January 9, 2011

Getting Rocket Fuel Out Of Drinking Water

California has been making some real progress on important drinking water issues in recent weeks. Last week I blogged about the newly proposed Public Health Goal (PHG) for cancer-causing hexavalent chromium in drinking water. Today, the State proposed a welcome new PHG for another important contaminant -- perchlorate. The new proposal "“ at 1 part per billion (ppb) "“ is significantly more stringent than the prior California standard of 6 ppb and is designed to protect infants and children.

Perchlorate is a toxic salt used in rocket fuel, fireworks, road flares and other explosives. Unlike hexavalent chromium, it's not a potent carcinogen; instead its effects are much more subtle and insidious. Perchlorate blocks the uptake of essential iodine into the thyroid gland, thereby disrupting production of hormones essential for regulating human metabolism. In the fetus and infant, these hormones also have a key role in brain development. Oh, did I mention that perchlorate also blocks the movement of iodine across the placenta and also the delicate transportation mechanism that enriches breast milk with iodine?

The special susceptibility of young infants is the main reason why the new perchlorate PHG is lower than the last one. The prior regulation neglected to consider the breastfed infant, and also the significant water consumption of bottle-fed infants. In addition, people with nutritional iodine deficiencies are at much greater risk of adverse effects from perchlorate. That's why getting enough dietary iodine "“ from seafood or (less ideally) from iodized salt "“ is so important for pregnant women and children.

There is no Federal drinking water standard for perchlorate. In April 2008, the EPA Science Advisory Board Drinking Water Committee (which I served on at the time) recommended that EPA prioritize perchlorate for a new standard. Instead, in late-2008, EPA under the Bush Administration proposed to not regulate this chemical at all. The Science Advisory Board responded with a strong letter stating that: "Given perchlorate's wide occurrence and well-documented toxicity to humans," EPA should prioritize this chemical for regulation.

Since that time we have all simply been waiting.

We are still waiting for the long-overdue decision from U.S. EPA about whether they will even start the process of setting a drinking water standard for perchlorate. The EPA decision has been stalled awaiting approval in the Office of Management and Budget for more than three months. Since EPA hasn't issued a new drinking water standard since the last century, it's high time that the Feds get moving on this high-priority chemical.

Thankfully, California isn't waiting.  California's Office of Environmental Health Hazard Assessment (OEHHA) is showing scientific and policy leadership on this important issue. They deserve congratulations on their work so far, but the job isn't done "“ California needs to move forward quickly to finalize an updated standard that protects infants and children.


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