Polychlorinated biphenyls (PCBs): dermal absorption, systemic elimination, and dermal wash efficiency

Area of Science:

• Toxicology
• Environmental Health
• Dermatology

Background:

• Polychlorinated biphenyls (PCBs) are persistent organic pollutants with known health risks.
• Understanding the dermal absorption and elimination of PCBs is crucial for assessing human exposure risks.

Purpose of the Study:

• To quantify the dermal absorption of PCBs in animal models.
• To evaluate the efficiency of dermal washing in removing PCB contamination.
• To determine the systemic elimination kinetics of PCBs following dermal and parenteral exposure.

Main Methods:

• 14C-labeled PCBs (42% and 54% chlorine) were administered topically and parenterally to guinea pigs and rhesus monkeys.
• Dermal absorption was assessed by measuring 14C urinary excretion.
• Dermal wash efficiency was determined by washing skin with water and acetone at different time points.
• Systemic elimination was monitored by quantifying 14C excretion in urine and feces over time.

Main Results:

• Extensive dermal absorption of PCBs was observed in both species.
• In guinea pigs, 33-56% of applied PCB doses were absorbed.
• In rhesus monkeys, 15-34% of applied PCB doses were absorbed.
• Dermal washing, even immediately after application, removed only 59% of the dose.
• Post-contamination washing showed limited effectiveness in removing PCBs from the skin.
• Slow systemic elimination was observed, with elimination half-lives of 2-7 days.
• Topical administration resulted in elimination half-lives not significantly different from parenteral administration, suggesting rapid skin penetration.

Conclusions:

• PCBs are rapidly and extensively absorbed through the skin.
• Dermal washing is insufficient to completely remove PCB contamination.
• PCBs are distributed systemically after dermal exposure and eliminated slowly from the body.