Many controversial contaminants recently in the news, such as perchlorate, formaldehyde, and the gasoline additive MTBE, are included on a list of 104 pollutants that are known or likely to be found in drinking water, and which EPA is asking for public comments on as it decides whether and how to regulate them. The agency is also taking comments on the new process it used to whittle down the original list of about 7,500 substances it considered for addition to its list of 87 regulated drinking water contaminants. The 90-day public comment period ends May 21, 2008.

• Federal Register notice of Feb. 21, 2008. [2]

Other substances under review include pesticides, industrial chemicals, disinfection byproducts, and pathogens such as acetaldehyde, hydrazine, cobalt, ethylene glycol, nitroglycerin, permethrin, strontium, and select forms of microbes such as Salmonella, Legionella, and Helicobacter.

If EPA chooses to regulate any of the 104 substances, it will have to begin a formal rulemaking process for each. It likely will be several years before any might be added to those that each utility must track and report on annually in its Consumer Confidence Report.

For more information on the review process for the 104 substances, see EPA's Contaminant Candidate List 3 [3] (which includes many links to other drinking water contaminant information).

Among the many organizations that will be following this process closely are:

• American Water Works Association. [4]
• Association of Metropolitan Water Agencies. [5]
• Clean Water Action. [6]