Skin Absorption and Damage from PCBs

Skin Absorption and Damage from PCBs

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Evidence that PCBs are Absorbed Through the Skin

This is not a complete list of all studies on this topic. For more studies, visit the TOXNET database operated by the National Library of Medicine (the source of these abstracts).

Study #1

six brands of carbonless copy paper still contained significant PCBs, as of 1990
PCBs stuck to the fingers of people handling the paper
washing removed only 1/3 of the PCBs

Non-carbon copying paper was examined for polychlorinated biphenyl (PCB) content. Four brands of Japanese copying paper, one British, and two American copying papers were investigated. Each copying paper consisted of a set of three sheets of paper. The sheets were separately extracted with acetone for 3 days. Extracts were examined using gas chromatography. The amount of PCB sticking to the fingers by handling the copying papers was also estimated. Ninety six sets of papers (each with three sheets) were counted sheet by sheet turning each one over with the fingers. Fingers were washed with n-hexane before or after washing with soap and water and the resulting n-hexane washings were examined for PCBs. Gas chromatographic patterns observed with all brands of paper were identical to that of Kanechlor-300, a brand of PCB. The approximate concentration of PCB was 2 to 6 percent in the upper and middle sheets and 0.02 percent in the lower sheets. PCB obtained from finger washings ranged from 11.40 to 51.68 micrograms in five subjects. Washing with soap and water removed only about 33 percent of PCB. The authors conclude that common non-carbon copying papers contain substantial amounts of PCB which easily sticks to the fingers when the paper is handled. The use of PCB for this sort of paper should be discontinued in all countries. (Kuratsune et al, 1990)

Study #2

PCBs can be rapidly and excessively absorbed through the skin
monkeys absorbed 17.3 to 33.9% of less concentrated PCBs
monkeys absorbed 15.2 to 19.4% of higher concentrated PCBs
guinea pigs absorbed 33.2 to 55.6% of PCBs

The dermal absorption, systemic elimination, and dermal wash efficiency for polychlorinated-biphenyls (PCB) were determined in rhesus monkeys and guinea pigs. Monkeys were placed in metabolic chairs for 24 hours after application of a solution containing 42 percent carbon-14 labeled PCB spread over abdominal skin. Animals were then transferred to metabolic cages. Monkeys were given intramuscular (im) injections of 50 microliters of labeled 42 percent PCB solution. Urine and feces were collected for 28 days after PCB treatment. Guinea-pigs received topical applications of labeled 42 percent PCB spread over skin on the back of ears. Guinea-pigs were given im thigh injections of solutions containing 54 or 42 percent labeled PCB. Daily urine and feces samples were collected for 12 days. Some animals received both dermal and injected doses, and urine and feces were collected for 15 days. Carbon-14 content of urine and feces was analyzed by liquid scintillation spectrometry. Disposition of radioactivity after parenteral administration to monkeys over the 30 day period was 43.4 percent in urine and 22.4 percent in feces. In guinea-pigs given 42 percent PCB, 32.3 percent was excreted in urine and 20.0 percent in feces; with 54 percent, 46.6 percent was excreted in feces and 14.9 percent in urine. A steady, continual elimination of radioactivity was seen in both species and doses. Dermal absorption in monkeys was 17.3 and 33.9 percent in two animals given 4.1 micrograms per square centimeter (microg/cm2), and 15.2 and 19.4 percent in two animals given applications 4.7 times greater. In guinea-pigs, 33.2 percent of the 4.6microg/cm2 dose of 42 percent PCB was absorbed, compared with 55.6 percent of the 5.2microg/cm2 application of 54 percent PCB. The authors conclude that PCBs can be rapidly and excessively absorbed through the skin, are distributed through the body, and are slowly eliminated. (Wester et al, 1983)

Study #3

100% of lower chlorinated PCBs were absorbed in 48 hours, compared to 30% of high chlorinated
lower chlorinated PCBs are rapidly absorbed, then metabolized and eliminated from the body
higher chlorinated PCBs are absorbed more slowly, but stay and accumulate in the body

The fate of selected mono-, di-, tetra-, and hexachlorobiphenyls was investigated following single dermal administration (0.4 mg/kg) to determine the effects of chlorine substitution on the dermal absorption and disposition of polychlorinated biphenyls (PCBs). Single dermal doses of 14C-labeled mono-, di-, tetra-, and hexachlorobiphenyls were administered to 1-cm2 areas on the backs of F-344 male rats. Unabsorbed radioactivity was removed from the dose site either at euthanasia or 48 h postdose. Distribution of radioactivity in the dose site and selected tissues was determined by serial sacrifice at time points up to 2 weeks. Dermal penetration varied inversely with degree of chlorination and at 48 h ranged from ca. 100% for monochlorobiphenyl to ca. 30% for the hexachlorobiphenyl. Penetration rate constants correlated well with log Kow. PCBs were retained in the epidermis for up to 2 weeks postdose. The data from these studies suggest that systemic absorption of PCBs involves a combination of sequential processes including penetration across the stratum corneum, possibly metabolism in the epidermis and/or dermis, adsorption to proteins, and finally absorption into the systemic circulation. The skin favors the rapid absorption of less chlorinated PCBs, but the relatively rapid metabolism and elimination of these compounds would result in lower body burdens. More highly chlorinated PCBs penetrate less rapidly but remain in the site of exposure and slowly enter the systemic circulation. The dermal absorption of a commercial PCB mixture was modeled, and the results suggest that the net result of the differences in absorbance rates would be a greater body burden of higher chlorinated PCBs relative to those that have a lower chlorine content. (Garner et al, 1998)

Study #4

skin absorption rates are similar in humans, pigs and rhesus monkeys
absorption rates for rabbit and rat were significantly greater than man

The percutaneous absorption of industrial solvents was reviewed with regard to the mechanisms, parameters, and clinical representation of percutaneous absorption in humans. The advantages and limitations of determining absorption by the in-vitro diffusion cell method and the in-vivo analysis of biologic fluids and tissues were compared. The in-vitro method was preferred for the comparison of the relative absorption of many compounds or the relative absorption of one compound under varied conditions. In-vitro prediction of in-vivo absorption was not demonstrated. In-vivo studies in humans were determined most sensitive for assessing the specific absorption of an agent in man. Comparative studies of percutaneous absorption using monkeys, rabbits, rats, swine, and man indicated that percutaneous absorption rates in the pig and rhesus-monkey were similar to man whereas the absorption rates for rabbit and rat were significantly greater than man. The parameters affecting percutaneous absorption were the dose concentration and the surface area exposed, the skin location of application, occlusion, the skin condition, the vehicle and the use of multiple doses, and metabolism. The analysis of percutaneous absorption in determination of the toxicity of polychlorinated-biphenyls and the relationship between the dermal bioavailability of hydrocortisone and the incidence of epidermal tumors were included in the discussion. (Wester et al, 1987)

