage of the population exceeding the acceptable risk level ranged from <1% to 16%, except, 32% of the inhalation risk levels due to PAH exposure in winter at urban/industrial sites were >10-6.

Formation of Polychlorinated Biphenyls on Secondary Copper Production Fly Ash: Mechanistic Aspects and Correlation to Other Persistent Organic Pollutants.

Emission of unintentionally formed polychlorinated biphenyls (PCBs) from industrial thermal processes is a global issue. Because the production and use of technical PCB mixtures has been banned, industrial thermal processes have become increasingly important sources of PCBs. Among these processes, secondary copper smelting is an important PCB source in China. In the present study, the potential for fly ash-mediated formation of PCBs in the secondary copper industry, and the mechanisms involved, were studied in laboratory thermochemical experiments. The total PCB concentrations were 37–70 times higher than the initial concentrations. Thermochemical reactions on the fly ash amplified the potential toxic equivalents of PCBs. The formation of PCBs over time and the effect of temperature were investigated. Based on analyses of PCB homologue profiles with different reaction conditions, a chlorination mechanism was proposed for forming PCBs in addition to a de novo synthesis mechanism. The chlorination pathway was supported by close correlations between each pair of adjacent homologue groups. Formation of PCBs and multiple persistent organic pollutants, including polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated naphthalenes, occurred during the tests, indicating that these compounds may share similar formation mechanisms.

Bacterial degradation of a mixture obtained through the chemical modification of polychlorinated biphenyls by polyethylene glycols

Polychlorinated biphenyls (PCBs), also known by the trade name Sovol, are toxic industrial wastes. They have been subjected to chemical treatment by polyethylene glycols (PEGs) and potassium hydroxide. As a result of the interaction of the Sovol with various molecular mass PEGs (MMPEG-4 ∼ 200, MMPEG-22 ∼ 1000), water-soluble mixtures M1 and M2 containing mono(polyethylene glycol)oxy-derivatives (PCB-PEG-4 and PCB-PEG-22), polychlorobiphenylols, and unreacted PCB congeners (PCB 44, PCB 47, PCB 49, PCB 52, and PCB 66) were obtained. It was shown for the first time that mixtures M1 and M2 are susceptible to bacterial degradation without their fractionation. According to the gas-liquid chromatography with flame-ionization and mass-spectrometric detection, the Rhodococcus wratislaviensis KT112-7 strain degraded all of the chemical compounds occurring in the mixtures. In a 5-day experiment, it was found that the KT112-7 strain decomposes mono(polyethylene glycol)oxy-derivatives completely (by 100%) and polychlorobiphenylols and PCB congeners by 90–95% in the M1 and M2 mixtures. The culture medium did not contain transformation products, whereas free chlorine ions were accumulated (72–94% of the maximum possible amount). Thus, the use of the chemical modification and consecutive bacterial degradation provided an effective destruction of technical PCB mixtures with a high content of highly chlorinated congeners.

Source apportionment of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in ambient air of an industrial region in Turkey

Source apportionment is generally applied to a time series of data collected at a single site. However, in a complex airshed containing several different sources, it may be helpful to collect samples from multiple sites to ensure that some of them have low contributions from specific sources, thus the boundaries can be properly defined. Ambient air polycyclic aromatic hydrocarbon (PAH) and polychlorinated biphenyls (PCB) samples (n = 160) were collected at 40 sites during four seasons (summer, fall, winter, and spring) between July 2009 and April 2010 in the heavily industrialized Aliaga region in Turkey to investigate their spatial, seasonal variations and to identify possible PAH and PCB sources. The newest version of EPA PMF (V5.0) having the capability of handling multiple site data was used for source apportionment. Five PAH sources were identified as biomass and coal combustion, iron–steel production, unburned crude oil and petroleum products, and diesel and gasoline exhaust emissions with contributions of 40, 27, 27, 3, and 3%, respectively. The sources of PCBs were identified as iron–steel production (consisting of steel-making and ship breaking activities), coal and wood combustion, and evaporative emissions from technical PCB mixtures with contributions of 57, 31, and 12%, respectively.

