Posted by Sadie from ? (160.129.27.22) on Tuesday, April 29, 2003 at 11:19AM :
Monday, April 28, 2003
San Francisco Chronicle
Advocacy Group Finds Contaminant in Lettuce
Officials question whether chemical poses health risk
by Carl T. Hall
Potentially high levels of a toxic chemical in rocket fuel have been detected in winter lettuce purchased in Northern California supermarkets, an environmental group claims in a report being released today.
Laboratory studies commissioned by the Environmental Working Group in Oakland found the chemical perchlorate, a hormone disrupter, in four of 22 samples of lettuce traced to growers in Southern California or Arizona.
A typical serving of the contaminated lettuce would contain four times the level of perchlorate considered safe in drinking water by the U.S. Environmental Protection Agency, the study concluded. But the standards are under review, and health officials said it's unclear whether perchlorate in produce poses any significant health risk.
At high doses, perchlorate can disrupt activity of the thyroid gland, which in a pregnant woman could upset delicate hormone levels crucial for normal development of the fetus. Exposure in very young children also could pose a problem, theoretically producing deficits in brain function and motor skills.
But it's unclear how much perchlorate might be contained in salad greens or other vegetables, even those irrigated with contaminated water. Nor is it clear how much perchlorate in the diet actually would be dangerous.
Perchlorate is the explosive ingredient in rocket fuel. It is a well-known groundwater contaminant throughout the Southwest and the subject of thousands of lawsuits, but has not been deemed a significant problem in food.
COLORADO RIVER WATER
Most of the lettuce sold in the United States from November to March comes from Imperial County in California and Yuma County in Arizona. Growers in that area irrigate crops with water from the Colorado River, long suspected of being contaminated by underground plumes of perchlorate from industrial and military sites.
Conceding its study was small, the Oakland group called for the federal government to conduct a definitive study of perchlorate in the food supply, require a cleanup of military sites and tighten standards to limit potential exposure through drinking water as well as irrigation systems.
The California Office of Environmental Health Hazard Assessment, part of the state Environmental Protection Agency, already has begun working to develop perchlorate safety standards for drinking water. The federal EPA has submitted a draft health-risk assessment of perchlorate for independent scientific review.
Officials suspect contaminated drinking water, not food, poses the greatest potential danger. The environmental group said its new study, "Suspect Salads, " is the first to look systematically for perchlorate on supermarket produce shelves.
Other irrigated crops besides lettuce could pose similar dangers, said Bill Walker, a vice president of the Environmental Working Group. He said winter lettuce was studied first partly because of suspicions that contaminated irrigation water would be highly concentrated in lettuce leaves.
CAUTION ADVISED
"Pregnant women right now should be very cautious about winter lettuce," Walker said, although he added that lettuce on store shelves from April to October comes from growing regions that are not likely to pose a problem.
But regulators emphasized the health benefits of eating lots of fresh produce.
"There's not a whole lot of research out there on perchlorate in food," said James Waddell, chief of the food and drug branch of the state Department of Health Services. "We don't have a good sense for what levels are of concern.
This new data certainly is something we are going to take a look at."
RECOMMENDATIONS REMAIN
He said the department "continues to recommend men, women and children consume a balanced diet rich in fruits and vegetables. Until the science shakes out on this, it would be premature to ask people to reduce or restrict consumption of any of these products."
Edith Garrett, president of the International Fresh-Cut Produce Association, an industry group based in Alexandria, Va., said the new findings should be considered suspect.
"This was based on a very small sample," she said. "I'm not sure if anybody can extrapolate any suggestions at all from this small of a sample, and there's no other data similar to this."
Garrett said growers want more definitive answers from government agencies, both at the federal and state level. Until more is known, she said, pregnant women shouldn't think twice about a diet rich in leafy greens.
©2003 San Francisco Chronicle
-- Sadie
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