OCCURRENCE OF PERCHLORATE AT WATER TREATMENT PLANTS OF THE TONE RIVER BASIN IN JAPAN

摘要

Perchlorate is used in missile/rocket propellants and also in various industrial products. Perchlorate is known to interfere with iodine uptake by the thyroid gland. In 2005, the United States Environmental Protection Agency (USEPA) has established 0.7 μg/kg/day as the reference dose (RfD) for perchlorate and announced 24.5 μg/L as its drinking water equivalent level (DWEL). Since the late 1990s, perchlorate has been detected in water, milk and foods in many places in the U.S.. In the case of Japan, the occurrence of perchlorate in the environment was not investigated; however, more recently, it was reported that the river and tap waters in the Tone River Basin located in the east area in Japan were contaminated by perchlorate by authors. This indicated that it was important to understand the occurrence of perchlorate in drinking water of the area in detail. Therefore, in this study, we investigated the occurrence of perchlorate at water treatment plants of the Tone River Basin.