Contamination and source assessment of metals, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons in urban soils from Addis Ababa, Ethiopia

Urban areas in developing countries are facing vast environmental problems as a result of rapid urbanization and industrialization. Of major concern is the contamination of soils which are increasingly becoming sinks for environmental pollutants. However, to date only little is known about the pollution in the megalopolises of developing countries. The aim of this study was to assess the contamination and potential sources of metals, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in the urban environment of Addis Ababa, the capital of Ethiopia. The investigation revealed the presence of most of the analyzed pollutants in soil and sediment samples with total concentrations (dry wt) of PAHs ranging from 186 to 3150 µg kg−1, PCBs from 0.4 to 19 µg kg−1, Cu from 14 to 173 mg kg−1, Zn from 36 to 440 mg kg−1, Pb from 9 to 700 mg kg−1, and Ni from 16 to 72 mg kg−1. In addition, polyaromatic sulfur heterocycles, typical for oil and petrol residues, were detected in several soil samples. Source identification approaches revealed that Pb, Zn, and Cu are most likely derived from pyrolytic sources, with elevated values in samples related to waste combustion and traffic emissions. Ni is most probably of geogenic origin. For PCBs it is indicated that they are derived from a single source. However, correlations with technical PCB mixtures were inconsistent. PAHs originate from the combustion of biomass, vehicular exhausts, and petrogenic sources.

Distribution of PCBs in sediments of the Červený potok, stream contaminated by technical PCB mixtures Delor, Czech Republic

Distribution of PCBs in sediments of the Červený potok, stream contaminated by technical PCB mixtures Delor, Czech RepublicThe results of measurement of polychlorinated biphenyls (PCBs) in surface bottom sediments contaminated by technical PCB mixtures Delor collected from the Červený potok (stream in the Litavka River catchment), Czech Republic in 2008 are presented. The sediment samples of two different grain size fractions (&lt; 2 mm and &lt; 200 μm) were analyzed for 8 congeners of PCBs using Soxhlet extraction and gas chromatography (GC-ECD). Total concentrations of PCBs ranged from 15.3 to 997 ng g-1 (dry weight) in &lt; 2 mm fraction and from 29.9 to 952 ng g-1 in &lt; 200 μm fraction, where PCBs 28, 52, 101, 138, 153, 180 and 194 were found in all the samples. The highest levels of PCBs were found in sediment collected from the area below the discharge of municipal wastewater treatment plant and local engineering industry in the Komárov village. High percentage of PCBs 28, 153 and 138 (22-74%, 5-22% and 5-20% respectively) indicates the contamination by PCBs commercial mixtures Delor 103 and Delor 105 (an equivalent of AROCLOR 1242 and 1254). The result of PCA analysis indicates that the more highly chlorinated

Prenatal Aroclor 1254 exposure and brain sexual differentiation: Effect on the expression of testosterone metabolizing enzymes and androgen receptors in the hypothalamus of male and female rats

Polychlorinated biphenyls (PCBs) are industrial pollutants detected in human milk, serum and tissues. They readily cross the placenta to accumulate in fetal tissues, particularly the brain. These compounds affect normal brain sexual differentiation by mechanisms that are incompletely understood. The aim of this study was to verify whether a technical mixture of PCBs (Aroclor 1254) would interfere with the normal pattern of expression of hypothalamic aromatase and 5-alpha reductase(s), the two main enzymatic pathways involved in testosterone activation and of androgen receptor (AR). Aroclor 1254 was administered to pregnant rats at a daily dose of 25 mg/kg by gavage from days 15 to 19 of gestation (GD15–19). At GD20 the expression of aromatase, 5-alpha reductase types 1 and 2 and androgen receptor (AR) and aromatase activity were evaluated in the hypothalamus of male and female embryos. The direct effect of Aroclor was also evaluated on aromatase activity adding the PCB mixture to hypothalamic homogenates or to primary hypothalamic neuronal cultures. The data indicate that aromatase expression and activity is not altered by prenatal PCB treatment; 5-alpha reductase type 1 is similarly unaffected while 5-alpha reductase type 2 is markedly stimulated by the PCB exposure in females. Aroclor also decreases the expression of the AR in females. The observed in vivo effects are indicative of a possible adverse effect of PCBs on the important metabolic pathways by which testosterone produces its brain effects. In particular the changes of 5-alpha reductase type 2 and AR in females might be one of the mechanisms by which Aroclor exposure during fetal development affects adult sexual behavior in female rats.

