Dermal absorption of dihalomethane vapors

Area of Science:

• Toxicology
• Dermal Absorption Studies
• Environmental Health

Background:

• Dermal exposure is a significant route for chemical uptake.
• Quantifying dermal absorption of volatile organic compounds is crucial for risk assessment.
• Dibromomethane (DBM) and bromochloromethane (BCM) are industrial chemicals with potential for human exposure.

Purpose of the Study:

• To investigate and quantify the dermal absorption of dibromomethane (DBM) and bromochloromethane (BCM) vapors in rats.
• To establish a methodology for assessing dermal penetration of volatile dihalomethanes.
• To determine dermal flux and permeability constants for DBM and BCM.

Main Methods:

• Rats were exposed to DBM and BCM vapors in a specialized chamber with respiratory protection.
• Blood samples were collected and analyzed for parent dihalomethanes using gas chromatography.
• Dermal absorption was estimated by calculating amounts in blood, tissues, exhaled air, and metabolized bromide.

Main Results:

• Dermal flux for DBM ranged from 0.004 to 0.078 mg/cm2/hr and for BCM from 0.011 to 0.164 mg/cm2/hr.
• Permeability constants were approximately 1.12 cm/hr for DBM and 0.79 cm/hr for BCM.
• Calculated permeability constants were largely independent of exposure concentration.

Conclusions:

• Whole-body dermal vapor exposure in rodents is feasible for toxicological studies.
• The methodology allows for the quantitation of dermal penetration based on blood concentrations and metabolism.
• This study provides valuable data on the dermal absorption of DBM and BCM, informing risk assessments.