Background air levels of polychlorinated biphenyls in China

Measurements of the atmospheric concentrations of polychlorinated biphenyls (PCBs) were taken in 11 background sites geographically distributed throughout China. Active high-volume samplers were employed during two deployment periods between November 2007 and November 2008. 12 dioxin-like and 7 indicator PCBs were identified and measured. To keep the consistency, the two sampling periods were set in the same seasons (autumn and winter) and there were few variations between the results at all sites. The congener profile of indicator PCBs was dominated by CB28 and CB52. The most abundant mono-ortho congener was CB118, and the most abundant non-ortho congener was CB77. This study is the first systematic investigation into background atmospheric PCB levels in China. The background indicator ∑₇PCB levels in China are similar to those obtained at other background areas around the world.     

The degradation of polychlorinated biphenyls by micro-organisms

An investigation is described concerning the effects of two micro-organisms cultures on single compounds and multi-component mixtures of polychlorinated biphenyls (PCBs).Several low chlorine PCB compounds can be degraded easily with these cultures and, in favourable circumstances, some compounds containing up to six chlorine atoms per molecule can be degraded.In certain multi-component commercial mixtures some PCB compounds are degraded more readily than if present singly. The significance of this is discussed, particularly the fact that work on single compounds does not enable predictions to be made about the behaviour of commercial mixtures in the environment. Some tentative explanations are suggested for the behaviour of the mixtures exposed to these cultures.     

Solubility of polychlorinated biphenyls and capacitor fluid in water

A quantitative method to determine the solubility of polychlorinated biphenyls (PCBs) and used capacitor fluid in water was developed employing high-resolution glass capillary-column gas chromatography. The responses of the electron capture detector to mono-, di-, tri- and tetra-chlorobiphenyls and an internal standard were used to estimate the solubility of the PCBs. Results of the rate of dissolution of Aroclor 1242 and used capacitor fluid in water indicated that a period of five months was required to reach equilibrium. The water-solubile fractions of Aroclor 1242 and used capacitor fluid (Aroclor 1242-impregnated) were found to be identical. Certain isomers of the mono-, di- and poly-biphenyls in Aroclor 1242 were relatively soluble and were identified as 2-mono-, 2,4′-di-, 2,5.2′-tri-, 2.3,2′-tri-, 2,5.4′-tri-, 2,5.2′,5′-tetra-, 2,4.2′,5′-tetra-, 2,4.2′,4′-tetra-, 2,3.2′,5′-tetra- and 2,4.3′,4′-tetra-chlorobiphenyl. In general, the water-soluble fractions of the PCB mixtures were richer in the lower chlorinated isomers than the original PCB mixtures. The solubilities of Aroclor 1016, 1221, 1242, and 1254 were 906. 3516, 703 and 70μg1⁻¹, respectively, whereas the solubility of the used capacitor fluid was the same as that of Aroclor 1242.     

Gas-particle partitioning of polychlorinated naphthalenes and non- and mono-ortho-substituted polychlorinated biphenyls in arctic air

Gas-particle partitioning relationships were developed for partitioning of polychlorinated naphthalenes (PCNs) and non- and mono-ortho PCBs in arctic air by regressing observed gas-particle partition coefficients, K(P), at Alert and Dunai in the high Arctic with temperature-adjusted experimental vapor pressures (p(L) degrees ) and octanol-air partition coefficients (K(OA)). Slopes were near -0.5 and 0.5 for log p(L) degrees and log K(OA), respectively, at both sites, indicating that aerosol characteristics and partitioning processes were similar at the two sites. The K(OA) absorption model provided an adequate estimate of the percentage of PCNs and non-/mono-ortho PCBs associated with particulate matter, based on fraction of organic matter (f(OM)) ranging from 0.074 to 0.12, compared to the Junge-Pankow adsorption model, which slightly over-estimated the distribution on particles. There were no indications that partitioning to soot carbon influences the observed gas-particle distribution for PCNs and non-/mono-ortho PCBs in arctic air as has been observed for PAHs in recent studies at temperate locations.     

