Parent bitertanol is relatively rapidly degraded in soil under aerobic conditions in laboratory experiments carried out at ca. 20 C and 40-50% maximum water holding capacity or 75% of field capacity (defined as 1/3 bar). In an experiment on one soil both diastereomers of bitertanol were demonstrated to decline at the same rate. Experiments with biphenyl-(1 soil) and phenyl-labelling (4 soils) demonstrate a partial oxidation of the biphenyl group leading to the minor ( 0.3 %AR) metabolite bitertanol-benzoic acid, M01 as a transient intermediate and finally to carbon dioxide by complete mineralisation of the labelled moiety of the molecule (mineralisation was 43%AR at 91 days in the biphenyl labelled experiment and 48-59%AR at 100 days in phenyl labelled experiments). Unextracted residues were 46%AR at 91 days in the biphenyl labelled experiment and 25-43%AR at 100 days in phenyl labelled experiments. An experiment with triazole-labelling (1 soil) showed that 1,2,4-triazole is formed as the major soil metabolite. In this study it was found that up to 44% AR could be accounted for as 1,2,4-triazole (at 62 days declining to 36% at study end 120 days). 53%AR was unextractable residues following extensive extraction (120 day value). In this study dosed with bitertanol mineralisation of the 1,2,4-triazole moiety was minimal (2.8% AR at 120 days). Apart from 1,2,4-triazole, no other major metabolite was observed. In studies carried out with 1,2,4-triazole as the test substance higher mineralisation rates were observed in five soils (15-52% AR at 90- 120 days) in a sixth soil mineralisation was lower (1.6%AR at 120 days). Bitertanol was shown to be stable to photolysis at the soil surface. Because 1,2,4-triazole was identified as a major metabolite, its fate and behaviour in soil was investigated separately and first order DT50 of 6.3-12.3 days at 20 C were derived. From studies with 1,2,4-triazole (aerobic and anae and triazole acetic acid (aerobic), it was concluded that 1,2,4-triazole can undergo conjugation reaction in soil leading to triazole alanine, which is subsequently metabolised into triazole acetic acid. This product can lead to 1,2,4-triazole, so a circular reaction pathway is possible. This conjugation / oxidation reaction occur rapidly in soil. It was not rate-limiting with regard to the rapid dissipation of 1,2 triazole from aerobic soil, so from the environmental fate perspective it is not a controlling pathway. Under anaerobic conditions it is possible that the circular pathway leads to the formation of final products other than carbon dioxide, which is not a terminal product in the absence of free oxygen. However when aerobic conditions return, data demonstrate that triazole acetic acid (when applied as the test substance) was then mineralised slowly (2-6%AR at 70 days), however transform to other breakdown products / formation of unextracted residues was relatively rapid (DT50 6-11).