Mobility and Dissipation of 14C-Labeled Atrazine, Metolachlor, and Primisulfuron in Undisturbed Field Lysimeters of a Coastal Plain Soil

Abstract

Mobility and dissipation of 14 C-labeled atrazine, metolachlor, and primisulfuron were evaluated for 1 year when applied preemergence to fallow loamy sand soil column field lysimeters. The relative mobility of the herbicides and/or metabolites in field lysimeters over the 1 year period in descending order was metolachlor>atrazine=primisulfuron. Thirty days after treatment, losses of 14 C due to apparent volatilization, with other loss mechanisms being involved, accounted for 57, 43, and 62% of the applied 14 for atrazine, metolachlor, and primisulfuron, respectively. Chemical analysis of the 0-8 cm layer showed the presence of four metabolites for atrazine, two for metolachlor, and two for primisulfuron. Calculated half-lives were 4 days for atrazine, 7 days for metolachlor, and 5 days for primisulfuron