Iodate and Perchlorate in Bottled Water: Methods for Discovery and Impact on Humans

This chapter presents a review of the occurrence of iodate and perchlorate in bottled water. Contamination of water with perchlorate has become a major environmental and health concern in recent years, as toxicological associations of perchlorate to abnormal endocrine functions have emerged. Iodate and perchlorate are oxyhalide anions that are present in water and originate from natural and anthropogenic sources. Iodate is rapidly formed when water-containing iodide is disinfected with ozone. Perchlorate is a common contaminant that is formed during the manufacture and use of munitions and fireworks. More recently, perchlorate has been shown to form and accumulate in sodium hypochlorite solutions used for water disinfection. Therefore, iodate and perchlorate have the propensity to contaminate bottled water, from both contamination of source water and from the use of disinfectants during the treatment process. Perchlorate and iodate detection in water has improved significantly in recent years, due to improvements in analytical methodology. Perchlorate and iodate have been detected in bottled water, but not in significant amounts. In mammals, it has been shown that perchlorate is a competitive inhibitor of thyroidal iodide uptake; hence drinking water perchlorate contamination has been associated with abnormal newborn thyroid function in humans. The co-occurrence of iodate/iodide with perchlorate is of great importance. In iodide-deficient populations, the impact of perchlorate on the thyroid will be significantly more profound. Therefore, modern analytical methodologies capable of providing simultaneous iodate and perchlorate identification and quantification are critical.