US lettuce contains rocket fuel pollutant

EDIE, Staff Writer
Published May 1, 2003

A study of a sample of lettuces on sale in supermarkets in the US has found that 18% contain perchlorate, on average having four times more of the pollutant than the level considered safe in drinking water.

The analysis has been carried out by researchers at the Institute of Environmental and Human Health at Texas Tech University, commissioned by the non-profit organisation, the Environmental Working Group.

According to EWG, 70% of the US's winter lettuce is grown in the area irrigated by water from the Colorado River, which is polluted by perchlorate. The chemical is the explosive component of rocket and missile fuel - although it also occurs naturally. It also contaminates more than 500 drinking water sources in 20 states, serving over 20 million people, says the group.

The pollutant can affect the thyroid gland's ability to make essential hormones, which can have can have an impact on the development of foetuses and very young children. The US Environmental Protection Agency currently recommends that one part per billion is a safe dose in drinking water.

The study's findings show that perchlorate is a national concern, says Renee Sharp, a senior analyst at EWG and co-author of the report. "To protect people from perchlorate not just in water but food, safety standards will have to be much tougher than what's currently proposed."

EWG has made a number of recommendations, including that the Colorado River should be cleaned up; that the Food and Drug Administration and the US Department of Agriculture should conduct a study of perchlorate contamination in food; and that the national safety standard for perchlorate in drinking water should be no higher than 0.1 ppb.

The EPA is currently awaiting the outcome of a study by the National Academy of Science into perchlorate, and was unable to comment to edie.