Embryotoxic Effects of Phtalic Acid Derivatives, Phosphates and Aromatic Oils Used in the Manufacturing of Rubber on Three Day Chicken Embryos

Abstract

Several chemicals that are used for manufacturing of rubber were tested for embryotoxicity on 3-day chicken embryos. Cyclohexylthiophthalimide was the most potent of the chemicals, with an ED50 value for the total embryotoxic effect 0.04 .mu.mol (10 .mu.g)/egg. Phthalic anhydride was about ten times less potent, having the total ED50 for total embryotoxicity 0.38 .mu.mol (56 .mu.g) per egg. Two esters of phthalic acid, dibutylphthalate and butylbenzylphthalate, were relatively impotent, with ED50 values of about 33 .mu.mol and 27 .mu.mol/egg, respectively. Two phosphates, tricresylphosphate and synthetic arylphosphate, were not potent embryotoxic agents in the chick embryos. They had ED50 values of 7.0 .mu.mol (2.6 mg)/egg and 9.5 mg/egg, respectively. NaH2PO4 had an ED50 of 11 .mu.mol/egg. Three types of oils were also tested. A mixture known as highly aromatic oils was the most potent, with an ED50 of 31 .mu.g/egg. Low aromatic, paraffin base oils was the next potent, with an ED50 of 87 .mu.g/egg, while naphthenic oils had an ED50 of 480 .mu.g/egg. Cyclohexylthiophthalimide and phthalic anhydride caused malformations at high frequency. The oils and tricresylphosphate appeared to be efficient teratogens.