19 September 2003
LUBBOCK, TX, Sept. 19 - A toxic component of rocket fuel has been found in supermarket milk at levels exceeding the federal government's currently recommended safe dose for drinking water, according to a peer-reviewed scientific study published today.
A team of five researchers from the Institute of Environmental and Human Health at Texas Tech University report in the journal Environmental Science and Technology that perchlorate was "unambiguously detected" in seven of seven cow's milk samples from Lubbock grocery stores.
Perchlorate levels in the milk ranged from 1.7 to 6.4 parts per billion - all higher than the U.S. Environmental Protection Agency's most recent proposed safety standard of 1 ppb. Enforceable federal standards are not expected for at least five years, but the State of California has set 4 ppb of perchlorate as the "action level" at which a public water supply should be shut down.
Perchlorate, the explosive main ingredient of solid rocket and missile fuel, can disrupt 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.
Perchlorate, most of it leaking from military bases or defense plants, contaminates more than 500 drinking water supplies in at least 20 states, serving well over 20 million people. Among major perchlorate-polluted sources is the Colorado River, which is used to irrigate 1.4 million acres of cropland in California and Arizona. Earlier this year, a study for the Environmental Working Group, conducted by the same team from Texas Tech, reported that about 1 in 5 samples tested of winter lettuce irrigated by the Colorado had perchlorate levels averaging four times the EPA's draft safety standard. ( http://www.ewg.org/suspectsalads.pdf .)
"These troubling results are the first indication that perchlorate is not only contaminating drinking water and irrigation water, but that livestock can pass it on to humans," said EWG Senior Analyst Renee Sharp. "How much more evidence do we need before the government takes action to protect our water, our food and our selves from this toxic chemical?"
The milk samples represented six different brands, four packaged locally at the same plant and two at separate plants outside Texas. Researchers also found perchlorate in one sample of evaporated cow's milk (1 ppb) and one sample of human breast milk (about 4 ppb), but none was found in a sample of reconstituted powdered milk.
Levels of perchlorate in Lubbock-area drinking water range from below the limit of detection to 4 ppb, with the average about 2.5 ppb. Previous research by the Texas Tech scientists has shown that feed crops such as alfalfa can take up and concentrate perchlorate to high levels. The researchers have also documented perchlorate contamination of field-grown wheat, blackberries, chinaberries, mulberries and in lab-grown lettuce, soybeans, strawberries and cucumbers.
"The significant occurrence of perchlorate in all milk samples analyzed at levels that are comparable or even greater than the current California action level for the concentration of perchlorate in drinking water came as a considerable surprise to us," wrote the authors. "Based on this limited study, it is not clear how widespread perchlorate contamination of milk may be, but clearly such a study is warranted."
EWG renews its call for the U.S. Food and Drug Administration and Department of Agriculture to fast-track a definitive study of perchlorate contamination in the U.S. food supply, and make all results public. All future drinking water standards, such as those currently under consideration by California, must adequately reflect the potential for exposure through food. Farmers and ranchers must be fully compensated for lost profits and property values.
Lenny Siegel, Director, Center for Public Environmental Oversight