Reducing Systemic Absorption from Monochloracetic Acid Exposure Through Dermal Decontamination: Use of the Pig Ear Organ Culture System

Abstract

Severe systemic intoxication may occur after skin contamination with monochloracetic acid (MCA). For this reason the effects of decontaminating with either water (most commonly used) or bicarbonate on the rates of percutaneous penetration and dermal accumulation of radiolabeled MCA were measured using the blood-perfused pig ear model. The rate of percutaneous penetration of a 40% solution of MCA was measured after exposure times of 1, 3, and 10 min. Maximal rates of percutaneous penetration (ng/min/cm²; mean ± SEM) were 891 ± 335 for a 1 min exposure; 947 ± 191 for a 3 min exposure; and 3221 ± 515 for a 10 min exposure. Although the initial rate of percutaneous absorption (first 30 min) was directly related to the exposure time, there was no difference in maximal rates of percutaneous penetration for 1 and 3 min exposures. It appears, that for short exposure times, the percutaneous penetration rate is determined by both the rate of penetration into the skin and the rate of diffusion from dermal stores into the blood.

A saturated sodium bicarbonate solution and water proved equally effective in decontaminating the skin after a 10 min exposure to MCA. However, a saturated bicarbonate solution was a slightly more effective decontaminant than water after a 1 min exposure. Our data indicate that decontamination should take place as soon as possible after dermal contamination with MCA. Furthermore, decontamination should continue for as long as possible in order to reduce the systemic burden. In view of the toxicity of MCA and the speed with which dermal deposits can accumulate, it is essential that decontamination facilities (e.g., a shower or bath filled with decontaminant) are available at all points in the workplace where MCA is handled.