The use and the no. of sulfonylurea herbicides have increased since the early 1980s. A good understanding of their degrdn. is of ecol. importance, since environmental pollutants can be issued from them. It is claimed that microbial degrdn. and chem. hydrolysis present the main degrdn. pathways but photodegrdn. cannot be neglected. Time-dependent d. functional theory has been used to help in the elucidation of the photochem. behavior of sulfonylureas. [on SciFinder (R)]