News Coverage
Milk tests find toxic chemical
Published June 21, 2004
Happy California cows may produce tasty cheese, but they also are making milk tainted with a toxic chemical found in rocket fuel, according to a study released today.
Samples of milk collected around the state by the nonprofit Environmental Working Group, or EWG, and the California Department of Food and Agriculture found perchlorate levels up to almost twice the level considered safe for consumption, the nonprofit reported.
Samples in the study included milk selected from silos by Food and Agriculture workers, including some in the department's San Joaquin County branch office. The three samples collected by the branch office showed detectable levels of perchlorate, including one sample that nearly hit the public-health goal established by the state Office of Environmental Health Hazard Assessment.
Perchlorate is the primary explosive ingredient in rocket fuel. Careless disposal of the human-made chemical has poisoned groundwater and rivers around the country.
Studies have shown ingesting significant levels of perchlorate can impair the thyroid gland and disrupt production of hormones that regulate metabolism and growth. In fetuses and young children, perchlorate can cause delayed development and lower intelligence.
EWG researchers assembled the report using data from two sources: their own studies of milk purchased from Southern California stores, and the previously unreleased Food and Agriculture Department data. The study included several brands and types of milk, including organic milk.
The data prove more aggressive standards are needed to reduce perchlorate exposure, especially in children, representatives of the environmental group said.
The California public-health goal-- an unenforceable guideline established earlier this year -- sets a goal of having perchlorate levels in drinking water at or below 6 parts per billion. That's roughly equivalent to 4 teaspoons of perchlorate in an Olympic-size swimming pool.
The highest level in a sample collected by the state agency's San Joaquin County branch was 5.6 ppb. A milk sample from the Sacramento County branch had the highest overall perchlorate level, 10.6 ppb.
The environmental group argues nearly all the milk samples included in the study would exceed the drinking-water limits proposed by the U.S. Environmental Protection Agency. However, those federal limits are based on several factors, including an individual's body weight.
EPA officials said Monday that it's difficult to say whether the milk sampled in the study would exceed any proposed federal guidelines for safe drinking water, which are under review by the National Academies of Science. It's also unclear whether drinking-water guidelines should apply to milk, EPA scientists said.
Researchers with the environmental group, who have done similar studies on perchlorate in crops, said their study wasn't meant to cause alarm over milk supplies.
"We're not trying to cause a food scare and drive people away from foods like milk that are healthy. However, those who are responsible for setting regulations need to know it's there," said Bill Walker, a vice president for the group.
Food and Agriculture Department spokesman Steve Lyle said his agency's data, collected starting in April, was not meant to serve as a public-health study. Rather, it was used to test new technology that measures perchlorate, he said.
"This was in no way a public-health study, and it is inconclusive data," he said.
More studies are needed to determine whether milk poses a health concern, Lyle said.
The perchlorate found in milk may have come from feed. Alfalfa readily accumulates perchlorate if it is irrigated with tainted water, studies have shown.
Michael Marsh, CEO of the Modesto-based trade group Western United Dairymen, said no data indicate milk is unhealthy.
He said the dairy operators are very concerned about food-safety issues and are eager to address any possible problems with chemicals getting into milk.
"I know for a fact that when I get home and my boy wants a glass of milk, he's going to get it. Milk, of course, is safe to drink. It's probably riskier for you not to drink it, given osteoporosis and other things that milk can help prevent," Marsh said.
Bruce Macler, a drinking-water toxicologist for the U.S. Environmental Protection Agency, said he's also comfortable with serving his children a cold glass of milk.
vMacler said he's "very confident" that milk with 10 ppb of perchlorate isn't a large public-health problem."Data I've seen reaches 100 to 200 (ppb) before you see people's thyroids really affected," he said.
While admitting he had not yet seen a copy of the Environmental Working Group report, Macler said previous reports from the group haven't "always been 100 percent accurate, and their science isn't always the best."
Officials with the environmental group defended their report and said that, using the EPA's own data, they found that half of all children ages 1 to 5 would exceed the EPA's own provisional safe daily dose just by drinking milk.
A third of those children would get twice that dose, according to the group.