Studies on the toxicity of petroleum waxes

Abstract

1. 1. The experimental approach to the problem of determining the safety of petroleum waxes as incidental additives to human food is discussed. 2. 2. Thirty-six samples of petroleum wax were analyzed for polycyclic aromatic hydrocarbons. Eight samples contained identifiable hydrocarbons. Benz[ a] anthracene, benzo[ e]pyrene, chrysene, flouranthene, pyrene, and triphenylene were identified. The highest concentration of polycyclic hydrocarbon was 0.64ppm. No correlation was observed between polycyclic aromatic hydrocarbon content and any physical characteristic of the waxes, including crystalline form. 3. 3. The elution of polycyclic aromatic hydrocarbons added to petroleum waxes by milk, skimmed milk, and butter fat has been studied by absorption spectroscopy and using C 14-labeled hydrocarbon. Both the fat and protein components of milk were responsible for the elution. The four polycyclic aromatic hydrocarbons studied were eluted at comparable rates. Elution from paraffin wax was considerably greater than from microscrystalline wax. No relation was found between elution of polycyclic aromatic hydrocarbon and oil content of wax. Very little of the eluted material remained as free hydrocarbon in the milk. The elution in the gut of rats and mice of dibenz[ a,h]anthracene added to waxes has been studied by absorption spectroscopy and using labeled hydrocarbon. The proportion of dibenzanthracene eluted from the wax was high, although most of the eluted material did not pass into the animal. Direct measurement of the radioactivity in the carcass showed that 6–20% of the radioactive material in the wax had passed through the intestinal wall, but none of this was present as the free hydrocarbon. 4. 4. Five petroleum waxes were tested by repeated skin application in benzene solution to mice and rabbits. In addition one of the test waxes was fractionated and its aromatic and nonaromatic components were tested separately on mice, also by repeated skin applications. Solvent-treated controls were kept. No carcinogenic effect was detected. 5. 5. Five petroleum waxes were tested in mice by subcutaneous implantation in disk form. Fibrosarcomas developed around the implants with incidences correlated to the melting points of the waxes. In addition, one of the test waxes was fractionated and its aromatic and nonaromatic components were tested separately; the same wax was also tested subcutaneously in powdered form. The findings indicate that the subcutaneous sarcomas occurred as a result of the physical rather than the chemical properties of the materials. 6. 6. Five petroleum waxes were tested by feeding in rats at a 10% level in the diet for a period of two years, following which the rats were observed until their death. No carcinogenic or toxic effect was detected. 7. 7. Untreated groups of Swiss mice of both sexes and of Sprague-Dawley rats of both sexes were observed for their whole life span and then submitted to complete autopsy and to histologic examination. All the tumors observed are reported. 8. 8. The conclusion drawn from the results of the chemical and biological experiments is that no carcinogenic or other toxic hazard has been demonstrated in petroleum waxes used in food packaging or other food applications.