A. Manninen et al., DETERMINATION OF URINARY 2-MERCAPTOBENZOTHIAZOLE (2-MBT), THE MAIN METABOLITE OF 2-(THIOCYANOMETHYLTHIO)BENZOTHIAZOLE (TCMTB) IN HUMANS ANDRATS, Archives of toxicology, 70(9), 1996, pp. 579-584
A method for biological monitoring of urinary 2-(thiocyanomethylthio)b
enzothiazole (TCMTB), a wood preservative and an industrial chemical,
was developed. Three different doses of TCMTB in olive oil were given
to male rats by gavage for 3 weeks. Urine was collected daily and the
metabolites were analysed as thioethers by derivatization with pentafl
uorobenzyl-bromide by gas chromatography-mass spectrometry. The parent
chemical was not detected in urine samples, but two metabolites of TC
MTB were identified. 2-Mercaptobenzothiazole (2-MBT) was the main meta
bolite, and its excretion varied according to the dose. The second met
abolite was 2-(mercaptomethylthio)benzothiazole. The amount of 2-MBT e
xcreted in rat urine was 66 +/- 12% (SD), 51 +/- 20% and 44 +/- 9% for
TCMTB doses of 15, 75 and 150 mg/kg, respectively. Two doses, 75 and
150 mg/kg, caused diuresis in rats during the 1 week of dosing. During
the 3-week TCMTB treatment, rat liver microsomal CYP enzyme profile w
as not significantly changed. Urine samples of sawmill workers exposed
to TCMTB were collected after their work shifts for exposure assessme
nt. TCMTB could not be detected in the urine samples of exposed worker
s. Most concentrations of 2-MBT were below the limit of the detection,
0.12 mu mol/l, the concentrations were 0.12-0.15 mu mol/l only in few
cases. The determination of 2-MBT in urine, when a sample is taken im
mediately after a work shift, is a suitable indicator of workers' expo
sure to TCMTB.