Percutaneous absorption and skin decontamination of PCBS: In vitro studies with human skin and in vivo studies in the rhesus monkey

Abstract

Knowledge of the entry of polychlorinated biphenyls through the skin into the body and subsequent disposition aids estimation of potential for human health hazard. [14C]Aroclor 1242 and [14C]Aroclor 1254 were separately administered intravenously and topically to rhesus monkeys. Following iv administration, 30-d excretion was 39.4 +/- 5.9% urine and 16.1 +/- 0.8% feces (total 55.5 +/- 5.1%) for Aroclor 1242, and 7.0 +/- 2.2% urine and 19.7 +/- 5.8% feces (total 26.7 +/- 7.5%) for Aroclor 1254. Mineral oil and trichlorobenzene are common PCB cosolvents in transformers. Skin absorption of Aroclor 1242 was 20.4 +/- 8.5% formulated in mineral oil and 18.0 +/- 3.8% in trichlorobenzene (p greater than .05). Absorption of Aroclor 1254 was 20.8 +/- 8.3% in mineral oil and 14.6 +/- 3.6% in trichlorobenzene (p greater than .05). PCBs are thus absorbed through skin, and excretion from the body is slow. Vehicle (trichlorobenzene or mineral oil) did not affect percutaneous absorption. In vitro skin absorption in human cadaver skin did not correlate with in vivo findings. This was due to lack of PCB partition from skin into the water receptor fluid, even with addition of 6% Oleth 20 (Volpo 20) solubilizer. Skin decontamination of PCBs showed soap and water to be as effective as or better than the solvent ethanol, mineral oil, and trichlorobenzene in removing PCBs from skin. There is a dynamic time lapse for PCBs between initial skin contact and skin absorption (irreversible removal). Thus initially most PCBs could be removed from skin, but this ability decreased with time to the point where at 24 h only about 25% of the initial PCB skin dose could be recovered with skin washing.

Acephate exposure and decontamination on tobacco harvesters' hands

“…When rhesus monkeys were washed with various solvents, including soap and water, between 70 and 100% of Aroclor 1242 PCB was removed immediately following a 15 min skin application interval. The amount removed declined steadily with time, to where only 25-45% was being removed at 24 h postapplication (Wester et al, 1990). In an investigation of a hand-sampling method, where a hand is placed in a bag containing solvent and shaken, Fenske and Lu (1994) found that the removal efficiency of chlorpyrifos decreased from 43% immediately after exposure to 23% 1 h postexposure when a 10% isopropanol/distilled water solution was used as the solvent.…”

Polychlorinated Biphenyls and Polybrominated Biphenyls

“…Skin samples collected from human cadavers and exposed in vitro to [ 14 C]-labelled Aroclor 1254 and Aroclor 1242 retained 43-44% of the administered dose over a 24-hour period when the mixtures were formulated in water (Wester et al, 1990(Wester et al, , 1993. A lower retention was observed when PCBs were formulated in mineral oil or adsorbed on contaminated soil.…”

“…In rhesus monkeys, percutaneous absorption in vivo of [ 14 C]-labelled Aroclor 1242 and Aroclor 1254 formulated in mineral oil was 20.4 ± 8.5% and 20.8 ± 8.3% of the administered dose, respectively, as determined by urinary and faecal excretion of radiolabel for 30 days after topical application (Wester et al, 1990).…”

Howard I. Maibach: Extraordinary Leadership in Integrating Key Concepts Underpinning Our Understanding of Percutaneous Absorption and Occupational Dermatology

“…floors and walls) and the transfer of hazardous chemicals to human skin have been subject of major concerns to Howard and his research team, who, through numerous studies, have made important contributions in exploring human risk factors. Percutaneous absorption rates of pesticides, herbicides, and metals, such as chlordane [9], polychlorinated biphenyls (PCB) [10,11], 2,4-dichlorophenoxyacetic acid [12], arsenic [13], or cadmium [14] from contaminated soil and water were examined and compared using in vitro and in vivo methods, which included both animal and human models (table 1). From these results, Howard and his research team observed that skin acts as a lipid sink (stratum corneum) for the lipid-soluble contaminants while also serving as a transfer membrane for water and any contaminants dissolved within it.…”

“…Decontamination, involving immediate removal of the contaminant from the skin performed in the most efficient manner, is the primary intervention needed following dermal exposures. For contaminants such as PCB [16] and glyphosate [10], the decontamination system most readily available on a practical basis is washing with water and soap. Timely use of flushing with copious amounts of water may physically remove the contaminant.…”