The soil contains a large variety of macroscopic and microscopic organisms, which compete for the available resources. Fertilizers and pesticides usually applied in soil to increase the agricultural production may determine environmental changes. Among the edaphic organisms, earthworms are outstanding for their number and role they play on soil characteristics. The performance of earthworms on the persistence, transformation and bioaccumulation of simazine was assessed in a soil treated with the herbicide. The earthworms were sensitive to simazine [CL50(14 days) of 54 mg IA kg-1 soil], accumulated the compound or its metabolites in their tissues (FB = 1,03), and reduced the formation of soil bound residues (about 26 and 33%, with and without earthworms, respectively).
herbicide; persistence; sensibility; bioaccumulation