Partitioning of selected polychlorinated biphenyls to natural sediments

The partitioning of two polychlorinated biphenyl mixtures (Aroclor 1016 and 1242) and two tetrachlorobiphenyl isomers (2,5,3′,4′ and 2,6,2′,6′ tetrachlorobiphenyl) between water and four natural sediments was evaluated in laboratory investigations. For both Aroclor mixtures, the extent of adsorption was comparable on all four natural sediments studied. For individual isomers, partitioning was comparable with that observed for the mixtures. Both particle size distribution and total organic carbon were important factors in determining the extent of partitioning for the two isomers; but in the case of the mixtures, there was no correlation with organic content.     

Evidence for the transfer of polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans from soil into biota

The concentrations of six indicator and co-planar polychlorinated biphenyls (PCBs), 17 polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans (PCDD/Fs) were determined in soil and associated biota samples collected from a polluted and wasted farmland in southern China. The sum of six indicator PCBs (Nos 28, 52, 101, 138, 153 and 180) concentrations in biota samples were proportional to the total amount of PCBs that transferred from soil to the corresponding biota samples, and the sum six indicator PCB congeners in samples were about 20% of the total PCBs, respectively. The ratios of the sum six indicator PCBs and the total PCBs in samples collected in the same area were approximately equal. The sums of six indicator PCBs were proportional to the total PCBs that transferred from soil to plant, while the co-planar PCBs were not. Analysis of individual PCB and PCDD/F congener signatures in soil revealed the original pollutant source after transportation and biodegradation for 14 years using principal component analysis (PCA). The pattern of PCBs in soils and plants could reflect the original pollution source after transportation and biodegradation for 14 years, while the pattern of PCBs in the terrestrial animals could not reflect the primary source. The consumption foods in this region such as foraging chicken eggs, foraging duck eggs, and loach (Misgurnus anguillicaudatus) were highly contaminated, the total toxicity equivalent (TEQ) was up to 784 pg WHO-TEQ/g on basis lipid in foraging chicken eggs.     

A material balance study of polychlorinated biphenyls in Lake Michigan.

This paper integrates the known chemical and physical properties of polychlorinated biphenyls (PCB) derived in the laboratory with a mathematical model describing their behavior in Lake Michigan. The conclusion that emerges is that the observed levels of PCB both in Lake Michigan and the fish biomass are consistent with these laboratory measurements. In addition, it is concluded that it will take several years for this ecosystem to cleanse itself of the compounds even if no new input is made. The final sink for PCB is predicted to be degradation in the atmosphere, with some fraction being buried in the underlying sediments of the lake.     

Historical analysis of salmon-derived polychlorinated biphenyls (PCBs) in lake sediments

Several recent studies have highlighted the importance of salmon as a means to deliver biomagnifying contaminants to nursery lakes. There is a lack of studies, however, which demonstrate empirically how this source has varied through time. This is of great significance because past salmon-derived contaminant loading was potentially greater than it is today. By analyzing radiometrically dated sediment cores collected from ten lakes in Alaska and British Columbia (B.C.), we relate historical numbers of sockeye salmon spawners to ΣPCB concentrations and δ¹⁵N values (a paleolimnological proxy for past salmon-derived nitrogen) in the sediments. The results confirm that sockeye salmon have provided an important route for PCBs to enter the lakes in the past, a finding that is especially evident when the data of all lakes are pooled. Significant relationships between sockeye salmon numbers and δ¹⁵N, as well as ΣPCB concentrations and δ¹⁵N in sediments, were also found. However, it is difficult to establish relationships between salmon numbers, ΣPCBs and δ¹⁵N in individual lakes. This may be due to a number of factors which may influence contaminant loadings to the lakes. The factors include: a) changing salmon contaminant loads over time resulting from a lag in the upper ocean reservoir and/or changing salmon feeding locations; b) greater importance of atmospheric transport in lakes with relatively low salmon returns; and c) increased PCB scavenging due to higher algae productivity in the lakes in recent years.     

Background levels of polychlorinated biphenyls in the U.S. population

Background

Polychlorinated biphenyl (PCB) exposures are encountered by the general public by eating contaminated food or living near a previously operating PCB factory or hazardous waste site. PCBs affect the immune, reproductive, nervous, and endocrine systems and are carcinogens. PCBs were banned in the United States in 1977. For public health, it is important to be able to estimate individual risk, especially for vulnerable populations, to monitor the decline in risk over time and to alert the public health community if spikes occur in PCB exposures, by measuring serum PCB levels. The historical decline in PCB exposures cannot be documented within a repeatedly tested general population, since there is no such population. Therefore, our aim was to model serum PCB levels in the US general population over time using published data.

