The European Food Safety Authority’s (EFSA’s) Panel on Contaminants in the Food Chain (CONTAM Panel) has issued a scientific opinion assessing the health risks of acute and chronic dietary exposure to chlorate, “a byproduct when using chlorine, chlorine dioxide or hypochlorite for the disinfection of drinking water, water for food production and surfaces coming into contact with food.” At the request of the European Commission, the opinion considers the presence of chlorate in both drinking water and food, setting “a tolerable daily intake (TDI) of 3 micrograms per kg (μg/kg) of body weight per day for long-term exposure to chlorate in food,” with “a recommended safe intake level for a daily intake (called the ‘acute reference dose’) of chlorate of 36 μg/kg of body weight per day.”

After reviewing data collected by the EFSA Evidence Management Unit, the CONTAM Panel identified drinking water as “the main average contributor to [] chronic dietary exposure,” but singled out frozen food commodities as having “the highest levels of chlorate within each food group.” In particular, the agency links chronic chlorate exposure to iodine deficiency in infants, toddlers and children younger than 10 years, the groups in which the highest exposure estimates exceeded the TDI. At the same time, however, the opinion notes that introducing “a maximum residue level (MRL) of 0.7 mg/kg for all foodstuffs and drinking water would only minimally reduce acute/chronic exposures and related risks.”

“Long-term exposure to chlorate in food, particularly in drinking water, is a potential health concern for children, especially those with mild or moderate iodine deficiency,” states EFSA in a June 24, 2015, news release. “But the total intake on a single day even at the highest estimated levels is unlikely to exceed the recommended safe level for consumers of all ages.”