Degradation of the herbicides bromacil, diuron and chlortoluron in soil

In laboratory studies, the rate of degradation of 14C-labeled diuron, chlortoluron, and bromacil in soil was determined by monitoring 14CO 2 evolution at 25, 30, and 35°C. Degradation of the three herbicides was slow and followed the first-order rate law. The rate of 14CO 2 evolution from the treated soil was nearly tripled by a 10°C rise in temperature from 25 to 35°C. The half-lives as well as the activation energies of degradation for the three chemicals were determined and discussed.