Development and evaluation of an HPLC urinalysis screening test for occupational exposure to 3,4- and 3,5-dichloroanilines

Abstract

Objective: In order to develop a screening test to detect human occupational exposure to aromatic amines such as 3,4-dichloroaniline (3,4-DCA) and 3,5-dichloroaniline (3,5-DCA), we first investigated the urinary excretion of these highly toxic compounds in the rat. The study was performed after both oral and dermal application, even though contact with the skin is the major route of contamination in the workplace. The aim of this study was to develop a rapid screening test for risk assessment in the workplace.

Methods: An initial group of 3 rats was treated with 40 microl of 3,4-DCA solution (30% in methanol), applied topically to the shaved dorsal skin. A second group of 3 rats were administered the same dose of the amine orally by gavage before urine sampling. The same procedure was performed with 3,5-DCA (2 other groups of 3 rats). The urine samples were collected for a period of 24 hours after treatment and the excretion of 3,4-DCA, 3,5-DCA was studied using a GC-MS and an HPLC method after urine extraction. The urine of 2 workers potentially exposed to the amines for a period of 161 and 147 days, respectively, was analyzed by the same methods with urine collection before and at the end of the work shift.

Results: The study of excretion in the rat showed that unchanged dichloroanilines and some metabolites were excreted 24 hours after administration of the amines. Based on these results, we propose an HPLC method for the screening of risk assessment in the workplace. The presence of 3,4-DCA and 3,5-DCA in the urine of workers showed that they were absorbing amines during the workshift.

Conclusions: These results successfully allowed us to detect contamination due to 3,4-DCA and 3,5-DCA in exposed workers. The HPLC method described provides a satisfactory and sensitive procedure for urine screening in the assessment and monitoring of the occupational exposure to dichloroanilines.