The Metabolism of Atrazine, Chloramben, and Dicamba in Earthworms (Lumbricus terrestris) from Treated and Untreated Plots

Abstract

The metabolism of three 14C-ring-labeled herbicides, atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], chloramben (3-amino-2,5-dichlorobenzoic acid), and dicamba (3,6-dichloro-o-anisic acid) was studied in the earthworm, Lumbricus terrestris L., taken from plots treated with these herbicides for the past 10 yr and from control plots treated with no herbicides. For the two benzoic acid herbicides, acetone extracts of sand and earthworms from untreated plots contained more unmetabolized herbicide than similar extracts of sand and earthworms from treated plots, indicating a net enhancement of metabolism in worms from treated plots. For atrazine, the amount of unchanged herbicide in the acetone extracts of earthworm and sand were nearly equivalent. Finally, the relative metabolic stability of the three herbicides in decreasing order in earthworms from both control and untreated plots was chloramben>atrazine>dicamba.