Methods

Models were developed based on 45 publications providing 16,914 background PCB levels in sera collected 1963-2003. Multiple linear regression and exponential decay were used to model the summary PCB levels.

Results

Background levels of higher-chlorinated PCBs (five or more chlorines) in sera increased before 1979 and decreased after 1979; a quadratic model was the best fit. However, the exponential decay model explained better the low PCB serum levels still seen in the general population. For lower-chlorinated serum PCBs, no increase or decrease was shown (1.7 ppb for all years).

Conclusions

Limitations for both models were lack of repeated measures, non-randomly selected study participants, selected years, concentration on geographic areas centered on PCB waste sites, lack of adjustment for BMI or for laboratory methods. Despite the limitations, this analysis shows that background PCB levels in the general population are still of concern. Future work should focus on uncertainties governing how to interpret the levels with respect to possible long term health effects.     

Sedimentation of polychlorinated biphenyls (PCBs) in limnic and marine environments

The sedimentation rates of PCBs in two southern Swedish lakes and a coastal bay in the southern Baltic were determined using sediment traps. The rates were similar at the three locations and ranged from 1.2 to 10.9 μg PCBs m⁻² month⁻¹ during summer. The source for PCBs in sedimenting material is probably the atmosphere. PCB concentrations in sedimenting material were higher than those in surface sediment. This may be due to recirculation of sediment-bound PCBs.The reproducibility of collecting by sediment traps was examined by deploying duplicate traps simultaneously. There were no significant differences in PCB concentration of sedimenting material between traps placed in duplicate. Concentrations of PCBs in the different collecting vessel was similar within one trap.     

Emission of polyaromatic hydrocarbons,polychlorinated biphenyls and polychlorinated dibenzo-p-dioxins and furans from fires of wood chips

An experimental methodology developed by coupling a sampling line based on USEPA method 23 to a standard cone calorimeter is described for the study of uncontrolled emission of pollutants from fires of uncontaminated and contaminated wood. Four different kinds of timber-based materials were studied for target emissions which included PAHs, PCBs and dioxins. The results from the GC/MS analysis have been reported to show the presence of pollutants in emissions from all timber materials studied.     

Determination of dioxins and polychlorinated biphenyls in breast milk, maternal blood and cord blood from residents of Tohoku, Japan

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) are bioaccumulative chemicals that are considered to be toxic contaminants based on several epidemiological studies. To elucidate exposure levels of these chemicals in the present study, concentrations of PCDD/DFs, dioxin-like PCBs (DL-PCBs) and PCBs in breast milk, maternal blood and cord blood obtained from the same participants registered in a birth cohort study in Tohoku, Japan, were measured. Congener-specific analysis revealed several differences in minor congeners of these compounds among the three specimen types, although major congeners were detected in the specimens. The toxicity equivalence quantity concentrations (1998 WHO-TEF) and PCBs in breast milk, maternal blood and cord blood on the whole and on a lipid basis were in the order of breast milk > maternal blood > cord blood. Pearson's correlation coefficients of TEQs and total PCBs among the three specimens were high, with the correlation coefficient of TEQ between breast milk and maternal blood being the highest (r=0.94, p<0.001). On the other hand, the TEQ between breast milk and cord blood was the lowest (r=0.79, p<0.001). Pearson's correlation coefficient between the TEQ and PCBs in each specimen was also high (r=0.82-0.95, p<0.001). The associations of chemical concentrations with maternal age, parity, fish intake, BMI and the rate of body weight increase during pregnancy were analyzed with multiple linear regression analysis. TEQ concentrations and PCBs were negatively associated with parity (p<0.05), and maternal age was positively associated with PCBs (p<0.05). However, the associations with BMI and fish intake during pregnancy were not significant. These results suggest that parity is an important factor affecting the concentrations of dioxins and PCBs in these specimens.     

Distribution of polychlorinated biphenyls in a municipal wastewater treatment plant and environs.

