Teratogenic effects of the fungicide maneb on chick embryos.

The teratogenicity of a commercial formulation of the fungicide maneb (Maneb 80, containing 80% manganese ethylenebisdithiocarbamate and 20% inert ingredients) in chick embryos was evaluated. Unincubated eggs (157-207 per treatment group) were immersed in 0.5, 1.5, 4.5, or 13.5 g/liter maneb aqueous solutions for 30 sec. Two control groups were used: one group of 200 eggs was immersed in tap water and a second group of 205 eggs was immersed in a solution of the inert ingredients (sodium lignin sulfonate and n-butylnaphthalene sulfonate) at the concentration present in the 13.5 g/liter maneb solution. Eggs were then incubated for 19 days. A single treatment with maneb was teratogenic at all concentrations tested, producing mainly unilateral lower limb deformities. No adverse effects on development were noticed after exposure to the inert ingredients.