Study #5

dermal absorption is a major route for PCBs entering the body
soap and water is a suitable system for removing PCBs from contaminated ski

The percutaneous absorption and skin decontamination of polychlorinated biphenyls (PCBs) were studied in-vitro and in-vivo. Adult female Rhesus-monkeys were administered carbon-14 (C-14) labeled aroclor-1242 (53469219) or aroclor-1254 (11097691) intravenously (iv) or topically. In the topical experiment the aroclors were administered in mineral-oil or trichlorobenzene. Urine and feces samples were collected for 30 days and assayed for C-14 activity. The amounts of aroclor-1242 and aroclor-1254 absorbed were calculated from the data. Human cadaver skin samples that had been dermatomed to 0.25 to 0.30 micron thickness and mounted on continuous flow diffusion cells were treated with C-14 labeled aroclor-1242 or aroclor-1254 applied in mineral-oil or trichlorobenzene. The extent of skin absorption was determined by measuring the amount of C-14 label appearing in the receptor fluid after 17 hours. Powdered human stratum corneum was treated with radiolabeled aroclor-1242 in mineral-oil or trichlorobenzene. The samples were treated with soap and water, mineral-oil, or ethanol at various times for up to 8 hours to assess their ability to remove aroclor-1242. Monkeys were administered labeled aroclor-1242 in mineral-oil or trichlorobenzene topically. The application sites were washed with soap and water, mineral-oil, or ethanol at various times up to 24 hours later. In-vivo, the amounts of aroclor-1242 absorbed after iv injection and topical application in mineral-oil and trichlorobenzene were 55.5, 11.3, and 10.0%, respectively. The corresponding percentages for aroclor-1254 were 26.7, 5.5, and 3.9%, respectively. Less than 1% of the applied doses were absorbed in-vitro. Ethanol was the most effective in removing aroclor-1242 from human stratum corneum, followed by mineral-oil, soap and water, and water, in that order. In-vivo, soap and water, trichlorobenzene, and mineral-oil were able to remove all of the aroclor-1242 with five washes. Ethanol removed only 63% of the dose after five washes. The authors conclude that dermal absorption is a major route for PCBs entering the body. Soap and water is a suitable system for removing PCBs from contaminated skin. (Wester et al, 1990)

Study #6

PCBs can easily partition from soil into skin and be absorbed by the body.
The largest amounts of PCBs were absorbed by human skin from contaminated water samples compared with the amounts absorbed from soil and mineral-oil
13.8 to 14.1% of the PCBs were absorbed through the skin

Polychlorinated biphenyls (PCBs) are ubiquitous and persistent environmental pollutants. The major resident site for these PCBs is the soil, and human skin is frequently in contact with soil. Our objective was to determine the percutaneous absorption of the PCBs Aroclor 1242 and Aroclor 1254 from soil. Rhesus-monkeys were treated topically with soil samples contaminated with 44 parts per million (ppm) Aroclor-1242 (53469219) or 23ppm Aroclor-1254 (11097691) for 24 hours, and the urine and feces were monitored for the presence of PCBs. PCB concentrations on skin were 1.75 micrograms/cm2 for Aroclor 1242 and 0.91 microgram/cm2 for Aroclor 1254. In vivo percutaneous absorption in the rhesus monkey was determined by urinary and fecal [14C]-PCB excretion for a 5-wk period following topical dosing. For comparison purposes, human skin samples were exposed in-vitro to contaminated soil, mineral-oil, or water in diffusion cells for 24 hours, washed, and assayed for PCB absorption. Powdered human stratum corneum samples were used to determine the binding behavior of the PCBs. The total urinary excretion of Aroclor-1242 was 4.1% of the dose and the total fecal excretion was 3.6% of the dose while for Aroclor-1254 the totals were 3.4% and 0.42%, respectively. Based on published data on the excretion of these compounds following intravenous administration, the in-vivo percutaneous absorption for Aroclor-1242 was calculated to be 13.8+/- 2.7 (SD)% of the dose and 14.1+/- 1.0% of the dose for Aroclor-1254. These absorption amounts are similar to the absorption of Aroclor 1242 and 1254 from other vehicles. The largest amounts of PCBs were absorbed by the human skin samples from contaminated water samples compared with the amounts absorbed from soil and mineral-oil samples. Calculation of partition coefficients of the PCBs following incubations with powdered stratum corneum demonstrated that the PCBs easily partitioned from water and soil into stratum corneum while the mineral-oil tended to retain the PCBs. Stratum corneum had a greater affinity for the PCBs than did the soil. The authors conclude that PCBs can easily partition from soil into skin and be absorbed by the body. (Wester et al, 1993)

Study #7

children were considered at greatest risk from PCB contaminated soil through soil ingestion or skin contact

In 1985, the human exposure from a site of PCB (Aroclor 1260) contamination in a Toronto community was assessed. The primary source of potential exposure was soil. Extensive surface soil sampling revealed levels greater than expected (geometric mean level = 0.19 ppm). Children under age 6 were considered to be at greatest risk of exposure as they may absorb PCBs from ingested soil or skin contact. A sample of 30 children aged 1-5 was recruited from the community and 23 from a socio-demographically similar control area that had significantly lower but detectable soil PCB levels (geometric mean level = 0.12 ppm). Exposure to PCBs from breastfeeding, food consumption, contact with soil, and parental occupation was comparable in the two groups. Geometric mean blood PCB levels did not differ significantly between the study (1.5 ppb) and control (1.9 ppb) group. Levels ranged up to 5 ppb in both groups and are comparable to those described in children elsewhere in North America. (Yaffe et al, 1989)