Distribution of polychlorinated biphenyls (PCB) in sewage wastes at a municipal sewage treatment plant was studied, showing that the great bulk of PCBs entering such a treatment plant become adsorbed onto the grit chamber solids and the sludge that is passed from the anaerobic digesters. When appreciable quantities of PCBs are present in sewage, as was the case in this study, significant quantities can nevertheless pass with the effluents discharged from the treatment plant. The PCB concentrations in the treatment plant waters undergoing secondary and tertiary treatment tend to be consistent with the limited solubility properties of the PCBs. However, appreciably higher concentrations can be found in the sediments of waters receiving treatment plant discharges and bioaccumulation in fish is demonstrated readily. Also described are quantitative data on PCBs in soils fertilized with PCB-contaminated sludge.     

Concentrations of polybrominated diphenyl ethers, polychlorinated dibenzo-p-dioxins and dibenzofurans, and polychlorinated biphenyls in human blood samples from Korea

Analysis of blood samples is an effective way of evaluating contamination by persistent pollutants such as polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-p-dioxin/furans (PCDD/Fs), and polychlorinated biphenyls (PCBs) in human population. Concentrations of PBDEs, PCDD/Fs and PCBs were measured in the blood of laborers (n = 13) working full time in two different municipal waste incinerator (MWI) plants and residents from the general population (n = 22) living in areas near MWIs in Korea. The concentrations of PBDEs were found to be slightly higher in the blood of incineration workers (8.61-46.05 ng/g lipid; mean, 19.33 ng/g lipid; median, 15.94 ng/g lipid) in comparison to that of residents from the general population (7.24-28.89 ng/g lipid; mean, 15.06 ng/g lipid; median, 14.34 ng/g lipid). The total average PCDD/Fs and PCB TEQ concentration was 20.11 pg/g lipid, averaged over incineration workers (17.73 pg/g lipid) and the general population (21.52 pg/g lipid). In addition, the average total crude concentration of PCDD/Fs was 7.40 ng/g lipids, which was 4.1 times greater than for PBDEs. Congener specific analysis confirmed that BDE 47 was a predictive indicator for total PBDE concentration (correlation coefficient r = 0.912), and that PCB 153 was a predictive indicator for total PCB concentration (r = 0.967). The PBDE levels in human blood in Korea are much higher than those reported in other countries. The presence of the BDE 183 congener was characteristic in the blood of workers from an electronic dismantling facility in MWIs.     

Acute non-cancer mortality excess after polychlorinated biphenyls and polychlorinated dibenzofurans mixed exposure from contaminated rice oil: Yusho

In Japan in 1968, rice-oil contaminated by polychlorinated biphenyls and polychlorinated dibenzofurans caused severe food poisoning, termed “Yusho” (oil disease). Several previous studies attempted to evaluate the effects targeting officially-certified Yusho patients. However, these studies have several limitations such as the left-truncated nature of the registry or residual confounding arising from the referent population selection. We thus conducted an area-based standardized mortality ratios (SMRs) study using vital statistics. A severely affected area (Tamanoura area) was adopted as the exposure group, with a reference population from Nagasaki prefecture in Kyushu, which included the Tamanoura. A large number of residents in Tamanoura were exposed to the rice-oil (28% of all the certified cases as of 2009). We estimated SMRs of non-cancer and cancer diseases for the years 1968-2002. Shortly after the exposure, SMRs of all causes, diabetes mellitus, cardiovascular disease, pneumonia/bronchitis, and bronchus/lung cancer were elevated. In particular, SMRs of heart disease were 1.97 [95% confidence intervals (CI): 1.09-3.56] in 1968, 2.05 (95% CI: 1.16-3.60) in 1969, and 1.89 (95% CI: 1.05-3.41) in 1975. However, we did not observe clear increase in SMRs more than 10 years after the exposure. This study provides further evidence in Yusho, especially on acute effects on non-cancer mortality.     

The influence of a capacitor plant in Serpukhov on vegetable contamination by polychlorinated biphenyls

PCB content in soil and vegetables grown on the polluted soils in some districts of the town of Serpukhov have been studied for 10 years after the use of PCBs had been banned at the local capacitor plant. Soil contamination with PCBs in the vicinity of the plant is still extremely high (up to 30 mg/kg). Vegetables grown on the polluted soils, especially carrots and green parts of fennel, parsley, celery are also highly contaminated. The primary pollutants are found to be tri- and tetrachlorobiphenyls (up to 70-80% of total PCBs).     

