Toxicological evaluation and limit values for Methyl-tertiary-butyl ether (MTBE), Formaldehyde, Glutaraldehyde, Furfural

7. Evaluation

The critical effect of furfural after oral administration to laboratory animals is the hepatotoxicity observed in subchronic and chronic studies. Male rats appeared to be more sensitive to the cytotoxic effects than female rats and mice. In contrast hereto, mice appeared to be more sensitive to the hepatocarcinogenic effects than rats. For mice, the carcinogenic effects were observed at higher dose levels (175 mg/kg/day) than the cytotoxic effects (100 mg/kg/day) and male mice appeared to be more sensitive than female mice.

In hamsters, no indications of carcinogenic effects were observed after exposure to furfural vapours by inhalation for one year. However, that could be due to the relatively short period of exposure.

Furfural exhibits an inconsistent pattern of genotoxicity, being generally negative in bacterial assays, positive in some eukaryotic systems in vitro, and negative in some in vivo tests. Based on these data, no conclusion whether furfural is a genotoxic substance can be drawn. However, the negative response in in vivo tests could indicate that furfural is a non-genotoxic substance.

In conclusion, furfural is considered to be a non-genotoxic substance. The critical effect after oral administration is considered to be hepatotoxicity and after inhalation to be the irritation of eyes and mucous membranes observed in humans.