Study #8

the dermal route is the predominant contributor to PCB body burden

Evidence that dermal absorption of polychlorinated biphenyls (PCB) (Aroclor-1254 (11097691) and Aroclor-1260 (11096825)) was the major route to PCB body burdens in transformer maintenance and repair personnel was presented. Air samples were collected in Florisil tubes and analyzed according to the NIOSH Standard Method P-and CAM 244 (NSM). Wipe samples were collected from areas of 100 square centimeters on work surfaces observed to be contacted frequently by switchgear workers. The area was wiped with a Whatman Smear Tab saturated with reagent grade methanol. Smear Tabs were extracted with reagent grade hexane and analyzed according to NSM. Work practices of the switchgear operators were watched closely to observe primary and secondary dermal exposures. The results of air sampling showed that during the 4 to 8 hour operation, 70 percent of measured exposures were below 1 microgram/cubic meter as an 8 hour time weighted average (TWA). More than 90 percent of the surface samples showed measurable PCB contamination ranging from 0.007 to 1.075 micrograms/square centimeter. Two types of dermal exposure were observed. In the primary exposure, workers were contaminated through contact with transformer parts or tools. The secondary exposure was through contact with contaminated surfaces remote from the job site. A calculation, based on the assumption that a worker had a single contact with one drop of transformer oil that was 100 percent absorbed, indicated a daily dermal absorption of 54,000 micrograms (microg) PCB. The value calculated for inhalation exposure was 8.0microg per day, derived by assuming 1microg PCB vapor/cubic meter. The authors conclude that exposure to PCBs by the dermal route is the predominant contributor to body burden. In conclusion, the authors state that standards designed to prevent skin contact with PCBs and prescribing limits for surface contamination of PCBs should be developed. (Lees et al, 1987)

Study #9

due to the transport of PCBs on dust particles, the current primary route of exposure of most of the population to PCBs is dermal
less chlorinated types of PCBs are much more bioavailable than the more highly chlorinated congeners.

The production and use of polychlorinated biphenyls (PCBs) has been banned in the US for over 20 years. However, due to their extreme persistence in the environment, their insolubility in water, and their adsorption onto soil particles, environmental and human exposure continues to be a matter of concern. It is speculated that, due to the transport of PCBs on dust particles, the current primary route of exposure of most of the population to PCBs is dermal. Studies of the dermal absorption of PCBs have established that bioavailability following dermal exposure is highly dependent upon the degree and position of chlorination. The less chlorinated congeners are much more bioavailable than the more highly chlorinated congeners. Within a group, e.g., tetrachlorobiphenyls, bioavailability varies with the position of chlorination. Those congeners having chlorine atoms in the para position are less readily absorbed from the skin. Data developed in this work have been used to construct a model that predicts the fate of the complex mixtures of PCBs found in the environment. In the course of these studies an additional line of research was developed to address the estrogenicity of catechol metabolites of PCBs. When cultured HeLa cells transfected with the estrogen report er gene ERET81CAT were incubated with PCB catechols the responses elicited fell within the range of effects measured for other environmental estrogens, e.g., nonylphenol and o,p-DDT. Again, structural considerations play a major role in the biological effects of the respective metabolites. Whereas 2,4-catechols showed virtually no activity the activity of the 3,4-catechols increased with the degree of chlorination. In support of these studies, methods were developed for the synthesis of PCB catechols in quantities sufficient for more extensive studies. Studies of the effect of these synthetic metabolites in in vitro systems demonstrated that PCB catechols are potent inhibitors of catechol O-methyltransferase ( COMT). This is of particular relevance because it is this enzyme that inactivate s the active metabolites of estrogen, 2- and 4-hydroxyestradiol. Inhibition of inactivation should result in a secondary estrogenic response as a result of the prolongation of the action of endogenously formed estrogen. Thus, demonstration of the potent inhibition of estrogen metabolism by their catechol metabolites may explain the estrogenic effects reported for PCBs. - polychlorinated biphenyls (PCBs), kinetic models, phenolphthalein, dermal absorption, environmental estrogens, catechols (incomplete abstract) (Matthews, NIOSH)

Study #10

PCBs passed through PVC gloves, resulting in dermal PCB exposure for workers

This study measured the permeation of polychlorinated-biphenyls (1336363) (PCBs) through polyvinyl-chloride (PVC) gloves used by workers at a facility for recovery of PCBs. The goal was to assess whether PVC gloves give adequate protection from PCBs. The workers were instructed to wash their hands thoroughly and then to put on the PVC glove with a cotton glove underneath. The gloves were removed carefully after the worker performed a task. The PCB content of the cotton glove was then assayed by a standard Environmental Protection Agency method to assess the amount permeating through the PVC glove and reaching the skin. The mass of PCBs in micrograms was measured in 12 samples from employees doing tasks for 20 to 70 minutes while wearing PVC gloves. Dermal exposures of employees ranged from 14 to 61 micrograms during 45 to 50 minutes of transformer pumping, 7 to 102 micrograms during 20 to 25 minutes of stabilization, and 70 to 353 micrograms during 30 to 40 minutes of drum pumping. Dermal exposures were 2 to 8 micrograms for a researcher who performed similar tasks for similar times and washed his hands thoroughly. The employees' dermal exposure was compared to an inhalation PCB dose of 9,600 micrograms, based on 480 minutes of breathing at 20 liters/minute and an inhalation threshold limit value of 1mg/m3. The authors concluded that the PCB gloves can be used safely, since the dermal exposure to PCBs through PVC gloves in this study was well below the maximum dose considered safe, and that good hygiene should be encouraged. (Perkins et al, 1989)

Study #11

dermal PCB contact estimates vary depending on the type and duration of the surface wipe

Health risks posed by dermal contact with PCB-contaminated porous surfaces have not been directly demonstrated and are difficult to estimate indirectly. Surface contamination by organic compounds is commonly assessed by collecting wipe samples with hexane as the solvent. However, for porous surfaces, hexane wipe characterization is of limited direct use when estimating potential human exposure. Particularly for porous surfaces, the relationship between the amount of organic material collected by hexane and the amount actually picked up by, for example, a person's hand touch is unknown. To better mimic PCB pickup by casual hand contact with contaminated concrete surfaces, we used alternate solvents and wipe application methods that more closely mimic casual dermal contact. Our sampling results were compared to PCB pickup using hexane-wetted wipes and the standard rubbing protocol. Dry and oil-wetted wipe samples, applied without rubbing, picked up less than 1% of the PCB picked up by the standard hexane procedure; with rubbing, they picked up about 2%. Without rubbing, saline-wetted wipes picked up 2.5%; with rubbing, they picked up about 12%. While the nature of dermal contact with a contaminated surface cannot be perfectly reproduced with a wipe sample, our results with alternate wiping solvents and rubbing methods more closely mimic hand contact than the standard hexane wipe protocol. The relative pickup estimates presented in this paper can be used in conjunction with site-specific PCB hexane wipe results to estimate dermal pickup rates at sites with PCB-contaminated concrete. (Slayton et al, 1998)

Study #12

dermal absorption of PCBs is generally the route of entry into the bodies of exposed workers.

