The route of degradation of bixafen was investigated in four soils with two appropriate radiolabelling positions (pyrazole and dichlorophenyl positions) in a standard aerobic degradation study. The study was performed under non-sterile laboratory conditions at 20 ̊C and 55% MWHC for 120 days. The 4 German soil types tested, (2 silt loams, a sandy loam and a loam soil) represented a range of pH of 5.4-6.4 (in 0.01 M CaCl2) and organic carbon content of 1.1-2.62 %. Although the RMS notes that only a narrow range of pH was represented by the soils tested in the laboratory degradation study (see Table B.8.2), given the physical- chemical properties of the compound and that hydrolysis is not expected to be a major route of degradation, an effect of pH on degradation is considered unlikely. The results of this study have been relied on only for triggering the requirement for field dissipation trials, (which included soils of pH 6.1-7.5), so this is not considered to impact on the risk assessment. Under aerobic laboratory conditions, bixafen showed only very slow degradation with 86.4-91.6% AR remaining as unchanged bixafen at the end of the study, (<10%AR degraded from day 0 concentration). Consequently, no major metabolites were detected above 10%AR and degradation products were formed at less than 5% AR over the study duration. With the pyrazole-radiolabel only, a minor metabolite, BYF 00587-desmethyl- pyrazole-4-carboxylic acid, was identified at levels up to 2.9% AR (silt loam), but was present at ≤0.6% AR in the other 3 soils. Other unidentified radioactivity accounted for 0.2- 2.5% AR. Mineralisation to CO2 was low at a maximum of 0.7-1.6% AR (pyrazole-label) and 0.1-0.4%AR (dichlorophenyl-label) at 120 days. Unextracted residues at 120 days ranged between 7.5-10.4% AR (pyrazole-label) and 9–12% AR (dichlorophenyl-label). There was no significant difference between the results from the two different radiolabelling positions, except for the detection of minor amounts of BYF 00587- desmethyl-pyrazole-4-carboxylic acid from the pyrazole-labelled test substance.