Lenacil degradation in the environment and its metabolism in the sugar beets.

14C-Lenacil photolysis and hydrolysis studies were conducted at 2 ppm in sterilized buffers at pH 5, 7, and 9 for up to 15 and 30 days, respectively. The degradation of (14)C-lenacil in three soils and in two sediments systems was monitored for up to 100 days. Residue level and metabolites were analyzed in sugar beets following the application of (14)C-lenacil at 4- and at 6-leaf stages at the rate of 204 g ai/ha and 321 g ai/ha, respectively. Lenacil was stable in the dark and at pH 5 and 7 under irradiation. At pH 9 under irradiation, the half-life (DT(50)) was 41 days. Lenacil DT(50) in three soils ranged from 81 to 150 days. The DT(50) in two sediments ranged from 32 to 105 days. In mature sugar beets, the total radioactive residue was 0.16 ppm in the tops and <0.03 ppm in the roots. The majority of lenacil metabolites identified were hydroxylated or oxidized products and their conjugates.