[Biochemical and photochemical degradation of the herbicide lontrel].

Degradation of Lontrel by activated sludge (AS) of purification works and UV irradiation was studied. 3,6-Dichloropicolinic acid (3,6-DCPA, the main active principle of Lontrel) was not degraded by the microbial association of the AS. AS treated with nitrosourea under various conditions did not oxidize Lontrel either.