News Coverage
Environmental group finds four tainted lettuce samples
Published April 30, 2003
The Cold War is long over, but a remnant of it continues to haunt those down river from manufacturing plants near Las Vegas that produced rocket fuel for the military dating back to the 1950s.
In a newly released study, the Environmental Working Group has warned that lettuce irrigated with Colorado River water is contaminated with perchlorate. The highly soluble salt is believed to have been leaching for years into groundwater that reaches the Colorado River at Lake Mead.
Ammonium perchlorate is a rocket fuel ingredient that was produced for more than 40 years at two plants in the Las Vegas Valley, Kerr-McGee Chemical Corp., and American Pacific Corp. (PEPCON), mainly for the military.
There has been concern over the years that the contaminant might be a health issue for those who rely on the Colorado River for their drinking water. The Colorado supplies water to 20 million people in the West.
Now, according to EWG, salads also might be suspect.
The group said that four of 22 lettuce samples it sent for independent analysis contained levels of perchlorate registering at four times the federal standard for the chemical in drinking water. The samples were gathered from grocery stores in northern California in January and February.
While the precise origin of the tested lettuce is unknown, it likely came from the desert Southwest, since Yuma and Imperial counties provide nearly all the nation's winter supply of the crop.
The EWG report is raising a number of questions and a call for sound science.
"This was a very small number of samples," said Hank Giclas, vice president of science and technology for Western Growers Association. "We're taking this seriously but encourage people to continue to eat fresh fruits and vegetables."
Giclas also stressed that perchlorate contamination is not confined to those down river from Las Vegas. "At least 22 states have detectable levels," he said, speculating that the EWG report may be an effort to encourage federal and state officials to move more quickly to contain leaks of the contaminant and clean it up.
Others maintain that perchlorate is a water-quality issue, not an agriculture one.
However, levels in the Colorado River are "well within health-based guidance levels," said Patrick Gibbons, spokesman for the Arizona Department of Environmental Quality, which did a study in 1999 of the river and Central Arizona Project canals. The study found the level of the chemical ranged from nondetectable to 9 parts per billion. The state allows up to 14 parts per billion while federal limits range from 4 to 18 parts per billion in water.
"The water here does not have a high concentration. It does warrant more study, but there is nothing to warrant saying that lettuce is unsafe. It would be unfortunate if this scares people into not eating fresh produce," Gibbons said.
"We need good science to tell us if we have a problem," said Joe Sigg, legislative liaison for the Arizona Farm Bureau. "We know it's in the water and we know where it came from. The question is in what concentration does it cause harm."
Trying to supply that answer is Charles Sanchez, an agricultural researcher at the University of Arizona Yuma Valley Experiment Farm who has been conducting his own study. He said he expects results back from the laboratory in about a month on samples he took from Yuma-area lettuce fields over the winter.