Ecotoxicological profile of xylenes. Working party on ecotoxicological profiles of chemicals

The xylenes (o, m, p), which are produced in large amounts and widely used, must be considered as environmental contaminants, as they have been identified in the atmosphere of many countries. Their acute and chronic toxicity in mammals is moderate. Mutagenic and teratogenic properties can be excluded. Carcinogenic potential has been at present inadequately studied. In man some disturbances are evident at the concentration of 45 ppm. Hepatic metabolism is a valid process of detoxification and its high rate limits the risk of accumulation of the xylenes in adipose tissue. Ecotoxicological data refer almost exclusively to water. No long-term tests have been made. However, the high volatility, elevated elimination, and the low factor of accumulation suggest the impact on aquatic environment should be limited. Xylenes are easily biodegraded by many microorganisms. Photoxydation is one of the main degradation processes, responsible for the disappearance of the xylenes from the atmosphere.