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New Studies Support MassDEP's Perchlorate Standards  Two new studies support the Massachusetts Department of Environmental Protection's 2 ppb drinking water standard for perchlorate, a chemical found in certain explosives, fireworks, flares and munitions.
Researchers at the Centers for Disease Control (CDC) sampled perchlorate levels in approximately 2,800 people as part of a national survey. Perchlorate was detected in most of the samples, indicating widespread exposures.
The CDC researchers also found an association between perchlorate levels and altered thyroid hormones in a subset of women with low dietary iodine intake. Thyroid hormones are necessary for normal growth and neurological (brain) development of fetuses, infants and children.
The CDC study, published by Environmental Health Perspectives in September 2006, supports the conclusions of MassDEP's determination that perchlorate levels in drinking water should not exceed 2 ppb in order to protect public health.
A second study by the National Science Foundation (NSF) found perchlorate in sodium hypochlorite (bleach) solutions used to disinfect drinking water. NSF estimated that the use of these solutions could lead to average perchlorate levels in drinking water of approximately 2 ppb.
This new information is consistent with data previously collected by MassDEP and supports the Department's risk management decision to set the perchlorate drinking water standard at 2 ppb.
The NSF and MassDEP data indicate that sodium hypochlorite used to disinfect water should be carefully managed to minimize perchlorate inputs. In particular, perchlorate levels were found to be higher in aged solutions and thus may be a concern for water systems that store sodium hypochlorite for longer periods of time (greater than 30 days), or have residual levels of aged chemical in storage tanks, which may contaminate new shipments. NSF is moving to require perchlorate standards for disinfection products.
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