N-ACETYL-S-(DICHLOROPHENYL)CYSTEINES AS SUITABLE BIOMARKERS FOR THE MONITORING OF OCCUPATIONAL EXPOSURE TO 1,2-DICHLOROBENZENE

A method has been developed for the simultaneous analysis of the isome ric N-acetyl-S-(dichlorophenyl) cysteines (also known as dichloropheny lmercapturic acids, DCPMAs) in urine. This procedure allows the determ ination of 2,3- and 3,4-DCPMAs at the concentrations expected in the u rine samples of employees occupationally exposed to 1,2-dichlorobenzen e (1,2-DCB). The results of a 1,2-DCB exposure study under standardize d conditions show a first-order kinetic for the excretion of DCPMAs, a s well as acceptable linear correlations between the urinary concentra tions of DCPMAs and the amount of inhaled 1,2-DCB. It therefore seems it would be possible to derive a biological tolerance value for 1,2-DC B based on isomeric DCPMAs as analytical parameters.