• Open Access

Risks for public health related to the presence of chlorate in food


  • EFSA Panel on Contaminants in the Food Chain (CONTAM)

  • Panel members: Diane Benford, Sandra Ceccatelli, Bruce Cottrill, Michael DiNovi, Eugenia Dogliotti, Lutz Edler, Peter Farmer, Peter Fürst, Laurentius (Ron) Hoogenboom, Helle Katrine Knutsen, Anne-Katrine Lundebye, Manfred Metzler, Antonio Mutti (as of 6 October 2014), Carlo Stefano Nebbia, Michael O'Keeffe, Annette Petersen (as of 6 October 2014), Ivonne Rietjens (until 2 May 2014), Dieter Schrenk, Vittorio Silano (until 21 July 2014), Hendrik van Loveren, Christiane Vleminckx, and Pieter Wester.
  • Correspondence: contam@efsa.europa.eu
  • Acknowledgement: The Panel wishes to thank the members of the Working Group on chlorate in food: Diane Benford, Helle Katrine Knutsen, Jean-Charles Leblanc, Tanja Schwerdtle and Christiane Vleminckx for the preparatory work on this scientific opinion and the hearing expert: Rudolf Pfeil and EFSA staff: Davide Arcella, Katleen Baert, Marco Binaglia, Barbara Dörr, Jose Angel Gomez Ruiz, Hans Steinkellner and Enikő Varga for the support provided to this scientific opinion. The Panel acknowledges all European competent institutions that provided occurrence data on chlorate and supported the data collection for the Comprehensive European Food Consumption Database, as well as the stakeholders that provided toxicity and food processing studies.
  • Adoption date: 3 June 2015
  • Published date: 24 June 2015
  • Question number: EFSA-Q-2014-00534
  • On request from: European Commission


Following a request from the European Commission, the risks to human health related to the presence of chlorate in food were assessed by the EFSA Panel on Contaminants in the Food Chain (CONTAM Panel). The presence of chlorate in food can arise from the use of chlorinated water for food processing and the disinfection of food-processing equipment. Inhibition of iodine uptake in humans was identified as the critical effect for chronic exposure to chlorate. A tolerable daily intake (TDI) of 3 µg chlorate/kg body weight (b.w.) was set by read-across from a TDI of 0.3 µg/kg b.w. derived for this effect for perchlorate, multiplied by a factor of 10 to account for the lower potency of chlorate. Formation of methaemoglobin was identified as the critical acute effect of chlorate. An acute reference dose (ARfD) of 36 µg chlorate/kg b.w. was derived from a no-observed-effect-level for chlorate in a controlled clinical study. Chronic exposure of adolescent and adult age classes did not exceed the TDI. However, at the 95th percentile the TDI was exceeded in all surveys in ‘Infants’ and ‘Toddlers’ and in some surveys in ‘Other children’. Chronic exposures are of concern in particular in younger age groups with mild or moderate iodine deficiency. Mean and 95th percentile acute exposures were below the ARfD for all age groups indicating no concern. Based on the current practices in food industry, application of a hypothetical maximum residue limit (MRL) of 0.7 mg/kg for all foodstuffs and drinking water would only minimally reduce acute/chronic exposures and related risks. Assuming chlorate concentrations of 0.7 mg/kg for all foods and drinking water consumed in a day, acute exposures would increase by up to about 5-fold and the ARfD be exceeded at mean estimates in ‘Infants’ and ‘Toddlers’ and at 95th percentile also in ‘Other children’ and ‘Adults’.