Question:
The EPA's provisional drinking water equivalent level (DWEL) for perchlorate is 4 - 18 parts per billion (ppb). Is this the allowable level of perchlorate in bottled water?

Answer: The government is investigating the ways that plants take up perchlorate. Perchlorate might get into plants when they are irrigated with perchlorate-containing water or when plants are grown in soil that has been previously exposed to perchlorate-containing water or fertilizer. Perchlorate in water used for food processing might also be a source of contamination in finished food products.

FDA has placed high priority on developing analytical methods for measuring perchlorate in foods and plans to conduct surveys of foods that are suspected to contain perchlorate, such as lettuce, particularly from regions where water sources are believed to be contaminated with perchlorate, to determine the presence and levels of perchlorate in these types of foods.