Polychlorinated naphthalenes,polychlorinated biphenyls and ΣDDT residues in British birds of prey

Tissue samples (muscle, liver and kidney) from small raptors (kestrels) have been extracted by steam extraction into hexane and the levels of ΣDDT, PCB, PCN and PCT determined by carbon skeleton-gas chromatography. A 3% palladium catalyst, and a 2% RbCl salt column coupled to a mass spectrometer were used for the determination. Significant quantities of ΣDDT and PCBs were found in all samples. Only trace amounts of PCTs were found. The relative concentrations of ΣDDT and PCB may be rationalised with the environment from which the sample was taken.     

Polybrominated diphenyl ethers and polychlorinated biphenyls in indoor dust in Durban,South Africa

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in indoor dust of three microenvironments in Durban, South Africa. The sum of eight PBDEs and three PCBs were quantified by gas chromatography with mass spectral detection. The mean concentrations of ∑_n = 8 PBDEs and ∑_n = 3 PCBs in 10 homes, 11 offices, and 13 university students’ computer laboratories were 1710, 1520, and 818 ng/g, and 891, 923, and 1880 ng/g for PBDEs and PCBs, respectively. The concentration of PCBs found in homes was independent (P = 0.0625) of building construction year. Similarly, no relationship was observed between PCB concentrations and floor type. The concentrations of PBDEs correlated (r = 0.60) with PCB concentrations in homes, thus assuming similar sources. The elevated concentrations of PBDEs and PCBs may have significant implications for human exposure.     

Identification of subwatershed sources for chlorinated pesticides and polychlorinated biphenyls in the Ballona Creek watershed

Santa Monica Bay forms part of the western border of the greater Los Angeles region. The Ballona Creek watershed is highly urbanized and past studies indicate that Ballona Creek is the largest source for most pollutants to Santa Monica Bay. This study evaluates the contribution of subwatersheds to PCB and chlorinated pesticide loading during wet weather flow. Fifteen storm drains from these subwatersheds were sampled during three storms during the 2005-2006 winter rainy season. A series of grab samples were taken over the duration of the storms. The suspended solids were analyzed for polychlorinated biphenyls (PCBs) and chlorinated pesticides. A geographic information system (GIS) was used to calculate the runoff volume from each subwatershed to estimate pollution mass loading. There was no statistical difference among subswatersheds; however, a disproportionate mass of PCB loading came from site 5, which had no obvious sources. No specific subwatersheds were identified as key sources for chlorinated pesticides. These results may serve as a model for other locations with concerns for historic PCB and chlorinated pesticides loadings.     

Distribution of polychlorinated biphenyls in marine species from French Frigate Shoals, North Pacific Ocean

Polychlorinated biphenyls (PCBs) were analyzed in: sediment; coral (Porites evermanni); fish (Stegastes fasciolatus, Neoniphon sammara, Acanthurus triostegus and Mulloidichthys vanicolensis); crab (Grapsus tenuicrustatus); lobster (Panulirus marginatus); and eel (Conger cinereus, Gymnothoraxflavimarginatus, G. undulatus and G. meleagris) samples collected from Tern Island and the corresponding reference samples from Disappearing Island. The two islands are part of French Frigate Shoals, a national wildlife refuge in the North Pacific Ocean. The dominant congeners 118, 138 and 153 represent 22-25, 32-34, 12-39, 37-46 and 30-55% of the sum of PCBs in the coral, sediment, fish, crab and eel, respectively. In general, high trophic species such as eels were found to highly bioaccumulate PCBs. The total average PCB concentrations were as high as 96 and 29 microg/g dry wt. in eels and damselfish, respectively, from Tern Island. The localized behavior and high bioaccumulation potential for PCBs suggest that damselfish are an excellent species for monitoring PCBs in small areas in the ocean. The high average concentrations of the sum of PCBs in different food chain levels suggest that pollution source(s) are around Tern Island and possibly around Disappearing Island. Aroclor 1254 and its analogs are suspected sources responsible for PCBs in the samples.