Coplanar polychlorinated biphenyls (PCB) in indoor air

Indoor air levels of coplanar polychlorinated biphenyls (mono- and non-ortho substituted PCB) of various buildings were determined. As a consequence of the presence of joint sealings containing PCB, total PCB concentrations in indoor air up to 4,200 ng/m3 were detected (data based on a survey including 29 sampling sites). In a PCB contaminated industrial building, total indoor air PCB levels up to 13,000 ng/m3 were measured. Typical PCB congeners in indoor air include PCB 28, PCB 52, and PCB 101. Concentrations of coplanar (dioxin-like) PCB have been determined for six different sites. The most abundant coplanar PCB congener in indoor air is PCB 118, followed by PCB 105, PCB 123, and PCB 77 in various order. Levels of coplanar PCB, expressed as toxicity equivalents (TEG), do correlate well with the total indoor air PCB concentration: a total PCB level of 1,000 ng/m3 corresponds to a concentration of coplanar PCB of 1.2 pg TEQ/m3. Based on this correlation and on an indoor air PCB level of 6,000 ng/m3 (tentative guideline value for PCB in indoor air in Switzerland based on a daily exposure of 8 h), the maximum daily intake of coplanar PCB via indoor air was estimated to be 0.6 pg TEQ/kg body weight.     

Temporal trends of polychlorinated biphenyls in precipitation and air at chicago

Polychlorinated biphenyl (PCB) concentrations in precipitation (1997-2003) and in the atmospheric gas phase (1996-2003) collected in Chicago, IL, are reported. These data were obtained as part of the Integrated Atmospheric Deposition Network. For comparison, PCB concentrations at a remote site, Sleeping Bear Dunes on the northeastern shore of Lake Michigan, are also reported. Much higher PCB concentrations in both precipitation (7.1 +/- 0.9 ng/L) and the gas phase (1.4 +/- 0.1 ng/m3) at Chicago compared to Sleeping Bear Dunes (1.1 +/- 0.1 ng/L and 0.1 +/- 0.08 ng/m3, respectively) indicate that Chicago is a source of PCBs to the Great Lakes. A long-term decreasing trend of PCB concentrations in precipitation was observed at Chicago with a half-life of 6.8 +/- 3.1 years. The corresponding half-life for PCB concentrations in the gas phase was 7.7 +/- 1.1 years. The significant long-term decrease of PCB concentrations in precipitation and the gas phase in Chicago suggests that regulatory efforts are working, at least in this city.     

Seasonal and spatial variation of polychlorinated naphthalenes and non-/mono-ortho-substituted polychlorinated biphenyls in arctic air

Archived extracts of weekly air samples collected at remote arctic monitoring stations at Alert and Tagish, Canada, and Dunai Island, Russia, in 1994-1995 were combined into 4-week composites and analyzed for levels and seasonal trends of polychlorinated naphthalenes (PCNs) and non- and mono-ortho-substituted polychlorinated biphenyls (PCBs). Mean annual sigmaPCN concentrations were 0.69, 0.82, and 0.38 pg/m3 at Alert, Dunai, and Tagish, respectively. PCNs exhibited a seasonal trend at Alert and Dunai, with higher levels occurring during winter when air masses originating over Eurasia influence the high arctic and coincide with the haze period. Episodic, trans-Pacific transport impacted PCN concentrations at Tagish. A seasonal trend was not evident for the non-/mono-o-PCBs. The contrary PCN and non-/mono-o-PCB trends indicate that the sources of these two compound classes to arctic air differ, and that atmospheric transport from source regions has a greater influence on PCN levels than for non-/ mono-o-PCBs. PCNs apparently originating from combustion sources contribute to levels in winter, as indicated by the presence of combustion marker congeners, but evaporative emissions from source regions are likely the dominant source. PCNs contributed 71 and 75% of dioxin toxic equivalents (TEQ) relative to the non-/mono-o-PCBs at Alert and Dunai and 30% at Tagish during the winter months, demonstrating the toxicological importance of PCNs as a compound class relative to PCBs.     

Enhanced anaerobic biodegradation of polychlorinated biphenyls in burnt soil culture

Anaerobic microbial degradation of polychlorinated biphenyls (PCBs) in Kanechlors-300 and -400 was enhanced significantly by adding burnt soil originally obtained from an uncontaminated paddy soil to the microbial culture. The maximum PCB-degrading activity was 0.49 nmol-Cl/ml-culture/day (238 ng-total-PCBs/ml-culture/day), where the degradation was observed in most of the congeners in Kanechlors-300 and -400: not only in meta- and para-substituted congeners but also ortho-substituted congeners. The degradation of PCBs occurred during the increase in the microbial population with acetate as the main electron donor. The ratio between the consumption of electron donors and the dechlorination of PCBs was revealed to be 93.9 nmol-Cl/mmol-e-donor, which is also the dechlorination efficiency over 56 d of incubation. The addition of acetate and lactate several times into the culture rejuvenated the activity.     