Human occupational exposure to polychlorinated biphenyls (PCBs) is discussed. Dermal absorption of PCBs is generally the route of entry into the bodies of exposed workers. The magnitude of human occupational exposure has been evaluated by measurement of blood and adipose tissue concentrations of PCBs. For lower chlorinated PCBs (low PCBs), a range of concentrations from 100 to 1,000 nanograms per milliliter (ng/ml) has been reported in plasma. Adipose concentrations of low PCBs range from 15 to 44 micrograms per gram, and there is a strong correlation between adipose and plasma concentrations of low PCBs. The average plasma concentration of higher PCBs such as Aroclor-1254 (11097691) is 86ng/ml in exposed workers, and adipose and plasma higher PCB concentrations correlate significantly. These values are 10 to 1,000 times those observed in persons not occupationally exposed to PCBs. Blood concentrations of higher PCBs correlate with duration of employment and age among occupationally exposed workers. The differentiation of PCB congeners in humans, compared with the commercial product, is difficult because there is no widely accepted means of objectively designating PCB patterns in human samples. The problem is particularly difficult with mixed occupational exposures. Discrimination of PCB congeners in human samples may require standardization of specific sample preparation techniques and verification by gas chromatography and mass spectrometry. (Wolff, 1985)

Study #13

dermal contact may have contributed to elevated PCB levels in workers

Polychlorinated-biphenyl (1336363) (PCB) levels were determined in workers exposed to contaminated work surfaces. A transformer manufacturing company which used PCBs extensively had sold the site to a machine shop company which used no PCBs in any process; PCB contamination of the site was discovered 3 years later. None of the company's 55 employees had a history of occupational PCB exposure or clinical or biochemical signs of PCB intoxication. Mean serum PCB levels were 14.4 parts/billion (ppb) in 38 production workers (all men) and 4.8 ppb in 17 office workers (8 men, 9 women). Serum PCB levels in the office workers were slightly higher in the men, but the sex difference was not significant. One year after the production area had been cleaned, the 44 employees who still worked in the factory were retested. After correction for an age/related increase in serum PCB (0.3 ppb/year of age), serum PCB levels were unchanged. The authors postulate two possible routes of PCB absorption: dermal (from the surfaces of machines and shoes) and ingestion. Because the small dining room was next to the production area and access to washing facilities on the production floor was limited, PCB ingestion was probably commonplace. The authors recommend that buildings which have been used to store or employ products containing PCB be treated before reuse or remodeling. Efforts should be made to identify materials left behind on work surfaces of older buildings before reuse or remodeling. (Christiani et al, 1986)

Study #14

operators experienced substantially greater exposure to PCBs through the dermal route than the respiratory route

Exposure to polychlorinated biphenyls (PCBs) and influence of work practices on PCB exposure among General Services Administration (GSA) switchgear personnel were assessed. Fifty personal and area air samples and 114 wipe samples of working surfaces were collected during the performance of 13 work tasks. Eight hour time weighted averages of airborne exposures for ten of the 13 work tasks were at or below the level of National Institute for Occupational Safety and Health recommended concentration of 1.0 microgram per cubic meter. Concentrations of all Aroclors were less than the Occupational Safety and Health Adminstration standards in all samples. Relatively heavy PCB contamination was found to be present on work surfaces with which switchgear operators have daily contact. Dermal exposure of two types was conclusively demonstrated. Direct contamination occurred through contact with surfaces at the job site, and indirect contamination resulted from the inadvertent spread of PCBs from the work site primarily on the switchgear operator's skin and clothing, and on tools and equipment. The authors conclude that GSA switchgear operators experience substantially greater exposure to PCBs through the dermal route than the respiratory route. The authors recommend immediate implementation of a system designed to prevent the spread of PCB contamination through the designation of work zones as clean, transitional, or contaminated areas. (Lees et al, 1983)

Study #15

dermal contact was a major route of PCB exposure for workers

The health effects of low level exposure to polychlorinated-biphenyls (PCB) were evaluated in a survey of 205 workers (52.7 percent males and 47.3 percent females) employed at a capacitor manufacturing plant, using serum PCB levels as an indicator. The levels of PCB in the serum ranged from 0 to 424 parts per billion (ppb), with a geometric average of 18.2ppb; more than 70 percent of the workers had levels below 30ppb and only 39 percent were considered to have been actually exposed to PCB occupationally. According to the outcome of linear multiple regression analysis, the most significant predictors for the levels of PCB in the serum were cumulative occupational exposure, lifetime fish consumption, length of employment, and serum cholesterol levels; of these, length of employment and occupational exposure contributed stronger and equally to the regression analysis model for log serum PCB; serum triglycerides, serum glutamic-oxaloacetic-transaminase, serum glutamic-pyruvic-transaminase, and lactate-dehydrogenase were not significant predictors of log serum PCB. The authors conclude that there was no evidence of acute exposure to PCB in the workers employed at the electrical capacitor manufacturing facility surveyed, and that the strong contribution of length of employment and occupational exposure were indicative of the contribution of dermal contact and inhalation to the levels of PCB in the serum of the workers. (Acquavella et al, 1986)

Study #16

PCBs are easily absorbed through dermal contact

Environmental occurrences of polychlorinated biphenyls (PCBs) are reviewed, and a time independent pathway analysis is provided. Environmental sources of PCB contamination include manufacturing losses, equipment leakage, and disposal sites. Representative values of PCBs in the environment are estimated to be: atmosphere, 0.05 to 5 nanograms per cubic meter (ng/m3) in rural and urban settings; lithosphere, 0.2ng/kilogram (kg); hydrosphere, fresh water, 2ng/liter; ocean, 0.2ng/liter; biosphere, plants, 9 micrograms (microg)/kg; wildlife, 90microg/kg; freshwater fish, 2000microg/kg; marine fish, 200microg/kg; and humans, 350microg/kg. PCB intake and metabolism are examined. PCBs are easily absorbed through ingestion, inhalation, and dermal contact. They cross the placenta and are transferred to milk. PCBs are efficiently absorbed by organisms and are resistant to degradation within the body, thus accumulating at higher stages in the food chain. Because they are fat soluble, they accumulate in adipose tissue. Human dietary intake has been estimated to range from 5 to 100microg/day. Effects of high exposure to PCBs are examined. A pathway analysis is presented utilizing the exposure commitment method. Using representative values of environmental concentrations and intake rates and assumptions regarding ingestion rates, retention, and excretion data, transfer factors are determined. Given current background values of PCBs in the environment, it is estimated that 0.13mg/kg PCBs are ingested from exposure to air, plants, and meat. Further PCB intake comes from freshwater fish, providing 0.16mg/kg, and marine animals, providing 0.06mg/kg, to produce a total PCB ingestion of 0.35mg/kg. Higher PCB concentrations in indoor air, drinking water, and other exposures could increase this total. The author concludes that this analysis provides a framework for analysis of the behavior of PCBs in the environment and their transfer to humans. (Bennett, 1983)

