Scientists on Tuesday reported that perchlorate, a toxic component of rocket fuel, was contaminating virtually all samples of women's breast milk and its levels were found to be, on average, five times greater than in cow's milk.
The contaminant, which originates mostly at defense industry plants, previously had been detected in various food and water supplies around the country. But the study by Texas Tech University's Institute of Environmental and Human Health was the first to investigate breast milk.
The findings concern health experts because infants and fetuses are the most vulnerable to the thyroid-impairing effects of the chemical.
Perchlorate contamination -- An article in Wednesday's Section A about chemical contamination of breast milk said levels of perchlorate, a toxic component of rocket fuel, are particularly high in the lower Colorado River. The levels used to be high but are now low because a remediation system has been cleaning contaminated ground water at a now-defunct Kerr-McGee chemical plant.
Breast milk from 36 women in 18 states, including California, was sampled, and all contained traces of perchlorate.
Perchlorate blocks the nutrient iodide and inhibits thyroid hormones, which are necessary for brain development and cellular growth of a fetus or infant. A baby with impaired thyroid development may have neurological defects that result in lower IQ or learning disabilities.
The researchers recommended that pregnant and nursing women block the effects of perchlorate by taking iodine supplements as a precaution.
At the levels they found in breast milk, the scientists reported that 1-month-old infants would take in enough perchlorate to exceed a safe level, called a reference dose, that was established last month by a panel of the National Academy of Sciences.
"It is obvious that the NAS safe dose
The findings come as the U.S. Environmental Protection Agency is developing an enforceable limit on the amount of perchlorate in drinking water based on the recommendations of the National Academy of Sciences panel. Currently there is no national standard.
"This is not just another study," said Renee Sharp, a senior analyst at the Environmental Working Group, which advocated a strict national standard. "It ends the questions about whether women are passing along perchlorate to their kids through breast milk, and the sky-high levels the scientists found put more than half the kids over the safe levels the NAS now recommends."
Environmentalists have urged the EPA to set its standard based on the body weight and perchlorate intake of an infant rather than an adult. Toxicologists said that would probably mean a standard of a few parts per billion. Pentagon officials have said that would shut down many water systems across the country and cost the military and its contractors billions of dollars in cleanup costs. They have instead lobbied for a standard of about 200 parts per billion based on thyroid studies of adults.
- Officials Blast EPA on Perchlorate Standards Mar 16, 2006
- Too Much Perchlorate in Milk, Report Says Jun 22, 2004
- The Poison of Ignorance Apr 29, 2003