Concentrations and chiral signatures of polychlorinated biphenyls in outdoor and indoor air and soil in a major U.K. conurbation

Concentrations and chiral signatures of polychlorinated biphenyls (PCBs) were measured in outdoor air (using polyurethane foam (PUF)--disk passive samplers) and surface soil samples taken at approximately monthly intervals over 1 year at 10 locations on a rural-urban transect across the West Midlands of the U.K. In both air and soil, concentrations clearly decrease with increasing distance from the city center, supporting the existence of an urban "pulse", that indicate the West Midlands conurbation to be a source of PCBs to the wider environment. Concentrations of PCBs in outdoor air samples in this study are well below those reported previously for indoor air in the West Midlands. This, combined with comparison of chiral signatures in outdoor air and soil with those in samples of indoor air taken in the West Midlands, suggest strongly that the principal contemporary source of PCBs in this conurbation is ventilation of indoor air and not volatilization from soil. Future reductions in PCB concentrations in outdoor air and ultimately human exposure appear best achieved by action to remove remaining sources of PCBs from existing structures.     

Long-term fate of polychlorinated biphenyls and polycyclic aromatic hydrocarbons in an agricultural soil

Laboratory studies are useful for understanding the behavior of persistent organic pollutants (POPs) in soil, although such investigations do not always relate directly to field conditions. Outdoor lysimeter studies may be used to overcome this problem. This work aimed to investigate the behavior of two polycyclic aromatic hydrocarbons (PAHs) (fluoranthene and benzo[a]pyrene) and two polychlorinated biphenyls (PCBs; congeners 28 and 52) in soil, using lysimeters established in 1990 atthe Agrosphere Institute (Forschungszentrum Julich GmbH, Germany). The two PAHs were in one lysimeter, and the PCBs were in a second lysimeter. Afurther aim of the study was to determine soil half-lives for each of the contaminants. The overall decline in PAH concentrations was considerably greater than forthe PCBs over the 152 month study. The PCBs exhibited greater chemical extractability than the PAHs and were demonstrated to have migrated through the soil column to a greater extent than the PAHs. Loss of PCBs from surface soil was not considered to have been congener specific for the two PCB congeners in this study. The two PAHs varied in their extents of total loss and movement through the soil column. Soil half-lives were determined as 10.9 y for [12C]PCB 28, 11.2 yr for [12C]PCB 52, 2.7 yr for benzoqpyrene, and 32 d (phase 1) to 38 yr (phase 2) for fluoranthene. These are shown to disagree with some previous estimates of POP half-lives in soil, suggesting that previous studies underestimated persistence by 10-fold or more.     

Polychlorinated biphenyls in Chinese surface soils

Polychlorinated biphenyl (PCB) concentrations in surface soil samples (0-20 cm) from 52 sites (4 background, 39 rural, and 9 urban) across China in 2005 are presented. The average concentration of total PCBs among all the sites was 515 pg/g dry weight (dw), approximately one-tenth of that in global background soil in 1998. Differences of less than 1 order of magnitude were found between all background and rural sites, indicating a generally uniform distribution of PCBs in Chinese background/rural surface soil. While the major PCB homologue group in global background soil is hexa-PCB followed by penta-PCB, the major PCB homologue group in Chinese background/rural soil is tri-PCB followed by di-PCB, indicating a rather fresh signature in comparison to the much weathered PCBs in global surface soil. The correlation between sigmaPCBs and also each PCB homologue group per soil organic carbon (SOC) content in background/rural soil with longitude from 80 degrees to 122 degrees East was studied. The results indicated the strong influence of PCBs concentrations in Chinese background/rural soil by proximity to source region and SOC content, and also provided evidence for urban fractionation effect of PCBs in soil in the city of Shanghai and the longitudinal fractionation of PCBs in Chinese background/ rural soil from east to west. This work is the first comprehensive and spatial study of its kind for PCBs in Chinese surface soil on a national scale, and the data presented in this study can provide baseline information for establishing a long-term PCBs monitoring program in China.     

