Major degradation pathway of thiuram in tap water processed by oxidation with sodium hypochlorite

Thiuram (3 microM), a fungicide, was incubated in deionized water by adding 0-100 mg/L free chlorine at 30 degrees C for 30 min, and the solution was analyzed by HPLC and IC. The byproducts were identified by LC/MS, EI-MS, infrared, and (13)C NMR spectra and a reduction technique using 2-mercaptoethanol. On the basis of these results, it was found that the oxidation of thiuram with sodium hypochlorite initially produced an intermediate dimethylthiocarbamoyl dimethylcarbamoyl disulfide, which was finally degraded to bis(dimethylcarbamoyl) disulfide, its trisulfide, and dimethylamine. Subsequently, it was suggested that monitoring of bis(dimethylcarbamoyl) disulfide, its trisulfide, and dimethylamine should be included for the management and control of thiuram in tap water processed by oxidation with sodium hypochlorite.