Determination of imidazolidine-2-thione (ethylenethiourea) in ethylenebisdithiocarbamate formulations

Zineb was most seriously contaminated with imidazolidine-2-thione (ethylenethiourea; ETU), followed by mancozeb, and maneb. The type of formulation also affects ETU generation and a wettable powder produced ETU more easily than a flowable formulation. The ETU contents of the ethylene-bisdithiocarbamate (EBDC) mixed fungicides formulations were erratic. Low ETU contents were found in EBDC mixed fungicides, even though some samples had been stored in the laboratory for five years. The cupric ion and the N. O- containing group of other fungicides might have a stabilizing effect on the degradation of EBDC to ETU. The survey indicated that EBDC mixed formulations could be a useful means of suppressing ETU generation in commercial products.