Study #17

potential for dermal exposure was significant

A study was undertaken of the mortality experience of 3588 male and female workers at the Westinghouse Electric Corporation located in Bloomington, Indiana from 1957 to 1977. There was possible exposure to polychlorinated biphenyls (PCBs). The mortality was less than had been expected; however, there was an excess in the number of deaths resulting from brain cancer and from malignant melanomas. Investigators were not able to demonstrate statistically significant relations between excess mortality and PCB exposure. A notification letter was mailed to 3189 individuals. Anecdotal information provided by some cohort members indicated that the potential for both dermal and airborne PCB exposure during capacitor manufacture was great. The authors conclude that the decision to communicate risk information to members of a cohort should be handled separately from, and after completion of review of the scientific merits of the study. The vital status of the cohort should be updated as close to the notification date as possible. (Mazzuckelli et al, 1993)

Study #18

dermal contact with contaminated soil or groundwater will be with the more highly chlorinated compounds [because the lighter-weight PCBs volatilize away]

Performing risk assessments of polychlorinated biphenyl (PCB) contaminated sites was discussed. Considerations included differences in the toxicity of various PCB mixtures, changes in the composition of specific PCB mixtures over time or due to location and medium, and the necessity of using common sense and upper bounded risk assessments (reality checks). Evaluating the toxicity of PCBs is complicated by the historical practice of testing PCBs as mixtures; very few data on the toxicity of individual PCB isomers exist. Evaluating the toxicity of a given PCB mixture by comparing it to the toxic properties of a similar commercial mixture is a common practice that can give misleading results since the composition of the mixture in the environment changes. Alterations in PCB mixtures which make it difficult to determine the most appropriate route of exposure to use in the risk assessment were discussed using PCB contaminated soil and groundwater as examples. The composition of PCB mixtures and their toxic potency in soils and groundwater will vary since the less chlorinated congeners will vaporize leaving the more heavily chlorinated isomers behind. Dermal contact with contaminated soil or groundwater will be with the more highly chlorinated compounds. Reality checks are useful for preventing a combination of seemingly reasonable assumptions from resulting in an unreasonable risk estimate. The use of reality checks was illustrated by considering the risk presented by contact with a PCB contaminated surface. (Putzrath, 1992)

Study #19

dermal exposure (especially in accidents) should be considered an important route of exposure

A review of the impact of chlorinated biphenyls (PCBs) on reproduction is presented. PCBs are able to pass the placenta; accumulation in offspring is mainly achieved by breast feeding. Disturbances of fertility and embryotoxicity were detected in animals; teratogenicity without maternal toxicity was only observed in mice. In animal experiments disturbances of fetal and postnatal development were detected as well as in human studies. Neurotoxicity was observed even at low-level exposures in monkeys, which are most comparable to humans because of the development of the same clinical symptoms. Technical PCBs which are dominating in occupational and environmental exposure until now must be judged as toxic for reproduction: dermal exposure (especially in accidents) should be considered as an important route of exposure beside inhalation. Work to list possible PCB exposure risks and to develop ways to reduce these risks are necessary now. (Popp et al, 1993)

Study #20

PCBs absorbed through the skin from contamination sites range from 1 to 10 percent

Ways to measure the degree of accidental human exposure to polychlorinated dibenzofurans and dioxins are considered. Fires, explosions, and other accidents in equipment containing polychlorinated biphenyls (PCBs) can result in possible exposure of fire fighters, cleaning personnel and other workers. Inhalation, dermal contact, and ingestion are the possible routes of exposure. Exposure can be indirectly assessed by analyses of wipes used to clean up the waste, air samples, water samples, and clothes. These assessments are indirect because the amount absorbed through the skin is 1 to 10 percent, via inhalation 50 to 70 percent, and via ingestion 50 to 90 percent. The analysis of wipes is considered to be the most important method. Comparisons are made of PCB concentrations found in wipe samples from various PCB accidents; there can be a large variation in PCB concentrations. Results of other indirect assessment methods in air and water are discussed. Direct assessments of exposure to PCBs are reviewed, including analyses of blood samples, adipose and other tissue samples, feces, and bile. PCB concentrations found in blood samples and adipose tissue from various accidental exposures are presented. Procedures for managing PCB accidents are outlined. Steps include: informing workers, industrial hygienists, and authorities; coordinating sampling and cleaning activities; analyzing PCB concentrations; contacting and using an effective cleaning firm; and resampling and waste disposal. (Rappe et al, 1985)

Study #21

NIOSH recommends workers wear gloves to protect against dermal PCB contact

This testimony concerns the proposed rule from the Environmental Protection Agency on polychlorinated biphenyls; exclusions, exemptions and use authorizations. NIOSH recommends that polychlorinated biphenyls (PCBs) be regarded as potential human carcinogens and that worker exposure to PCBs be controlled to the lowest feasible limit. Measures for controlling exposure to PCBs include good work practices, routine monitoring for PCBs, use of protective equipment, and worker training. NIOSH believes that the use of protective gloves should be required when handling materials potentially contaminated with PCBs. NIOSH also believes that in addition to Viton, other effective and less expensive glove materials such as butyl, neoprene, Saranex Tyvek, nitrile, Viton-SF, and Teflon should be permitted to help control dermal exposure to slightly contaminated fluids. Two other concerns are also noted: concern for PCB contamination of investment casting waxes, and concern for decomposition products of incomplete combustion of PCBs to polychlorinated dibenzofurans. (Lemen, 1987)

Study #22

partition coefficients obtained for PCBs partitioning into stratum corneum can be useful for evaluating risks following PCB dermal exposure