Causes of variability in concentrations of polychlorinated biphenyls and polybrominated diphenyl ethers in indoor air

Airborne concentrations of PCBs and PBDEs were measured in offices, homes, public environments, and cars. Variations in concentrations between different rooms in the same domestic and office buildings, showed some intra-building variability for both compound groups. Stepwise multiple linear regression analysis revealed no clear and consistent relationships between log-normalized concentrations of PCBs and PBDEs in homes and offices and factors such as the number of personal computers. This is considered to reflect the complexity of relationships between indoor air contamination and microenvironment characteristics. The influence of personal computers was demonstrated when PBDE concentrations in one office fell appreciably following the exchange of a computer constructed in 1998 for one dating from 2003. Concentrations of PCBs in buildings constructed between 1950 and 1979 were significantly higher (p < 0.001) than in those constructed since. When two of the most contaminated cars were omitted as outliers, a significant (p < 0.01) positive linear relationship was detected between PBDE concentrations and vehicle age. Concentrations of PCBs and PBDEs were monitored throughout a calendar year in four homes and four offices. Although concentrations in warmer months usually exceeded those in colder months, seasonal variability in indoor contamination appears less significant than observed previously for outdoor air.     

Chiral signatures show volatilization from soil contributes to polychlorinated biphenyls in grass

Enantiomer fractions (EFs) of PCB 95 and concentrations of PCBs 28/31, 52, 101, 118, 138, 153, and 180 were determined in air. Samples were taken at ~14 day intervals on a vertical gradient at an urban background site in Birmingham U.K. in summer 2009 (114 days) and spring 2010 (84 days). EFs in air at 3 cm height were nonracemic (average 0.453 (2009) and 0.468 (2010)) and differed significantly (p < 0.05) from the racemic EFs in air at 10, 40, 90, and 130 cm. EFs in soil (average 0.452 (2009) and 0.447 (2010)) closely matched those in air at 3 cm, while those in grass (average 0.468 (2009) and 0.484 (2010)) were intermediate between those in soil and the racemic EFs in air at ≥ 10 cm. This implies that at the study site, PCBs volatilize from soil to an extent discernible only at the soil:air interface, and that PCBs in grass arise due to foliar uptake of volatile emissions from soil. Atmospheric concentrations of ΣPCBs increased significantly (p < 0.05) with increasing height. Combined with the chiral signature data, this suggests the influence of PCB emissions from soil on airborne concentrations decreases with altitude, while that of emissions from the built environment increases.     

Exchange of polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) between air and a mixed pasture sward

To improve understanding of air-to-vegetation transfer of persistent organic pollutants (POPs), uptake and depuration of polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) between grass sward and air was investigated. Pasture swards were placed in fanned (2 m s(-1) wind speed) and unfanned conditions for a period of 20 days and sampled at intervals. Depuration was carried out after a short (4 days) and a long (14 days) exposure period. Prior to contamination, a mixed pasture sward at a semi-rural location contained sigmaPCN concentrations 15-20% of the sigmaPCB concentration. Uptake of both PCBs and PCNs was broadly linear in fanned and unfanned conditions over the 20-day period, i.e., the pasture did not reach equilibrium with the air. Uptake rates (fluxes) were greater under the fanned conditions. The difference in uptake rates between fanned and unfanned conditions increased with degree of chlorination for both PCBs and PCNs, ranging between a factor of 2 for tri-chlorinated PCBs and PCNs and a factor 5 for octa-chlorinated PCBs. Depuration results over the first hours were very scattered, showing an initial period of loss, followed by an increase in concentrations, possibly as a result of re-volatilization of PCBs from the soil in the trays, with consequent recapture by the overlying sward. Rapid clearance was observed over the following days, but depuration of PCBs and PCNs was still incomplete after 14 days, with 20% of the initial concentration of the sigmaPCBs and 10% of the sigmaPCNs retained by the sward. There was no difference in the proportion of POPs retained in the sward between the 4- and 14-day contamination treatments. POP-specific differences in the amount of compound "trapped" in leaves after contamination were observed. The results show that, although changes in the rate of air movement around a pasture have an effect on the uptake rate of POPs into the vegetation, plant-side resistance controls both the air-to-pasture and pasture-to-air exchange of gas-phase PCBs and PCNs; i.e., differences between plant species in cuticle composition and/or structure affecting the permeability of the cuticle are of greater importance than differences in leaf morphology affecting aerodynamic roughness.     

