Percutaneous absorption of m-xylene vapour in volunteers during pre-steady and steady state

Percutaneous absorption of m-xylene (XYL) was determined in volunteers exposed to 29.4 μg cm-3 XYL vapour on the forearm and hand for 20, 45, 120 and 180 min. The internal exposure was assessed by measuring the concentration of XYL in exhaled air. The systemic kinetics were determined using a reference exposure by inhalation. The dermal permeation rate and the cumulative absorption of XYL as a function of time were calculated using mathematical deconvolution. From these relationships, the average flux into the skin throughout the exposure (Jskin, average) and the maximal flux into the blood (Jblood, max) were derived. Both fluxes were dependent on the duration of exposure, approaching each other at longer exposure durations. The values of Jskin, average, adjusted to a concentration of 1 μg cm-3, were 0.091 μg cm-2 h-1 during 20-min exposure falling to 0.072, 0.066 and 0.061 μg cm-2 h-1 for 45, 120 and 180 min, respectively. The values of Jblood, max showed an opposite trend, gradually increasing from 0.034 μg cm-2 h-1 at an exposure duration of 20 min to 0.042, 0.059 and 0.063 μg cm-2 h-1 for 45, 120 and 180 min of exposure durations, respectively. [Copyright &y& Elsevier]