Investigations on in-vitro partitioning of 4-acetamidophenol (103902) (AAP), 4-cyanophenol (767000) (CYP), 4-iodophenol (540385) (IP), 4-pentyloxyphenol (POP), DDT (50293), or a polychlorinated biphenyl (PCB) mixture containing 54% chlorine into stratum corneum were summarized. The purpose was to assess the usefulness of partition coefficients in evaluating risks due to dermal exposure to toxic chemicals. AAP, CYP, IP, POP, DDT, or the PCB mixture was dissolved in water or isopropyl-myristate (IPM) and placed in vials to which were added samples of full thickness skin, stratum corneum, dermis, or stratum corneum plus epidermis obtained from human cadavers, Rhesus-monkeys, or hairless-guinea-pigs. The vials were incubated at 25 degrees-C for up to 48 hours. Partition coefficients were computed. IP and POP, which were lipophilic, reached equilibrium within 6 hours, as evidenced by the consistency of the partition coefficients. The partition coefficients of AAP and CYP, which were lipophobic, increased progressively with time. The partition coefficients of AAP, CYP, IP, and POP between water and the human samples decreased with increasing initial concentration. The decreases were least pronounced for the stratum corneum samples. Partitioning of AAP and POP from water into stratum corneum was greatest for monkey skin followed by guinea-pig and human skin, in that order. The partition coefficients for AAP, CYP, IP, POP, DDT, and the PCB mixture between stratum corneum and water or IPM overall were well correlated with each other and with published values for partitioning between octanol and water. The authors conclude that partition coefficients obtained for toxic chemicals partitioning into stratum corneum can be useful for evaluating risks following dermal exposure. (Surber et al, 1990)

Study #23

office workers may be exposed to PCBs, furans and dioxins via dermal contact after transformer or capacitor fires in their building

A number of fires involving polychlorinated biphenyl (PCB)-containing transformers and capacitors have occurred in the United States. PCB fires generate by-products such as polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzodioxins (PCDDs) and, when the transformer is in a building, contaminate the interior. Considerable concern exists over the potential human health effects associated with exposure by inhabitants to residual levels of PCBs, PCDFs and PCDDs. Office workers, for example, may be exposed to these chlorinated compounds via inhalation of contaminated particulates and vapors, dermal contact with contaminated surfaces, and incidental ingestion of dusts. A wide range of re-entry or cleanup levels have been developed for PCDDs and PCBs to protect workers who re-occupy a building following a PCB fire. Re-entry criteria have been used by property owners and regulatory agencies to determine whether the building is safe to re-occupy or to determine the extent of needed remediation. (Michaud et al, 1994)

Study #24

dermal absorption data from liquid-organic or aqueous-organic mixtures may underestimate the risk of exposure to TCB-contaminated soil

TCB is one of the dioxin-like polychlorinated biphenyls (PCBs). This research was designed to help assess the risk of occupational and environmental TCB exposure. To evaluate exposure variables' effects on dermal absorption and cutaneous disposition, 14C-TCB (40 microg/cm(2)) in acetone, methylene chloride, a water-acetone mixture, and a soil-based mixture were applied in an ex-vivo pig-skin-flap model (n = 4-5/treatment). Dermal absorption (0.11-0.66%, 8 hr) and penetration (1.14-2.48%) varied according to exposure conditions. Acetone and methylene chloride vehicles differed in absorption profiles and skin penetration patterns but were similar in absorption amounts. Adding water to the acetone did not change absorption but did alter the penetration pattern. The non-occluded soil-based mixture showed more absorption than did the liquid vehicles (p<0.05), but occlusion significantly (p<0.05) decreased that absorption (0.66-->0.29%, 8 hr) and penetration (2.48-->1.11%). In conclusion, dermal absorption data from liquid-organic or aqueousorganic mixtures may underestimate the risk of exposure to TCB-contaminated soil. (Qiao et al, 2000)

Study #25

dermal PCB application was used to test PCB toxicity

A fire involving a polychlorinated biphenyl (PCB)-containing transformer extensively contaminated the State Office Building in Binghamton, New York (USA), with a sootlike material containing 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), 2,3,7,8-tetrachlorodibenzofuran and high concentrations of numerous other polychlorinated dibenzodioxins, dibenzofurans and PCB. The oral LD50 of the soot and its benezene extract, each administered to female guinea pigs in 0.75% aqueous methyl cellulose, were 410 mg soot/kg and 327 mg soot equivalent/kg, respectively. Serum triglycerides were elevated in males at 100 and 500 mg/kg and in females at 500 mg/kg. Alkaline phosphatase was lowered in females at 500 mg/kg. Histopathology revealed dose-related pancreatic duct hyperplasia and salivary gland duct metaplasia in males. Body weight loss was observed in both sexes at 500 mg/kg. Thymus weight decreased in both sexes at 100 and 500 mg/kg, and kidney weights decreased in males at these doses. Dermal application of soot to rabbits for 24 h caused no overt toxicity, although hepatic centrilobular hypertrophy was observed in both sexes. Similar application of soot extract caused a local serous inflammation in addition to the hepatic centrilobular hypertrophy. The oral LD50 for 2,3,7,8-TCDD in female guinea pigs was 19 mug/kg in aqueous methyl cellulose and 2.5 mug/kg in corn oil. The soot matrix altered the dermal but not the oral toxicity of its components, the toxic effects were consistent with those reported after exposure to dibenzodioxins and dibenzofurans and the aqueous vehicle markedly diminished the acute toxicity of 2,3,7,8-TCDD relative to that in corn oil vehicle. (Silkworth et al, 1982)

Study #26

electrical workers had frequent skin contact with PCBs and other dielectric oils

Exposures to potentially confounding chemical and physical agents were estimated as part of a study on the relationship between cancer and chronic exposure to electric and magnetic fields among electrical workers. Confirmed or suspected carcinogen (CSC) exposure estimates for 64 job categories from 1950 through 1990 were presented for the Hydrouebec electrical utility. A list associating 57 tasks and general exposures with exposure to one or more CSC was provided. Interviews of foremen and senior workers identified 24 CSC and 15 surrogate exposures present at the facility. Long term exposure was limited to skin exposure to dielectric oils. Acute inhalation exposure to asbestos (1332214), carbon dust, chromium (7440473), nickel (7440020), and methylene-chloride (75092) and skin exposure to mineral oils, polychlorinated biphenyls (PCB) and sunlight were considered for equipment electricians and mechanics in generation and substation repair and maintenance. Regular dermal exposure to wood preservatives was seen for distribution linemen. Exposures for other trades were considered low or rare. No chronic exposures were found to exceed threshold limit values (TLV). Exposure data on 11 CSCs identified in the OSHA National Health Sampling Results as well as surrogate exposure were summarized. Estimated exposures to CSCs classified by job category and time weighted average inhalation exposure were provided. Exposures to specific agents such as asbestos, dielectric oils and PCBs, diesel and gasoline exhaust, herbicides, soldering and welding fumes, solvent use, paint, and wooden poles and wood treatment, were discussed. Activities involving acute exposure to asbestos included cutting/removing gaskets, installing or removing asbestos wrapping, brake work on vehicles or turbine alternators, and working with asbestos blankets, panels or tiles. Dielectric oils and PCBs were the most common exposures, with 21 trades having regular skin contact. The authors conclude that long term exposure rarely exceeded 25% of the TLV for a CSC. (Deadman et al, 1995)

