PCBs in Passaic River Sediments: Some Analytical Considerations

BackgroundPCB contamination in the built environment may result from the release of PCBs from building materials. The significance of this contamination as a pathway of human exposure is not well-characterized, however. This research compared the serum PCB concentrations, and congener profiles between 18 teachers in PCB-containing schools and referent populations.MethodsBlood samples from 18 teachers in PCB-containing schools were analyzed for 57 PCB congeners. Serum PCB concentrations and congener patterns were compared between the teachers, to the 2003-4 NHANES (National Health and Nutrition Examination Survey) data, and to data from 358 Greater Boston area men.ResultsTeachers at one school had higher levels of lighter (PCB 6-74) congeners compared to teachers from other schools. PCB congener 47 contributed substantially to these elevated levels. Older teachers (ages 50-64) from all schools had higher total (sum of 33 congeners) serum PCB concentrations than age-comparable NHANES reference values. Comparing the teachers to the referent population of men from the Greater Boston area (all under age 51), no difference in total serum PCB levels was observed between the referents and teachers up to 50 years age. However, the teachers had significantly elevated serum concentrations of lighter congeners (PCB 6-74). This difference was confirmed by comparing the congener-specific ratios between groups, and principal component analysis showed that the relative contribution of lighter congeners differed between the teachers and the referents.ConclusionsThese findings suggest that the teachers in the PCB-containing buildings had higher serum levels of lighter PCB congeners (PCB 6-74) than the referent populations. Examination of the patterns, as well as concentrations of individual PCB congeners in serum is essential to investigating the contributions from potential environmental sources of PCB exposure.

Comparative levels of organochlorine compounds in flounders from the northeast coast of Newfoundland and an offshore site

PCB congener accumulation in biota and sediments involves several processes, including physical factors characterized by octanol-water partition coefficients and water solubility, and chemical factors which are influenced by the degree of chlorination and the substitution pattern of the individual congeners. The present study was conducted to determine if PCB congeners are distributed in a consistent pattern in two lakes known to have received point-source contamination with PCBs, and a control lake with no known point source. Samples of 4 groups of biota, water and sediment indicated that each lake had a unique pattern of congener distribution which was probably related to the source of the contamination. A comparison of total and individual PCB congener concentrations within each study lake showed that no one species consistently contained the highest residues of PCBs. Smallmouth bass had the highest concentration of PCBs in Rice lake while yellow perch was highest in Lakes Clear and Scugog. Sediments contained lower concentrations of PCBs than biota and did not show enrichment of higher chlorinated congeners, despite having high organic carbon content. Within the contaminated lakes, young-of-the-year (YOY) and older yellow perch had the same congener pattern, and there was no significant difference in their PCB concentration. This indicates that equilibrium concentrations of PCBs are established rapidly in the young fish and that all congeners equilibrate at the same rate.

A food web bioaccumulation model was used to hindcast PCB congener concentrations in aquatic biota from western Lake Erie in the years prior to the zebra mussel invasion, and these results were compared to post-mussel predicted concentrations that had been verified previously against measured data to estimate the effects of mussels on the trophodynamics of PCB congeners in western Lake Erie. Two hindcasting scenarios were compared to a third, previously verified, scenario to determine the changes in PCB congener concentrations in biota in response to (i) modifications to food web structure, before and after the introduction of mussels, and (ii) modifications to food web structure combined with a decline in particulate organic carbon (POC) concentrations resulting from removal of seston from the water column by mussel filtering activities. The reduction in the concentration of POC, attributed to the prodigious filter-feeding of large zebra mussel populations, was predicted to have caused increases in the freely dissolved concentrations of PCB congeners ranging from 2.9% to 9.3%. These increases in dissolved chemical were predicted by the model to cause small increases (range 0−7.3%) in the PCB congener burdens of many biota including zooplankton, prey fish species, and walleye. Other organisms, such as Gammarus, small white suckers, and freshwater drum, were predicted to have larger increases in their PCB body burdens (9.1−22.2%) as a result of the increase in freely dissolved chemical and a shift in diet. For crayfish, yellow perch, black crappie, white perch, large white suckers, gizzard shad, and largemouth bass, the increased exposure to chemical via water was offset by decreased chemical exposure via the diet, which resulted from shifts in diet toward less contaminated items brought about by the presense of zebra mussels. The results of this study are relevant to Lake Erie resource managers that are concerned about the potential of zebra mussels to alter PCB congener dynamics in the western basin.

Relative aryl hydrocarbon hydroxylase (AHH) induction potencies of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the two coplanar PCB congeners 3,3′,4,4′-tetrachlorobiphenyl (IUPAC congener 77) and 3,3′,4,4′,5-pentachlorobiphenyl (IUPAC congener 126) were determined in rainbow trout (Oncorhynchus mykiss). Trout were injected intraperitoneally with chemicals dissolved in corn oil. The ED50 for AHH induction in TCDD-injected fish was 0.005 μmol/kg. The ED50s for PCB congeners 126 and 77 were 1.0 μmol/kg and 2.2 μmol/kg, respectively. AHH toxic equivalent factors (AHH-TEFs), or TCDD equivalents, were determined as the ratio of the TCDD ED50 to the ED50 for each PCB congener. AHH-TEFs for congeners 126 and 77 were 0.005 and 0.002, respectively. Toxic equivalent quantities for AHH induction (AHH-TEQs) were calculated by multiplying the TCDD equivalent for each chemical by its concentration in fish at environmental levels. AHH-TEQs, based on whole-body TCDD and PCB concentrations in Lake Ontario rainbow trout, were two- to threefold greater for the coplanar PCBs than for TCDD. Although these data do not necessarily indicate that coplanar PCBs are highly toxic to fish, the results indicate that these compounds have the potential to contribute to the environmental effects of compounds structurally related to TCDD.

