The Effects of Salts and Grease on BTEXs Gas/Sweat Equilibrium Partition: The Effects on Human BTEX Dermal Exposures

ABSTRACT

Human dermal exposure to volatile organic compounds (VOCs) occurs via absorption through sweat on the skin surface. Those working under hot conditions with VOCs are most susceptible. To assess dermal exposure risk to gaseous VOCs, equilibrium partitioning coefficients (p_c) at the air–sweat interface must be analyzed. This study determined the p_c values of benzene, toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene (BTEXs) in liquid concentrations of around 0.5–5 mg/l at the air–water and air–sweat interfaces at 27–47°C. The salt contents (sodium chloride, urea, ammonia, and sodium lactate) in the artificial sweat increased the p_c values of BTEXs. However, the mixture of grease (triolein and Tween 85) and salts decreased the p_c values of BTEXs. The values of p_c at 27–37°C decreased to about 21.68–60.53% for BTEXs in artificial sweat than those in pure water. The co-effect of salt and grease on p_c was elucidated further using the n-octanol-water partitioning constants (K_ow) of BTEXs. According to analytical results, the p_c of BTEXs at the air–water interfaces were larger than those for air–sweat, and the p_c data were utilized to assess risk for human dermal exposure to BTEXs.

Key Words:

• sweat
• skin
• volatile organic compound
• partition
• exposure

ACKNOWLEDGMENT

The authors thank the National Science Council, Taiwan, Republic of China, for financially supporting this research under contract Nos. NSC 94-2211-E-242-002 and NSC 95-2815-C-242-001-E.