Carcinogenicity of “Non-Dioxinlike” Polychlorinated Biphenyls

Complex technical mixtures of polychlorinated biphenyls (PCBs) cause liver and thyroid neoplasms in rodents, whereas very few data are available on the carcinogenic potency of single non-dioxinlike (NDL) PCB congeners. In most genotoxicity assays technical PCB mixtures and individual congeners were inactive, suggesting that PCBs act as indirect, nongenotoxic carcinogens. Various mechanisms, including suppression of apoptosis in preneoplastic cells or inhibition of intercellular communication, have been suggested to be active in liver tumor promotion by PCBs. A decrease in thyroid hormone levels after PCB treatment has been suggested to play a role in the development of thyroid neoplasms in rats; however, other mechanisms may also be involved. Results from a chronic carcinogenicity study in rats indicate that not the dose of total PCBs but the total TCDD or toxic equivalents (TEQs) associated with “dioxinlike” (DL) constituents within a technical mixture are mainly if not exclusively responsible for the development of liver neoplasms in female rats. Quantitative comparison reveals almost identical dose-response curves for the total TEQs in various technical PCB mixtures and for TCDD as inducers of hepatic neoplasms in female rats. Tumor promotion experiments have shown, however, that, after initiation with a genotoxic carcinogen, technical PCB mixtures and individual DL-and NDL-PCBs act as liver tumor promoters in rodents. Based on these data, a weak carcinogenic potency of individual NDL-PCB congeners cannot be excluded. In epidemiological studies, increased mortality from cancers of the liver, gallbladder, biliary tract, gastrointestinal tract, and from brain cancer and malignant melanoma were observed in workers exposed to a series of technical PCB mixtures. A significant association between PCB concentrations in adipose tissue and non-Hodgkins lymphoma was found in another study. While in all human studies mixed exposure to DL-and NDL-PCBs occurred, no comprehensive data are available on the relative contribution of NDL-PCBs to the overall external and/or internal PCB exposure in those cohorts.

Effects of Developmental Exposure to 2,2′,4,4′,5-Pentabromodiphenyl Ether (PBDE-99) on Sex Steroids, Sexual Development, and Sexually Dimorphic Behavior in Rats

Increasing concentrations of polybrominated flame retardants, including polybrominated diphenyl ethers (PBDEs), in breast milk cause concern about possible developmental effects in nursed babies. Because previous studies in rats have indicated effects on sex steroids and sexually dimorphic behavior after maternal exposure to polychlorinated biphenyls (PCBs), our goal in the present study was to determine if developmental exposure to 2,2′,4,4′,5-pentabromodiphenyl ether (PBDE-99) induces similar endocrine-mediated effects. Pregnant rats were exposed to vehicle or PBDE-99 (1 or 10 mg/kg body weight, daily during gestational days 10–18). For comparison, we also included a group exposed to the technical PCB mixture Aroclor 1254 (30 mg/kg body weight, daily). PBDE exposure resulted in pronounced decreases in circulating sex steroids in male offspring at weaning and in adulthood. Female offspring were less affected. Anogenital distance was reduced in male offspring. Puberty onset was delayed in female offspring at the higher dose level, whereas a slight acceleration was detected in low-dose males. The number of primordial/primary ovarian follicles was reduced in females at the lower dose, whereas decline of secondary follicles was more pronounced at the higher dose. Sweet preference was dose-dependently increased in PBDE-exposed adult males, indicating a feminization of this sexually dimorphic behavior. Aroclor 1254 did not alter sweet preference and numbers of primordial/primary and secondary follicles but it did affect steroid concentrations in males and sexual development in both sexes. PBDE concentrations in tissues of dams and offspring were highest on gestational day 19. These results support the hypothesis that PBDEs are endocrine-active compounds and interfere with sexual development and sexually dimorphic behavior.

