NATURAL ATTENUATION CAPABILITY OF AN AGRICULTURAL SOIL TO DEGRADE TERBUTHYLAZINE

The capability of the bacterial community of an agricultural soil to degrade the herbicide terbuthylazine has been assessed. Soil samples, collected from an area in which terbuthylazine is being applied, were used for enrichment cultures with terbuthylazine at a concentration of 2 mg L-1 as the sole carbon source. The degradation capability of the bacterial pool was evaluated in terms of herbicide disappearance and metabolite desethyl-terbuthylazine formation, by using LC-ES/MS. Moreover, the bacterial growth on the herbicide was assessed by DAPI counts and a measuring of viability. Controls with terbuthylazine in a sterile liquid mineral medium were also set up. The microbial pool proved able to degrade the herbicide without any lag phase and the terbuthylazine was halved in just 23 days with the metabolite desethyl-terbuthylazine being detected. Subsequently, isolation experiments were performed and two bacterial strains were isolated.