Understanding the presence of chlorate and perchlorate in food: potential risks, regulatory measures and analytical challenges

Introduction

With heightened public awareness of disinfection due to the recent pandemic, chlorate and perchlorate have become important contaminants for health and safety discussions. Chlorate and perchlorate are oxyanions with the chlorine atom in the +5 and +7 oxidation state respectively. Research into these compounds is still ongoing, but a wide number of uses and potential health risks have already been determined. Chlorate is known to be an effective herbicide and is mainly used in the production of disinfectants.¹ Perchlorate is predominately used as an oxidiser in solid fuels and is commonly seen in rocket propellant, fireworks, and other munitions. Perchlorate can also be present in road flares, lubricating oils, matches, aluminium refining, rubber manufacturing, paint and enamel manufacturing, leather tanning and as a dye mordant.² As alternatives for some of these uses are not currently available, risk assessment and monitoring programmes for these compounds is a critical safety objective.

Health risks

Chlorate and perchlorate have been associated with adverse effects to iodide uptake in the thyroid. This can lead to inhibition of thyroid hormone production and is most dangerous to those with iodine deficiency and to infants and pregnant women. Thyroid hormones are important for proper growth and development in foetuses and can lead to improper development of the central nervous system if left untreated. Chronic exposure to chlorate has also been shown to have negative effects on red blood cells.³