That is good and bad news for the Defense Department and military contractors battling accusations that they have polluted groundwater with perchlorate, a primary component of rocket fuel.
The fact that perchlorate -- a salt comprising a chlorine atom and four oxygen atoms -- occurs naturally makes it difficult to draw simple conclusions about whether to regulate it or remove it from the drinking-water supplies of at least 35 states and the District of Columbia.
On the other hand, that perchlorate is more widespread than previously thought suggests to proponents of federal water regulations that there is all the more need to regulate its presence in drinking water.
The debate over perchlorate now moves to U.S. EPA, which requested public comments this week on possible regulation of perchlorate in drinking water. EPA is asking whether there are alternative ways to evaluate if perchlorate occurs at a frequency and at levels to cause health concerns and whether a national drinking-water regulation would lead to a "meaningful opportunity for health risk reduction."
The agency said it is particularly concerned about the possible impact of perchlorate on the health of very young children. Perchlorate has been known to inhibit the thyroid gland's iodine uptake and interfere with fetal development at high doses.
"It is critically important to protect sensitive populations, particularly infants and young children, from perchlorate in drinking water," EPA Administrator Lisa Jackson said in a statement. "As we re-evaluate the science around perchlorate, we will seek public input before making a regulatory determination based on the best science."
But the science behind perchlorate has grown complicated in recent years. Notably, researchers were stunned last year when they discovered perchlorate on Mars.
"The last thing anyone expected was to have almost all of the chloride in Martian soil as perchlorate," said Dave Stonestrom, a research hydrologist with the U.S. Geological Survey.
The Martian perchlorate was formed naturally, Stonestrom said, but no one can say whether Martian perchlorate is found all around the planet or whether its formation is ongoing or is a relic from past conditions.
New technology sparks regulatory debate
The debate over perchlorate began after EPA began noticing it in groundwater at certain California Superfund sites in the 1980s, said Kevin Mayer, the Superfund project manager at the EPA Region 9 office in San Francisco.
There were huge gaps then in what was known about the chemical's toxicology and detection.
But in 1997, scientists developed a way of detecting concentrations of the chemical at 4 parts per billion, a level far lower than levels detectable previously. Almost overnight, it seemed, perchlorate was turning up everywhere, including the Colorado River, which provides water for 20 million people.
"It was pretty clear by the middle of 1997 that Region 9 had a big issue on its hands, bigger than the Superfund program was set up to deal with on a site-by-site basis," Mayer said. "We needed some really good science."
Science was critical because DOD and other parties that were being accused of polluting water and soil with perchlorate were arguing that they were not responsible for contamination nor for the extremely expensive cleanups.
"A lot of people like to know whose perchlorate it is when they find perchlorate where it isn't supposed to be," said Andrew Jackson, an engineering professor and perchlorate researcher at Texas Tech University.