Risk Policy Report, Maria Hegstad
Published January 29, 2008
Environmentalists and some House Democrats are pointing to the results of a new Food and Drug Administration (FDA) study showing widespread perchlorate contamination in food as evidence of a sufficient risk to warrant EPA's setting a national drinking water standard for the rocket fuel chemical that is more stringent than most state-set standards.
However, the lawmakers and activists are divided over how strict a standard EPA should eventually set.
Nevertheless, the new push for strict perchlorate cleanup standards is likely to draw concerns from potentially liable industry parties and the Department of Defense (DOD), which is already fighting plans by Massachusetts and other states to adopt strict perchlorate cleanup levels.
The newly released FDA research, known as the Total Diet Study, is the first comprehensive look at perchlorate in food, and shows a wide variety of contaminated food.
The study, published earlier this month in the Journal of Exposure Science and Environmental Epidemiology, found that across a wide range of age groups, perchlorate exposure from food consumption ranged from 0.08 to 0.39 micrograms per kilogram (ug/kg) body weight per day. For two-year old children, the study found an average intake from food of 0.35 -- 0.39 ug/kg. The study is available on InsideEPA.com.
EPA noted in the Federal Register last May that the study results could aid the agency in determining whether to set a drinking water standard, known as a maximum contaminant level (MCL), because it would for the first time include data for several key food groups, including meat, grains and several types of vegetables. EPA previously has relied on Total Diet Study data to set MCLs for other contaminants.
Perchlorate is widely used as a stabilizer in military munitions and rocket fuel, making it a crucial chemical for the DOD, National Aeronautics and Space Administration and their contractors. It is also widespread in the environment, contaminating drinking water supplies in at least 26 states, according to the Government Accountability Office. Concerns about potential health risks and its presence in drinking water initially led EPA to develop a draft risk level of 1 ppb.
DOD challenged that standard, leading to a National Academy of Sciences review that prompted EPA to set a safe exposure level, or reference dose (RfD) of 0.7 ug/kg. EPA also translated the RfD into a 24.5-ppb guideline for cleanup decisions.
However, environmentalists and other agency critics have urged the agency to set an enforceable MCL for perchlorate for years, citing studies that link the chemical to interference with thyroid function. Impairment of thyroid function in pregnant mothers may impact the fetus and result in such effects as behavior changes, delayed development and decreased learning capability.
The ability to determine all the sources of perchlorate ingestion is key to setting an MCL, which takes into account both food and water. In setting an MCL, EPA uses a factor known as relative source contribution, which generally holds that if food is the primary way people are exposed to a contaminant, then the MCL must be very stringent in order to limit overall exposure.
But EPA has delayed making any decision on whether to set an MCL, saying last year it was still seeking additional exposure data on the sources of perchlorate. An EPA official said in a Jan. 25 statement the agency will decide before the end of 2008 whether to set an MCL.
In the absence of EPA action, many states have moved to set their own standards. Among the states that have acted so far, Massachusetts has set a 2 ppb standard, the strictest level set so far, while New Jersey and California are adopting slightly weaker standards.
House Democrats, led by Reps. Hilda Solis (D-CA) and Albert Wynn (D-MD), are also trying to push a bill through Congress that would require EPA to set the perchlorate MCL by a date certain. While the bill, H.R. 1747, passed out of the House Energy & Commerce Committee in 2007, a committee aide says it has not yet been placed on the full committee's calendar for action.
Now environmentalists and House Democrats are arguing that the new FDA data demonstrates that EPA needs to set a standard even stricter than levels set by most states.
Democrats on the House Energy & Commerce Committee issued a statement in response to the study findings saying that Massachusetts is the only state with a perchlorate standard low enough to protect 2-year-olds from "daily unsafe exposure to perchlorate when combined food and water exposures are considered."
"When the average child consumes perchlorate contaminated drinking water either alone or with perchlorate contaminated food, the amount of ingested perchlorate has the potential to exceed nearly every one of the proposed or final drinking water standards, except the Massachusetts standard of two ppb, thereby subjecting them to the adverse health effects of perchlorate," the Democrats' Jan. 22 statement says.
Environmentalists, meanwhile, are arguing that even Massachusetts' standard is not strict enough. "We need [a standard of] less than 1 ppb, given this new data, given that food contamination is widespread," a source with the Environmental Working Group, told Risk Policy Report. The source notes that the FDA study shows that 2-year-old children are consuming half of EPA's RfD from food alone, making it essential that EPA's upcoming MCL needs to limit harmful exposure.
