Effects of methylene chloride, trichloroethane, trichloroethylene, tetrachloroethylene and toluene on the development of chick embryos.

Toluene and 5 aliphatic chlorinated hydrocarbons of wide industrial use were injected into the air space of fertilized chicken eggs at 2, 3 and 6 days of incubation. The embryotoxicity was evaluated as survival and death incidences after 14 days of incubation, and also the weights and lengths of the embryos were recorded. The approximate LD50 value for trichloroethylene and trichloroethanes varied between 50 and 100 mumol/egg while for toluene, tetrachloroethylene and methylene chloride it was over 100 mumol/egg. Macroscopic malformations of various kinds were produced with doses of 5-100 mumol/egg. The teratogenic potential of the tested compounds decreased in the following order: 1,1,1-trichloroethane greater than trichloroethylene greater than methylene chloride, tetrachloroethylene, 1,1,2-trichloroethane greater than toluene greater than olive oil control.