OAKLAND, June 22 — Milk from cows raised in some parts of California may expose infants and children to more of a toxic rocket fuel chemical than is considered safe by the U.S. Environmental Protection Agency (EPA) and the State of Massachusetts, according to unreleased tests by state agriculture officials and independent laboratory tests commissioned by Environmental Working Group (EWG).
In the first study to look for perchlorate in California supermarket milk, EWG found the rocket fuel chemical in almost every sample tested - 31 out of 32 samples purchased from grocery stores in Los Angeles and Orange counties. The average level of perchlorate in the samples was 1.3 parts per billion (ppb) — just above the EPA's currently recommended safe dose of 1 ppb.
Through a state Public Records Act request, EWG also obtained results of tests for perchlorate in milk by the California Department of Food and Agriculture (CDFA), which the agency has not made public or provided to state health officials. CDFA's tests found perchlorate in all 34 samples of milk collected from unspecified sources in Alameda, Sacramento, and San Joaquin counties. The average level of perchlorate in the samples was 5.8 ppb, or just below the state's recently set Public Health Goal of 6 ppb.
A computer-assisted analysis of federal dietary data shows that by drinking milk contaminated with the levels of perchlorate found in the two studies, half of all children 1 to 5 would exceed EPA's provisional daily safe dose just by drinking milk, and more than a third would get twice that dose. One-third of children 6 to 11 would get a larger dose than EPA says is safe, with one-fifth consuming twice as much.
Perchlorate, the explosive component of solid rocket fuel, can affect the thyroid gland's ability to make essential hormones. For fetuses, infants and children, disruptions in thyroid hormone levels can cause lowered IQ, mental retardation, loss of hearing and speech, and motor skill deficits.
Currently there are no enforceable perchlorate safety standards at the state or federal level. The state's Public Health Goal of 6 ppb will be used to set a final drinking water standard, expected early next year.
"Our findings are not a call for California mothers to stop drinking milk or stop giving it to their children," said Bill Walker, EWG Vice President/West Coast. "They do show that the state must set a drinking water standard that fully protects public health. Mothers should not be forced to wonder if milk is affecting their child's growth and development."
Perchlorate contaminates more than 350 drinking water sources in California alone. Nationally, perchlorate contamination of drinking water has been confirmed by testing in 22 states. Among contaminated sources is the Colorado River, which not only provides drinking water for Los Angeles, Phoenix, Las Vegas and other cities, but also irrigates 1.4 million acres of farmland in California and Arizona. Many crop and feed plants, including lettuce, cucumbers, tomatoes and alfalfa, concentrate perchlorate in their tissues when grown with contaminated water. The perchlorate ingested by cows in their water and feed is passed along in milk.