Study #27

PCBs can penetrate the skin readily when applied as a solid or aqueous paste or suspension, or when dissolved in ethanol
HCB absorption was greater after solids application than after application in ethanol or as an aqueous paste or suspension.
80-90% of HCB was removed by washing
TCB absorption did not vary significantly with type of application
61-90% of TCB was removed by washing
5-8% of the doses were absorbed

The effect of physical form on the dermal absorption of 2-sec-butyl-4,6-dinitrophenol (88857) (DNBP), 2,4,5,2',4',5'-hexachlorobiphenyl (35065271) (HCB), and 3,4,3',4'-tetrachlorobiphenyl (32598133) (TCB) was studied in rats. Female Fischer-344-rats were treated topically with 0 or 2.3 micromoles (micromol) carbon-14 (C-14) labeled DNBP or HCB, or 0.5micromol C-14 labeled TCB. The compounds were applied as a solid, aqueous paste or suspension, and as an ethanol (64175) solution. Treated sites were occluded, washed with a 1:1 soap/water mixture 24 hours later, and reoccluded. The amounts of radioactivity removed in the washes were measured. Urine and feces were collected for 5 days and assayed for C-14 activity. The animals were killed 5 days postexposure to determine the amounts of radiolabel in the blood, treated and untreated skin areas, and carcass. Approximately 50% of the DNBP was absorbed through the skin over 5 days. The degree of DNBP absorption was not affected by the form in which it was applied. Washing the skin 24 hours post treatment removed 40 to 50% of the recovered dose. Urinary excretion was the primary route of DNBP elimination. Following application of HCB, 5 to 8% of the dose was absorbed. The degree of absorption was greater after application as a solid than after application in ethanol or as an aqueous paste or suspension. Approximately 80 to 90% of the recovered C-14 label was removed by skin washing. Fecal elimination was the major route of excretion. Following application of TCB, approximately 6 to 8% of the dose was absorbed. The degree of absorption did not vary significantly with the form in which the doses were applied. Sixty one to 91% of the recovered dose was removed by washing. The primary route of TCB elimination was the feces. The authors conclude that DNBP, HCB, and TCB can penetrate the skin readily when applied as a solid or aqueous paste or suspension or when dissolved in ethanol. Topical exposure to the various physical forms of each compound presents about the same level of risk of potential systemic toxicity. (Hughes et al, 1992)

Study #28

HCB had greater absorption in young rats
skin absorption of most of the compounds studied is age and dose dependent in female rats

The influence of age on percutaneous penetration of pesticides was studied in rats. Carbon-14 (C-14) labeled atrazine (1912249), captan (133062), carbaryl (63252), carbofuran (1563662), chlordecone (143500), chlorpyrifos (2921882), dinoseb (88857), disodium-methanearsonate (144218) (DSMA), folpet (133073), monosodium-methanearsonate (2163806) (MSMA), nicotine (54115), parathion (56382), 2,4,5,2',4',5'-hexachlorobiphenyl (35065271) (HCBP), or permethrin (52645531) in acetone were applied to the clipped mid dorsal skin of young (33 day old) and adult (82 day old) female Fischer-344-rats. Three doses were used, generally ranging from around 0.01 to 3.0 micromoles per square centimeter. Seventy two hours later, the animals were killed. Blisters, treated skin, urine and feces, and carcasses were analyzed to determine compound absorption and recovery of radioactivity. Fractional penetration values and C-14 recoveries of the pesticides were tabulated. The compounds showed a wide range of fractional skin penetration values in young and adult rats, the extent of penetration ranging from 1 to 90 percent. Recovery of the compounds averaged 88.8 percent and was similar for young and adult rats. No clear age related pattern of dermal absorption was seen. Atrazine, carbaryl, chlorpyrifos, and HCBP had greater absorption in young rats, whereas carbofuran, captan, dinoseb, DSMA, MSMA, nicotine, and parathion were absorbed to a greater extent in adults. Chlordecone, folpet, and permethrin did not show any significant age dependent differences in skin absorption. Median penetration values decreased in both young and adult rats with increasing dose; median penetration values were always higher in adult rats. The authors conclude that skin absorption of most of the compounds studied is age and dose dependent in female rats. (Shah et al, 1987)

Study #29

in 5 days, about 43-45% of the HCB was absorbed through rats’ skin
absorption was faster in young animals
most of the absorbed HCB remained in the body

Penetration of 2,4,5,2',4',5'-[14C]hexachlorobiphenyl (HCB) through skin of young (33 days) and adult (82 days) female Fischer 344 rats was determined in vivo and by two in vitro methods. In vivo dermal penetration at 120 hr was 45% in young and 43% in adults. At 72 hr in vivo dermal penetration was 35% in young and 26% in adults compared to 1.5% for young and 1.0% for adult as measured with a continuous flow in vitro system and 2.9% for young and 1.9% for adults as measured with a static in vitro system. Most of the dermally absorbed HCB remained in the body as only 4.9 and 2.6% of that absorbed was excreted by young and adult rats, respectively, at the end of 120 hr. Significant differences in dermal penetration and kinetics of HCB between young and adult female rats were observed. The elimination of HCB-derived material was approximately six times higher in feces than in urine. A physiological pharmacokinetic model was fitted to the organ and tissue radioactivity distribution data. Parameters in the model determined from dermal dosing of female Fischer 344 rats were in reasonable agreement with those reported in the literature for adult male Sprague-Dawley rats (iv dose). The rat constant for dermal penetration was 0.83 x 10(-4) min-1 for adults and 0.96 x 10(-4)min-1 for young. The delay or lag time parameter for dermal penetration was 4.4 hr in adults and 1.1 hr in young. (Fisher et al, 1989)