PCBQ: Computerized quantification of total PCB and congeners in environmental samples

BackgroundThe presence of PCB in caulking (sealant) material found in masonry buildings has been well-documented in several countries. A recent investigation of 24 buildings in the greater Boston area found that 8 buildings had high PCB levels in caulking materials used around window frames and in joints between masonry blocks. Workers removing caulking material have been shown to have elevated serum PCB levels.MethodsThis project compared serum PCB levels among male workers who installed and/or removed PCB-containing caulking material from buildings in the greater Boston area with reference serum PCB levels from 358 men from the same area. Serum PCB levels were measured in the same laboratory by liquid-liquid extraction, column chromatography clean-up and dual capillary column GC/microECD analysis.ResultsWhen the congener profiles were compared between the reference population and the construction workers, the serum levels of the more volatile, lighter PCBs (di-, tri-and tetrachloro, sum of IUPAC# 6–74) were substantially higher among the construction workers. One of the youngest workers had the lowest total serum PCB levels (sum of 57 congeners) of all 6 workers, but the contribution of more volatile (less chlorinated) PCB congeners (#16, 26,28,33,74,66, and 60) was markedly higher than in other 5 workers and reference men. Only this worker was working on a job that involved removing PCB caulking at the time of the blood sampling.ConclusionWhile the results of this pilot study are based upon small numbers (6 construction workers who handled PCB caulking), the serum PCB levels among the construction workers exceed the referents. Comparison of the congener profiles suggests that there are substantial differences between the construction workers and the general population samples. These differences, and the similarities of profiles among the construction workers strongly suggest that occupational contact with caulking material can be a major source of PCB exposure for construction workers.

We used the multimedia chemical fate model BETR Global to evaluate changes in the global distribution of two polychlorinated biphenyls, PCB 28 and PCB 153, under the influence of climate change. This was achieved by defining two climate scenarios based on results from a general circulation model, one scenario representing the last twenty years of the 20th century (20CE scenario) and another representing the global climate under the assumption of strong future greenhouse gas emissions (A2 scenario). The two climate scenarios are defined by four groups of environmental parameters: (1) temperature in the planetary boundary layer and the free atmosphere, (2) wind speeds and directions in the atmosphere, (3) current velocities and directions in the surface mixed layer of the oceans, and (4) rate and geographical pattern of precipitation. As a fifth parameter in our scenarios, we considerthe effect of temperature on primary volatilization emissions of PCBs. Comparison of dynamic model results using environmental parameters from the 20CE scenario against historical long-term monitoring data of concentrations of PCB 28 and PCB 153 in air from 16 different sites shows satisfactory agreement between modeled and measured PCBs concentrations. The 20CE scenario and A2 scenario were compared using steady-state calculations and assuming the same source characteristics of PCBs. Temperature differences between the two scenarios is the dominant factor that determines the difference in PCB concentrations in air. The higher temperatures in the A2 scenario drive increased primary and secondary volatilization emissions of PCBs, and enhance transport from temperate regions to the Arctic. The largest relative increase in concentrations of both PCB congeners in air under the A2 scenario occurs in the high Arctic and the remote Pacific Ocean. Generally, higher wind speeds under the A2 scenario result in more efficient intercontinental transport of PCB 28 and PCB 153 compared to the 20CE scenario. Our modeling indicates that in a future impacted by climate change, we can expectincreased volatilization emissions and increased mobility of persistent organic pollutants with properties similar to those of PCBs.

Bioavailability of 2,3,7,8-TCDD, 2,3,7,8-TCDF and PCBs to marine benthos from Passaic River sediments

A bioenergetics-based model was used to simulate the accumulation of total PCBs and 20 PCB congeners by nestling tree swallows at two contaminated sites on the Upper Hudson River, New York. PCB concentrations in birds were calculated as the sum of inherited residues and those acquired through consumption of contaminated insects. Close agreement between simulations and measured residues in 5-, 10-, and 15-day-old nestlings was obtained when PCB concentrations in the diet were set equal to those in food boli taken from adult birds. These simulations were further optimized by fitting the value of a dietary assimilation efficiency constant. Fitted constants for both sites were similar and averaged about 0.7. An evaluation of model performance for individual congeners provided no evidence of metabolic biotransformation. The results of this study are consistent with a companion effort in which principal components analysis was used to compare PCB congener patterns in insects and in tree swallow eggs, nestlings, and adults. Together, these studies establish a quantitative linkage between nestling tree swallows and the insects that they consume and provide strong support for the use of nestling swallows as a biomonitoring species for exposure assessment.

Comparison of PCB Congeners and Pesticide Levels between Serum and Milk from Lactating Women

Long-term trends in mercury and PCB congener concentrations in gannet (Morus bassanus) eggs in Britain

Biological treatment of transformer oil using commercial mixtures of microorganisms

Serum concentrations of indicator PCB congeners in the Czech adult population

Chemometric analysis of potential sources of polychlorinated dibenzo-p-dioxins and dibenzofurans in surficial sediments from Newark Bay, New Jersey