Two states act on perchlorate in drinking water

Following Massachusetts' lead, California on Aug. 28 proposed a limit of 6 parts per billion for perchlorate in drinking water. In late July, Massachusetts set a 2-ppb standard, becoming the first state in the nation to set such a limit. The states' standards will help guide cleanup of perchlorate-tainted aquifers. As they took their regulatory steps, Massachusetts and California officials considered a 2005 report by the National Research Council suggesting a safe dose-but not a drinking-water standard-for the chemical (C&EN, Jan. 17, 2005, page 13). Although EPA has adopted that NRC safe-dose number, the agency has not proposed a national drinking-water standard for perchlorate. The chemical, which is used in fireworks, explosives, and road flares, as well as rocket fuel, interferes with iodine uptake by the thyroid gland.