Distribution of radioactivity and identified compounds in the four soils are shown in Tables 8.1.1-15 to 8.1.1-18, respectively. Total recoveries ranged from 92.9% to 103.3%. Non-extractable radioactivity increased throughout the study to give maximum levels on day 233 for three of the four soils where they ranged from 35.1% to 46.7%. The fourth soil (Otzberg) gave a maximum level of 46.6% of non-extractable radioactivity on day 120, but was still at 42.3% on day 233. Volatile radioactivity identified as 14CO2 represented 10.0% to 32.4% of the applied radioactivity by day 233. Metabolites identified as >10% of the applied radioactivity were Desmethyl sulfosulfuron, Sulfonamide, and Guanidine. Desmethyl sulfosulfuron reached max 33.5% AR in Itingen soil (I). Max levels in the other soils ranged from 6.4-20.5%. Sulfonamide reached max 23.2% in Speyer 2.2 soil (II). In the other soils it reached 6.3-8.4%. Levels of both these metabolites decreased towards the end of the incubation period. Guanidine reached max 18.8% in the Otzberg soil (III). In the other soils Guanidine reached max 4.9-14.6%. Levels of Guanidine decreased towards the end of the study in two of the soils, in the other two it was still increasing or had reached a plateau at study end. The only other identified metabolite of note was Aminopyrimidine, which reached a maximum level of 9.6% on day 14 in the Speyer 2.2 soil (II) and remained above 5% until day 154 by which time it had decreased to 4.4%. In the other soils Aminopyrimidine was present as <5% AR except on two sampling dates (days 7 and 28) in the Wormingford soil (IV). Two other low-level metabolites were identified, Urea and Sulfonylbiuret, which reached maximum levels of 2.3% and 5.2% of the applied radioactivity, respectively. Five unidentified metabolites were detected at low levels in at least one soil: M5, M8, M9, M10, and M11. Each metabolite accounted for a maximum of 0.8 to 3.8 % of applied radioactivity. The pathways were based on the results from the present [soil lysimeter] study, as well as the results of aerobic soil degradation studies. Direct hydrolysis of the urea bridge of Sulfosulfuron leads to Sulfonamide and Aminopyrimidine (not shown in figure). This transformation would occur via an intermediate of an unstable carbamic acid. Oxidative demethylation gives Desmethyl sulfosulfuron. Demethylation renders the pyrimidine moiety of Sulfosulfuron susceptible to hydrolysis which results in the ring opened Guanidine and Sulfonylbiuret. Hydrolysis of the terminal urea moiety of the biuret metabolite leads to Sulfonylurea. Hydrolysis of the sulfonylurea linkage of the Sulfonylurea, Guanidine or Sulfonylbiuret metabolites also results in formation of Sulfonamide.