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Issues: Growing and ProductionPMA Overview: PerchloratePerchlorate (ClO4) is a both naturally occurring and synthetic compound. Most of the perchlorate manufactured in the United States is used as an ingredient of solid rocket propellant. Perchlorate has also been used as a medicine to treat hyper-thyroid conditions. Perchlorate-containing wastes have been discovered in at least 22 states in soil and water (ground and surface water). This is a nationwide issue of water quality that requires an overarching solution based on sound science. In early 2003, an activist group alleged that perchlorate in lettuce irrigation sources may have been absorbed in the sampled lettuce (the samples likely came from the 2002-2003 crop from the Imperial Valley of California and Yuma, Arizona). The report acknowledged that the sample size was too small to draw any conclusions, and the U.S. Food & Drug Administration (FDA) concurred with that conclusion. Allegations about perchlorate in lettuce and other leafy vegetables initially focused this issue on those crops, and other food crops may be included in the future. However this is a nationwide issue of water quality and ultimately requires an overarching solution based on sound science that involves many entities, including the U.S. and state governments. Effects of PerchlorateAt high doses, perchlorate can interfere with iodide uptake into the body’s thyroid gland, disrupting its functions, according to the FDA. At low levels, this effect may not pose a significant health risk to adults with healthy, functioning thyroid glands. Science concerning sensitive sub-populations is unclear. Perchlorate is not a carcinogen, does not accumulate in the body, and is excreted within hours. In adults, the thyroid helps to regulate metabolism. In children, the thyroid plays a major role in proper development in addition to metabolism. Impairment of thyroid function in expectant mothers may affect the fetus and newborn and result in effects including delayed development and decreased learning capability. Chronic lowering of thyroid hormones due to high perchlorate exposure may also result in thyroid gland tumors. Consumption of ProduceNo public health authority has asked consumers to change their eating habits based on perchlorate. Consumers should eat at least five servings of fruits and vegetables a day. If this were a public health problem, industry and public health authorities would take immediate action. Standards Currently, there are no U.S. federal regulations or standards for perchlorate. Government and independent organizations are conducting and reviewing studies on the potential health impact of perchlorate and are working to determine what levels are considered safe. The U.S. Environmental Protection Agency says adequate data do not exist to warrant classifying perchlorate as a contaminant in drinking water. FDA said: “At this time, further studies are needed to determine the health risk associated with exposure to perchlorate from foods. If an elevated health risk is determined, FDA will seek ways to reduce dietary exposure to perchlorate.” The U.S. National Academy of Sciences also conducted an independent review in 2004 on perchlorate. More on the NAS study is provided below (see Preliminary Results). TestingFDA has developed a rapid, sensitive, and specific ion chromatography-tandem mass spectrometry (IC-MS/MS) method for determining perchlorate in selected foods, such as lettuce, milk, and bottled water. The smallest amount of perchlorate that this method can detect, or the limit of detection (LOD), is 0.30 ppb for fruits, fruit juices, and vegetables; 1.00 ppb for milk, grain products, fish, and shrimp; and 0.20 ppb for bottled water.
For FY05, FDA expanded the exploratory survey. Besides collecting additional samples of tomatoes, carrots, spinach, and cantaloupe, FDA collected samples of other high water content foods, including fruits and fruit juices such as apples, oranges, and grapes; vegetables such as cucumbers, green beans, and greens; and seafood such as aquaculture fish and shrimp. The complete set of perchlorate data obtained from the FY04 and FY05 exploratory surveys is available on FDA's Web site. Industry ActionAlthough this is not an acute public health problem, recent publicity has raised questions, many of which cannot be answered definitively until thorough scientific studies are complete. The fresh produce industry is actively working on this issue within the research and regulatory communities. The fruit and vegetable industry has formed a comprehensive coalition to work on the issues associated with the allegations leveled by the activists and the perceptions created by the media. We are working in a variety of strategic areas including policy development, regulatory action, public relations, and legal strategies. The industry has also commissioned the testing and analysis of a wide variety of individual fruits and vegetables with a combination of both private and public funds. A few early results are available (see below), but it is critical to note that sufficient time is needed to allow for the broad sampling and analysis needed to develop risk assessments for fruits and vegetables. The produce industry is working with USDA and the FDA as well as with state health organizations to collect and interpret these samples and then to present them in a manner that minimizes any potential for misinterpretation. Preliminary ResultsThe results of tests to date range from no detections to only trace amounts in the edible parts of crops, which is very encouraging. The results will be further analyzed against accepted exposure models that incorporate reference doses for fresh foods, which are being developed but currently do not exist. When indexed against conservative public health goals and assessed by respected toxicologists, preliminary results show that there is no evidence to suggest that perchlorate in produce presents any harm. It is expected that the full results will further reassure buyers and the public of the safety of the food supply, particularly fresh produce. The government, scientists, and water/food industries (including the produce industry) will continue to learn as new research and government reports on acceptable levels of perchlorate in food and water are released. They will act on credible scientific information as warranted. On January 11, 2005, the National Academy of Sciences' National Research Council released a report on perchlorate, “Health Implications of Perchlorate Ingestion,” a long-awaited tool policy makers will use to develop science-based standards to ensure public health. The report is based on an exhaustive review of research on the health effects of perchlorate. On August 11, 2005, an independent scientific panel decided against adding perchlorate to the Proposition 65 list of chemicals known to the State of California to cause birth defects or other reproductive harm. The state's Developmental and Reproductive Toxicant (DART) Identification Committee, a panel of independent scientists administered by the California Environmental Protection Agency's Office of Environmental Health Hazard Assessment (OEHHA), concluded that available scientific information on perchlorate was not sufficient for placing the substance on the Proposition 65 list. ConclusionThis is an issue of paramount importance for the entire industry, and everyone needs to understand and be informed. Sound science must prevail, and that may take some time. As the industry waits for those results, it is important to remember that this is not an immediate public health threat, and no one is advised to stop eating any fresh fruit or vegetable. PMA Member Perchlorate Briefings and Resources
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