Movement and degradation of mancozeb fungicide and its metabolites, ethylenethiourea and ethyleneurea in silty clay loam soil

Abstract
The persistence and movement of mancozeb and its metabolites, ethylenethiourea and ethyleneurea, in silty clay loam soil under Philippine field conditions were investigated using soil columns and radiotracer techniques. The degradation of mancozeb, ethylenethiourea (ETU) and ethyleneurea (EU) in soil showed a half‐life of 2.9, 2.5 and 4.8 days, respectively. Mancozeb remained in the first 2.5 cm of the topsoil fraction for 12 days only. The maximum depth of permeability for ETU was 8 cm up to 14 days after application, which was the same for EU up to 21 days. ETU degraded rapidly, with a 78% reduction at 3 days after application. It is concluded that the recommended agricultural practices for mancozeb application, under lowland conditions, should not lead to groundwater contamination by ETU.