The route of degradation of sintofen was studied under aerobic, anaerobic and photolytic conditions. Under aerobic conditions, in all of the 10 soils that were studied, levels of metabolites formation were low (up to 5 unidentified components individually not exceeding 6.9% of applied radioactivity). Following the degradation pattern of sintofen, two metabolites M1 and M2 might have been minor non transient. However, because of their low or non-occurrence in 5 of the 10 soils that were tested, and considering the inteded use for CROISOR 100 (SL), they can be excluded from the risk assessment. The degradation pathway was identical in anaerobic conditions, and no new metabolites were formed. Photolysis is not expected to play a major role in the dissipation of sintofen applied as CROISOR 100 (SL). The mineralisation of sintofen was low in all the soils with 14CO2 in the range of 0.2 - 3.9% AR after 100 days. Unextraced residues reached levels in the range 9.6 - 34.3% AR after 100 days for 8 acceptable soils and measured by combustion of the soil after exhaustive extraction. In the study of Mamouni (2004a) a significant greater amount of unextractable radioactivity was present in the soils with the higher amount of organic carbon. Statistical analysis indicated an inverse relationship between the total amount of extractable radioactivity and the cation exchange capacity, nitrogen and clay content of the soils.