Polychlorinated Biphenyl Concentrations in Adult Chinook Salmon (Oncorhynchus tshawytscha) Returning to Coastal and Puget Sound Hatcheries of Washington State

Identifying the source of polychlorinated biphenyls (PCBs) is the first step to eliminating contamination within anadromous salmonids and other aquatic species. We evaluated PCB concentrations in the muscle tissue of 4-year old Puget Sound and coastal hatchery Chinook salmon in an effortto identify potential locations where contamination occurs. Ten muscle samples were taken from each of two Puget Sound hatcheries and two coastal hatcheries in Washington State to determine PCB concentrations. Two technical mixtures of PCBs, Aroclor 1254 and Aroclor 1260, were measured in the tissue samples collected. Aroclor 1254 was detected in all samples, while Aroclor 1260 was detected in 16 of 40 samples. Generalized linear modeling (GLM) was used to evaluate the influence of region (Puget Sound and coast), hatchery, sex, fish length, and percent lipids on PCB concentrations. Twenty different GLMs representing multiple null hypotheses were ranked using Akaike Information Criterion (AIC). Six of the 20 models evaluated had substantial support for being the best model to describe PCB concentrations in Chinook salmon. The six models with substantial support were region and lipids; region; hatchery and lipid; region and sex; region, sex, and lipids; and region and length. Region appears to be the most influential variable explaining the variation in PCB concentrations in Chinook salmon in the Pacific Northwest. PCB concentrations in Chinook salmon muscle tissue from Puget Sound hatcheries were significantly greater (mean 49.26 microg/kg wet weight and standard deviation 40.55 microg/kg) than those from coastal hatcheries (mean 17.41 microg/kg wet weight and standard deviation 6.8 microg/kg). Our results suggest that some contamination likely occurs in the Pacific Ocean. However, a larger source likely exists within Puget Sound or along the migratory route of Puget Sound Chinook salmon. The observation of PCBs in Chinook salmon also has important implications for human health and salmon carcass supplementation.

Study on hydrodechlorination of polychlorinated biphenyls during reductive pyrolysis in the presence of a catalyst

For the first time an experimental set-up, called atmospheric pressure temperature programmed reduction (AP-TPR) applied in the speciation study of sulphur compounds in coal, has been used in the hydrodechlorination study of polychlorinated biphenyls (PCBs) with several specifically designed catalysts. Quantitative results concerning the degree of dechlorination were obtained using a potentiometric detection system equipped with a Cl − selective electrode. Using a MS detection system, qualitative interpretation of the hydrodechlorination process (HDCl) of PCB as a function of the systematical increasing temperature could be formulated. Highly chlorinated organic compounds, i.e. decachlorobiphenyl (CB 209) and a technical mixture of PCBs (Aroclor 1254), were subjected to reductive pyrolysis in a flow of hydrogen in the presence of a catalyst. A number of nickel catalysts on carbon and silica were prepared using an optimized spray drying technique. A commercial carbon supported palladium catalyst was also tested. Pd/C leads to a complete removal of chlorine from CB 209 and to a smaller extent from Aroclor 1254 and at a much lower temperature than for the NiC catalysts. The HDCl of Aroclor 1254 and CB 209 catalysed by Ni/C starts at 300 and 350 °C, respectively. The highest removal of chlorine is achieved using Ni/C catalyst with the lowest amount of NiO being 3 wt%. While nickel on silica support is found to be inactive for the HDCl reaction under the conditions of AP-TPR analysis. AP-TPR-MS study shows that biphenyl structure is decomposed to benzene, toluene, styrene and propenyl benzene with a maximum evolution temperature higher than the HDCl process but depending on the catalyst and PCBs. It can be concluded that AP-TPR method can be considered as a simple method for preliminary testing the activity of catalysts for HDCl process.

Simple Immunoassay for Detection of PCBs in Transformer Oil

A rapid and inexpensive procedure to detect polychlorinated biphenyls (PCBs) in transformer oil is needed to facilitate identification and removal of PCB contaminated transformers. Here we describe a simple two-step liquid-liquid extraction using acidic dimethyl sulfoxide in conjunction with an immunoassay for detecting PCBs in transformer oil. The process described is faster and simpler than any previous immunoassay while maintaining comparable detection limit and false negative rate. Cross reactivity data, characterizing the immunoassay response to the four Kanechlor technical mixtures of PCBs in oil, are presented. Forty-five used transformer oil samples were analyzed by gas chromatography-high-resolution mass spectrometry and were also evaluated using the immunoassay protocol developed. Results presented show zero false negatives at a 1.4 ppm nominal cutoff for the transformer oils analyzed.