Toxicology, occurrence and risk characterisation of the chloropropanols in food: 2-monochloro-1,3-propanediol, 1,3-dichloro-2-propanol and 2,3-dichloro-1-propanol.

Great attention has been paid to chloropropanols like 3-monochloro-1,2-propanediol and the related substance glycidol due to their presence in food and concerns about their toxic potential as carcinogens. The other chloropropanols 2-monochloro-1,3-propanediol, 1,3-dichloro-2-propanol and 2,3-dichloro-1-propanol have been found in certain foods, but occurrence data are generally limited for these compounds. 1,3-dichloro-2-propanol has the most toxicological relevance showing clear carcinogenic effects in rats possibly via a genotoxic mechanism. The dietary exposure to 1,3-dichloro-2-propanol is quite low. Calculated "Margins of Exposure" values are above 10,000. It is concluded that the 1,3-dichloro-2-propanol exposure is of low concern for human health. The toxicology of 2,3-dichloro-1-propanol has not been adequately investigated. Its toxicological potential regarding hepatotoxic effects seems to be lower than that of 1,3-dichloro-2-propanol. Limited data show that 2,3-dichloro-1-propanol occurs only in trace amounts in food, indicating that exposure to 2,3-dichloro-1-propanol seems to be also of low concern for human health. The dietary 2-monochloro-1,3-propanediol burden appears to be lower than that of 3-monochloro-1,2-propanediol. An adequate risk assessment for 2-monochloro-1,3-propanediol cannot be performed due to limited data on the toxicology and occurrence in food. This article reviews the relevant information about the toxicology, occurrence and dietary exposure to the chloropropanols 2-monochloro-1,3-propanediol, 1,3-dichloro-2-propanol and 2,3-dichloro-1-propanol.