Chlorate and perchlorate: more stringent regulations

Chlorate (ClO3 ions) containing preparation are widely used total – non selective – herbicides. Although their application was banned in the European Union as early as in 2011, still a substantial quantity is left over in the environment and as the chlorination of waters and the use of different disinfectants becomes more and more frequent, the replenishment of chlorate residues is continuous. Since laboratories often detect out of specification levels of chlorate residues from food, the Commission of the European Union amended the regulation containing the maximum permissible levels of chlorate residues in food items with effect of 1 July 2020. From the effective date of the regulation, regular testing of food and drinking water will be even more important than before.

Based on the food safety and environmental toxicological data chlorate residues left over from herbicide compounds have an adverse impact on warm blooded animals, including man. The best known property of the general characteristics of chlorates is the destruction of haemoglobin in the blood (methemoglobinemia) and the triggering of various renal failures.

Based on the decision made by the experts of the Commission of the European Union the widely used agricultural herbicide, chlorate was banned in 2011 and withdrawn from commercial circulation.

Perchlorate ions have a similar effect to that of chlorate ions. These ions appear in the environment primarily as contaminations originating from geochemical sources and industrial activities –Dr. Tamás János Szigeti, business development director of the WESSLING Hungary Kft. independent laboratory said to Laboratorium.hu.

Perchlorate (ClO4-) ions may also be generated in the course of the disintegration of hypochlorite products used for general disinfection purposes (they can primarily be connected to the chlorination of waters), but perchlorate may also be generated in certain rocks by way of natural geochemical processes. Maximum permitted (tolerable) limits of perchlorates in food is controlled by Regulation (EC) No 2020/685. Maximum permitted levels move in the 0.01 – 0.75 mg/kg range pending on the type of food. Perchlorates inhibit among others iodine intake by food of warm blooded living beings – including man – and hence they disturb the functional operation of the thyroid gland.

In times of the corona virus epidemic the cheapest and most efficient procedure usually to disinfect various water systems and easily contaminated surfaces is the use of some kind of a disinfectant with chlorine contents – such as sodium hypochlorite (Hypo) or in case of water based systems the chlorine dioxide. Please note that in the practices of water utility companies the piping system and the drinking water itself must be regularly disinfected anyway, therefore the organisations operating water utilities can not be blamed for the chlorate ions which appear in the drinking water occasionally in a detectable amount. This is why it is necessary to keep an eye  on the chlorate quantities produced in the course of the disinfection process by a monitoring system on an ongoing basis.

This is why Regulation (EU) 2020/749 of the European Commission will take effect within the territory of the EU on 1 July 2020, amending the tolerable chlorate residue levels specified in Annex No 3 to Regulation (EC) 396/2005.