Expanded testing found it to be a drinking water contaminant in southern California, too.
Perchlorate interferes with the thyroid gland's uptake of iodine to produce thyroid hormones.
Normal body metabolism requires thyroid hormones, as do normal prenatal and postnatal development and growth. Subsequently, perchlorate was found in drinking water in other parts of the country. The US EPA Office of Water's perchlorate website presents information on federal activities. Toxicological Review and Risk Characterization Based on Emerging Information , perchlorate originates as a contaminant in ground and surface waters from the dissolution of ammonium, potassium, magnesium, or sodium salts. Perchlorate also appears to be associated with certain types of fertilizers.