Study #30

skin contact with PCBs can pose a significant risk

The report is an assessment of human health risks associated with hypothetical PCB releases from natural gas pipelines. Using methodologies consistent with U.S. EPA guidelines for risk assessment, five hypothetical release scenarios were evaluated -- release from an active line; release from an abandoned line; release from an active line under a river; release from an abandoned line under a river; and a direct release into a flowing waterbody. Risks associated with both abandoned and active line releases were well within the typically acceptable risk range (1.0E-04 to 1.0E-06), with one exception--the direct exposure of a third party under an accidental release in which significant amount of PCBs contacts the skin. The generic nature of the risk assessment and the highly conservative nature of many assumptions builds a high degree of uncertainty into the results of these hypothetical release scenarios. The uncertainty leads to an overestimation of risk, beyond that typically applicable for site- (incomplete abstract). (Walsh et al, 1993)

Study #31

the chief concern was skin contact with PCBs

In response to a request from the State of Washington Division of Health Services, an investigation was made of possible polychlorinated-biphenyl (1336363) (PCB) contamination at the Catherine Blaine School (SIC-8211), Seattle, Washington. In October of 1984 ballast burnouts had occurred in three classrooms at the school, resulting in high concentrations of PCBs in the air and on surfaces in these rooms. PCB concentrations ranged from 0.19 to 2.4 micrograms/100 square centimeters (microg/100cm2) in surface samples taken in the three Blaine School classrooms. Concentrations ranged from 0.25 to 1.2microg/100cm2 in classrooms without reported incidents of ballast burnout. Air samples in the three classrooms showed PCB concentrations ranging from 0.8 to 1.2micrograms/cubic meter (microg/m3). In two other schools, Ingraham and Bryant, where burnout incidents had been reported, PCBs were not detected in 11 surface samples taken from rooms which had burnouts nor in eight samples where burnouts had not occurred. In a third school, Seward, where burnouts occurred, PCBs were detected in a range of less than 0.1 to 3.1microg/100cm2. In both the Blaine and Seward schools the PCB concentrations on surfaces coming into contact with the skin were generally nondetectable. The author concludes that the contamination does not present an immediate health risk to students or faculty. Recommendations are offered for the proper cleanup procedure to follow when a PCB containing ballast fails. (Kominsky, 1987a)

Study #32

a major concern was skin contact with PCBs

In response to a request from the Governor's Expert Advisory Panel concerning reoccupance guidelines for the New Mexico State Highway Department General Office Building, background levels of polychlorinated biphenyls (1336363) (PCBs), polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) were determined in three office buildings (SIC-9199) located in Santa Fe, New Mexico. Fresh air intake plenums were sampled, surfaces in high skin contact areas were tested for (PCBs), (PCDFs), and (PCDDs), and interior surfaces of plenums were tested. Levels of PCBs on surfaces ranged from nondetectable to 5.9 micrograms/square meter (microg/m2), and in the air intake plenums from nondetected to 34 microg/m2. Concentrations of PCDFs and PCDDs on surfaces ranged from 0.04 to 0.42 nanograms (ng)/m2. Concentrations in the air of the building ranged from nondetectable to 0.18 microg/m3 for PCBs and from 0.15 to 1.5 picograms (pg)/m3 for 2,3,7,8-tetrachloro-dibenzo-p-dioxin (1746016). The author concludes that these levels were all below the reoccupancy guidelines which had been established prior to this incident. (Kominsky, 1987b)

Study #33

protective equipment is recommended to avoid skin contact with PCBs

This data sheet covers: how to recognize and where to expect polychlorinated biphenyls; toxic effects; accidental causes of spread and preventive measures (preventive maintenance of transformers and capacitors containing these insulating liquids, waste disposal); rules for the installation of equipment containing PCBs (outdoors and indoors); occupational safety (responsibilities, administration, instruction of personnel, wearing of personal protective equipment to avoid skin contact and inhalation, personal hygiene); decanting of PCBs; maintenance work and sampling; measures to be taken in the event of leakage; rules for transportation and storage; treatment of waste; labelling and identification; fire prevention and fire fighting; reference to the relevant Netherlands regulations. (Netherlands, 1985)

Study #34

skin contact with PCBs is considered a risk

Numerous fire-related incidents involving electrical equipment containing polychlorinated biphenyls (PCB's) have resulted in widespread contamination of buildings with PCB's and, in some cases, with polychlorinated dibenzofurans (PCDF's) and polychlorinated dibenzo-p-dioxin (PCDD's), including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Emergency response personnel, maintenance or cleanup workers, or building occupants may be exposed to the compounds by inhalation, ingestion, or skin contact. Based on existing evidence, the National Institute for Occupational Safety and Health (NIOSH) continues to recommend the PCB's and TCDD be regarded as potential human carcinogens in the workplace. Existing evidence also suggests that PCDF's may pose a risk to human health. Therefore, NIOSH recommends that occupational exposure to PCB's, PCDF's, and PCDD's resulting from electrical equipment fires or failures be controlled to the lowest feasible limit, and that workers involved in decontamination activities (incomplete abstract) (NIOSH, 1986)

Study #35

workers should avoid skin contact with PCB containing materials

The detection, isolation and collection, treatment, disposal, and handling of polychlorinated biphenyls (PCBs) is discussed. PCBs can be found in industrial capacitors and transformers, heat transfer fluids, and hydraulic and binding oils. The accepted identification technique for low level concentrations involves use of an electron capture gas chromatograph. Closed systems containing PCBs can be purged by substituting other compounds. Low levels of PCBs can be removed from waste streams by carbon adsorption and regeneration, destruction by dechlorination using ultraviolet assisted ozone, and adsorption on resins and other materials. Workers should avoid skin contact with PCB containing materials. (Russell, 1977)

Study #36

researchers found a low dermal absorption rate in one volunteer subject

In a controlled experiment simulating the accidental contact with PCB and thus the dermal absorption a uniformly labeled 13C-PCB mixture was applied to the skin of a volunteer. Blood samples were collected after the application and the concentrations of 13C-PCBs determined using GC. The results show that under the selected conditions of application percutaneous absorption of PCBs is at maximum 6% of the absorption after oral intake of the same amount. Following the accidental release of PCBs from a capacitor in a mechanical workshop in Switzerland plasma levels were determined in workers charged with cleaning, who had contact with the capacitor fluid. These data confirm the conclusion of a low dermal absorption rate derived from the experimental study and support the view that accidental dermal contact with PCB does not represent a major health hazard. (Schmid et al, 1992)

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