In soil, thiabendazole is degraded into the principal metabolite benzimidazole (maximum occurrence 2.2%), with small amounts of 5-hydroxythiabendazole (maximum occurrence <0.5%). The only residue present at 10%, or more, of the initially applied radiocarbon is the parent thiabendazole. In conclusion, only minor metabolites of thiabendazole are observed under aerobic and anaerobic conditions. The formation and degradation of non-extractable (bound) residues and mineralization to carbon dioxide represent the main overall pathways for the metabolism of thiabendazole.