Follow up to previous postings on perchlorate contamination of drinking water, today “EPA issued an interim health advisory to assist state and local officials in addressing local contamination of perchlorate in drinking water. The interim health advisory level of 15 micrograms per liter (µg/L), or parts per billion (ppb), is based on the reference dose recommended by the National Research Council (NRC) of the National Academy of Sciences (NAS). The Agency is also seeking advice from the NAS before making a final regulatory determination on whether to issue a national regulation for perchlorate in drinking water.”