Massachusetts Proposes First-in-the-Nation Drinking Water and Cleanup Standards of 2 ppb for the Chemical Perchlorate

In March 2006, the Massachusetts Department of Environmental Protection (MassDEP) announced the first-in-the-nation drinking water and waste site cleanup standards of 2 parts per billion (ppb) for the chemical perchlorate, which has been found in drinking water sources at 10 locations across the state. Perchlorate was first detected in Massachusetts in 2002 in the aquifer under the Massachusetts Military Reservation on Cape Cod, when it was found to be moving toward drinking water wells in the town of Bourne. In 2004, MassDEP required all drinking water systems in the state to test for the presence of perchlorate in their drinking water sources. Specifically, MassDEP instituted interim guidelines effective February 13, 2004. Those guidelines required water systems to periodically sample for perchlorate. The MassDEP interim guidelines noted that the sensitive subpopulations of pregnant women, infants, children under age 12 and individuals with untreated hypothyroidism should not drink water that contains more than 1 ppb of perchlorate. The general population is advised not to drink the water if levels exceed 18 ppb. Test results indicated perchlorate above the interim state advisory level at sites in Chesterfield, Southbridge, Hadley, Williamstown, Boxborough, Millbury, Westford, Boxford, Tewksbury and Westport, and those sites were required by MassDEP to take specific actions to address the contamination.

Perchlorate is an emerging contaminant that has raised a red flag for environmental agencies and public health officials across the country. No federal standards regulating perchlorate levels in drinking water currently exist. The conservative standards adopted by MassDEP ensure that the water is safe to drink for all citizens of the Commonwealth, including sensitive populations. Perchlorate disrupts normal function of the thyroid gland and could affect pregnant women and their developing fetuses, infants, children and individuals who have untreated low levels of thyroid hormones. The adverse health effects associated with perchlorate exposure are expected to be similar to those caused by iodine deficiency. MassDEP proposed the 2 ppb standard based on its review of the scientific data available on perchlorate, including analysis performed by independent scientists at the National Academy of Sciences.

Others, including from the United States Department of Defense responsible for the cleanup of the Military Reservation, think the standard is much too conservative. Because perchlorate is a chemical that can be found in blasting agents, fireworks, and military munitions, the defense industry is particularly concerned about the clean-up standard. The defense industry relies on a January 2005 report by the National Academies’ National Research Council on the health effects of perchlorate which indicates that a daily ingestion of up to 0.0007 milligrams per kilogram of body weight can occur without adversely affecting the health of even the most sensitive populations. That amount is more than 20 times the “reference dose” proposed by the U.S. Environmental Protection Agency (EPA) in a 2002 draft risk assessment, and is substantially higher than the standard proposed in Massachusetts.

The proposed regulations require parties responsible for perchlorate contamination to clean up the contamination and for all drinking water supplies to contain no more than 2 ppb of perchlorate. By contrast, EPA’s cleanup standard for federal facilities is 24 ppb. The regulations also require regular testing for perchlorate in all public water systems.

Until Massachusetts concludes its public hearing and rulemaking process, it is uncertain whether its proposed standard of 2 ppb will stick, but if MassDEP has its way, the Commonwealth will surpass California in environmental conservatism on this issue.