News Coverage
Group issues new warning on winter lettuce
Published April 28, 2003
LETTUCE PURCHASED in the fall and winter months may come with an unintended additive: toxic levels of a rocket fuel ingredient that has contaminated river and well water, according to a new report from the Environmental Working Group.
Every day, hundreds of pounds of the contaminant, perchlorate, enter the lower Colorado River, said Renee Sharp, an analyst with the group, which has offices in Washington, D.C., and Oakland. The contaminated water provides irrigation water for 1.4 million acres in a region growing most of the nation's winter vegetable crops.
The contaminant comes from a shuttered rocket fuel plant near Las Vegas that was once run by Kerr-McGee of Oklahoma City. The environmental group had 22 types of lettuce tested, including conventionally grown and organic. Scientists found that 18 percent of the samples contained detectable levels of perchlorate, and an average serving of these samples contained four times more of the toxic chemical than the Environmental Protection Agency deems safe in a liter of drinking water. This isn't the first study on the infiltration of the rocket fuel ingredient into produce, Sharp said.
"The data is very clear that perchlorate can be concentrated in vegetables," she said.
Perchlorate interferes with the thyroid's ability to uptake iodine. That in turn reduces the thyroid's production of hormones necessary for the healthy functioning of the central nervous system. Health officials mostly worry about pregnant women being exposed to the chemical, as it can impair fetal development, leading to lowered IQ and other neurological damage.
Alan Hirsch, a spokesman with the state's Office of Environmental Health Hazard Assessment, said the office hasn't studied the report and doesn't yet have comment on it. However, the health hazard office has reported that 80 percent of human exposure to perchlorate comes from water, and 20 percent from food. The environmental group actually thinks the exposure is 60 percent from water and 40 percent from food, and that the health hazard office changed the number due to industry pressure. Hirsch denied that, saying that the agency changed it after seeing EPA data on the presence of perchlorate in produce.
Sharp emphasized that lettuce now in stores should be free of the toxic chemical, as this time of year lettuce is grown in regions, like Monterey County, not known to have perchlorate-contaminated irrigation water.
"This isn't going to be an issue until the fall," Sharp said. "A lot of clean-up can happen by then, and we hope it will."