INFLUENCE OF SOME CATIONS ON THE INTESTINAL-ABSORPTION OF MANEB

Orally administered fungicide maneb [polymeric manganese ethylenebis(dithiocarbamate)] is rapidly degraded in the intestine of rats, excretion being almost complete within 3 days. After administration of [14C]maneb to female rats, about 50, 40 and 1% of 14C activity was excreted in urine, feces and exhaled air, respectively. Studies with [54Mn]maneb showed that no absorption of Mn complexes occurred. Simultaneous administration of Fe(III), Zn(II), Hg(II) and Cu(II) salts significantly reduced the excreted 14C activity in urine and in exhaled air. Formation of stronger and less soluble complexes of the ethylenebis(dithiocarbamate) (EBDC) anion and its degradation products were responsible for this and the presence of certain naturally occurring cations in food might reduce the amount of EBDC residues absorbed. This depression of the absorption rate must be considered in estimating hazards due to low levels of maneb residues in food.