鱼油中多氯联苯检测方法的研究

目的建立毛细管气相色谱法测定鱼油中多氯联苯的方法。方法用氢氟酸和浓硫酸的混合溶液消解样品,以正己烷提取、浓硫酸净化后,用毛细管气相色谱法测定。结果方法的回收率为92.6%~105.2%,相对标准偏差(RSD)为2.98%~4.71%,最低检出限为0.25~0.48μg/kg。结论该方法简便、快捷,其灵敏度、准确度和精密度均能满足鱼油中多氯联苯分析的要求。     

Variable air temperature response of gas-phase atmospheric polychlorinated biphenyls near a former manufacturing facility

Many investigations of gas-phase atmospheric PCB show a strong relationship between concentration and air temperature, especially near PCB sources. Comparative gas-phase atmospheric PCB trends during an annual temperature regime at two sites near a former PCB manufacturing plant and nearby PCB landfills in Anniston, AL, indicate a departure from this trend. The Mars Hill sampling site, located closest to the plant and landfills, shows an annual average sigmaPCB concentration of 27 ng m(-3) (ranging from 8.7 to 82 ng m(-3)) three times the average at Carter, 1.5 km away (9 ng m(-3), ranging from 1.1 to 39). However, total PCB and congener concentrations vary more with air temperature at Carter where PCB are evaporating from surfaces during warmer weather. The slopes of the Clausius-Clapeyron plots of 18 of the most concentrated congeners representing dichloro- through heptachlorobiphenyl homologues are significantly higher at the Carter site. While some of the atmospheric PCB at Mars Hill is derived from ground surface evaporation, the source of much of it apparently is the material buried in the landfills, which has different thermal properties than surface materials and is not in equilibrium with air temperature.     

婴儿配方乳粉中二噁英及其类似物污染分析

目的 了解婴儿配方乳粉中二噁英及其类似物污染水平,为相关研究提供基础数据.方法 采集601份市售婴儿配方乳粉,按照GB 5009.205-2013《食品安全国家标准食品中二噁英及其类似物毒性当量的测定》对17种多氯代苯并二噁英和多氯代苯并呋喃(PCDD/Fs)和12种二噁英样多氯联苯(dl-PCBs)进行测定.结果 P...     

Risk assessments of polychlorinated dibenzo- p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls in food

The polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), and dioxin-like polychlorinated biphenyls (dioxin-like PCB) are ubiquitous in food of animal origin and accumulate in fatty tissues of animals and humans. The most toxic congener is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The toxic responses include dermal toxicity, immunotoxicity, carcinogenicity, and reproductive and developmental toxicity. Toxic equivalency factors have been established for the other PCDD, PCDF and dioxin-like PCB relative to TCDD, and the combined toxicity of a sample can be expressed as toxic equivalent (WHO-TEQ). The EC Scientific Committee for Food evaluated these compounds in 2001. The assessment used the most sensitive adverse toxicological end-points of TCDD in experimental animals. These were developmental and reproductive effects in the male offspring of rats administered TCDD during pregnancy. Because of the large difference between rats and humans in the biological half-life of TCDD, the assessment used a body burden approach to compare across species and derived a tolerable weekly intake of 14 pg TCDD/kg of body weight (bw), which was extended to include all the 2,3,7,8-substituted PCDD and PCDF, and the dioxin-like PCB, and expressed as a group tolerable weekly intake of 14 pg WHO-TEQ/kg bw. The FAO/WHO Joint Expert Committee on Food Additives (JECFA) performed a similar assessment whereas the US Environmental Protection Agency (US EPA) has paid more attention to human data on carcinogenicity.     

Pan-arctic river fluxes of polychlorinated biphenyls

Observations of polychlorinated biphenyls (PCB) concentrations in fluvial surface sediments near the mouths of the six Great Arctic Rivers (GARs; Ob, Yenisey, Lena, Indigirka, Kolyma, and Mackenzie) were combined with annual dissolved organic carbon (DOC) and particulate organic carbon (POC) loadings and hydraulic discharge to estimate the pan-Arctic river flux of PCBs. The highest total-phase fluxes of ∑(13)PCB were found for the Ob River, with 184 kg/yr and the smallest for the Indigirka River with 3.9 kg/yr. Consistent with a continent-scale trend among the Eurasian GARs of increasing POC concentrations eastward, which is extending to the North American Mackenzie River, a general shift in the estimated PCB partitioning from dissolved to particle-associated flux was found toward the east. Pentachlorinated and hexachlorinated PCBs constituted the majority (>70%) of the total PCB fluxes in the Eurasian Rivers. In contrast, trichlorinated and tetrachlorinated congeners were the most abundant in the Mackenzie (≈ 75%). The total ∑(13)PCB fluxes from the pan-Arctic rivers are here estimated to be ～0.4 tonne/yr. This is geochemically consistent with the inventory of total PCBs in the Polar Mixed Layer of the entire Arctic Ocean (0.39 tonne) and about a factor 2 less than two new estimates of the PCB settling export to Arctic subsurface waters. Hence, the yearly Great Arctic River PCB fluxes only represent 0.001% of the historical PCB emission into the global environment. To our knowledge, this is the first estimate of circum-Arctic river flux of any organic pollutant based on a comprehensive investigation of the pollutants in several rivers and it contributes toward a more complete understanding of large-scale contaminant cycling in the Arctic.