Children’s health panel slams EPA’s perchlorate goal
The current policy of assuming that all exposures come from drinking water doesn’t account for perchlorate found in lettuce or breast milk, the advisors write.
The U.S. EPA’s new perchlorate cleanup goal isn’t supported by science, fails to protect children’s health, and needs to be lowered [702KB PDF], according to an agency scientific advisory panel. The goal, revised in January by the EPA’s Office of Solid Waste, is at least 4 times less stringent than similar goals recently proposed by 3 states.
The cleanup goal [443KB PDF], a target level for drinkable water when contaminated sites are remediated, allows for perchlorate levels of 24.5 parts per billion (ppb) up from the previous level of 4–18 ppb. The new cleanup level “is not supported by the underlying science and can result in exposures that pose neurodevelopmental risks in early life,” wrote Melanie Marty, chairperson of EPA’s Children’s Health Protection Advisory Committee and chief of the Air Toxicology and Epidemiology Section in California’s Office of Environmental Health Hazard Assessment.
These risks include impaired brain development that can result in such problems [124KB PDF] as low IQ scores and attention deficits. In sufficient amounts, perchlorate inhibits the uptake of iodide, an essential component of hormones produced in the thyroid. These hormones help guide proper brain development in fetuses and infants.
The EPA goal is based on National Academy of Sciences recommendations that allow an uncertainty factor to account for one sensitive population—the fetuses of pregnant women who have untreated thyroid problems or low iodine levels. But that factor doesn’t protect infants, who could be exposed through breast milk and drinking water used in formula, the advisory committee writes.
The committee of 26 scientists wrote that because the goal follows the current EPA policy of assuming that all exposure comes from drinking water, it does not account for exposures from other sources. “This is an obvious concern given the recent widespread detection of perchlorate in lettuce and milk,” the advisers write.
As reported in February in ES&T, perchlorate appears to be ubiquitous. Water contamination was first linked to rocket fuel and ammunition, but studies have shown that perchlorate also forms naturally. Recently, it has been found in prenatal vitamins and seaweed. A small U.S. Centers for Disease Control and Prevention (CDC) study designed to test a new analytical method that detects minute amounts of the chemical found perchlorate levels in the urine of 61 CDC workers that could not be explained if the only source were drinking water.
On March 14, the Massachusetts Department of Environmental Protection released its proposed drinking-water and waste-site cleanup standards of 2 ppb. This proposal assumes that 20% of perchlorate exposure comes from water. New Jersey is considering a standard of 5 ppb and uses the same assumption, whereas California has proposed a drinking-water standard of 6 ppb and assumes that 60% comes from drinking water. EPA has not responded to the committee’s letter, but that’s not unusual, Marty adds.
