Exploratory Survey Data on Perchlorate in Food 2004-2005 (2024)

Perchlorate

Table 1: Perchlorate Values in Lettuce Samples
Table 2: Perchlorate Values in Bottled Water Samples
Table 3: Perchlorate Values in Milk Samples
Table 4: Perchlorate Values in Tomato Samples
Table 5: Perchlorate Values in Carrot Samples
Table 6: Perchlorate Values in Spinach Samples
Table 7: Perchlorate Values in Melon Samples
Table 8: Perchlorate Values in Fruit Samples
Table 9: Perchlorate Values in Fruit Juice Samples
Table 10: Perchlorate Values in Vegetable Samples
Table 11: Perchlorate Values in Grain Samples
Table 12: Perchlorate Values in Fish and Seafood Samples

Background

Perchlorate is a naturally occurring and manmade chemical. Naturally occurring perchlorate, for example, is found in arid states (e.g., Texas), as well as in nitrate fertilizer deposits in Chile and potash found in United States and Canada. Most of the perchlorate manufactured in the United States is used as the primary ingredient of solid rocket propellant. Perchlorate is also used in pyrotechnics, such as fireworks, gun powder, explosives, and highway flares. In addition, perchlorate is used in a wide variety of industrial processes, including tanning and leather finishing, rubber manufacture, paint and enamel production, and additives in lubricating oils.

In recent years there has been increasing interest in perchlorate levels in soil, ground water, drinking water, and irrigation water around the country and what health effects these levels may have. Human exposure to sufficient doses of perchlorate can interfere with iodide uptake into the thyroid gland, disrupting its functions and potentially leading to a reduction in the production of thyroid hormones.

In order to work toward development of an assessment of the potential risk of perchlorate, FDA is conducting exploratory surveys to better understand the occurrence and levels of perchlorate in a variety of foods from various locations. The levels of perchlorate found in the foods analyzed will also be used to better understand perchlorate exposure from food and to support action, if warranted, to protect the public health.

For determining perchlorate levels in food, a rapid, sensitive, and specific ion chromatography-tandem mass spectrometry (IC-MS/MS) method, developed by FDA, with limits of quantitation of 0.5 part per billion (ppb) for bottled water; 1.0 ppb for produce; and 3.0 ppb for milk, grain products, and seafood was used. This method, entitled "Determination of Perchlorate Anion in Foods by Ion Chromatography-Tandem Mass Spectrometry," has been published in the September 15, 2004 issue of Analytical Chemistry (Analytical Chemistry, 2004, 76, 5518-5522) and is posted on CFSAN's internet website.

2004/2005 Exploratory Surveys

The data

The data presented below in Tables 1-12 are results from exploratory surveys of individual food products conducted by FDA during Fiscal Years (FY) 2004 and 2005 (a fiscal year covers the period from October 1 in a year to September 30 in the following year, e.g., FY 2004 is from October 1, 2003 to September 30, 2004).

During FY04, FDA conducted an initial exploratory survey in which FDA collected samples of domestic origin of seven food products (bottled water, milk, lettuce, tomatoes, carrots, spinach, and cantaloupe). The overall goal of the sampling plan (convenience samples, not necessarily representative of the U.S. food supply) was to gather initial information on occurrence of perchlorate in foods from various locations with a high likelihood of perchlorate contamination. The produce samples (lettuce, tomatoes, carrots, spinach, and cantaloupe) were collected particularly from regions (i.e., Southern California and Arizona) where water sources are known to be contaminated with perchlorate based on a study report of detecting perchlorate in winter lettuce grown in Southern California or Arizona (Environmental Working Group. Suspect Salads: Toxic rocket fuel found in samples of winter lettuce. 2003.) and thus, the perchlorate levels are likely to be biased high. Bottled water and milk samples were collected from throughout the country. Produce samples (lettuce, tomatoes, carrots, spinach, and cantaloupe) were selected for the survey based on their high water content, relatively high consumption, and early indications of perchlorate uptake by plants, when irrigated with perchlorate-containing water or when plants are grown in soil that naturally contains perchlorate or that has been previously exposed to perchlorate-containing water or fertilizer. Additional information on sample collection and perchlorate analysis by FDA field offices during FY04 is provided in a document entitled " FDA Collection and Analysis of Food for Perchlorate - High Priority - DFP # 04-11" posted on CFSAN's internet website.

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. In addition, grain products such as wheat flour, cornmeal, and rice were sampled as a follow up to a Texas Tech University study report finding perchlorate in wheat heads (Jackson et al., Perchlorate Accumulation in Forage and Edible Vegetation. 2005, 53:369-373. J. Agric. Food Chem.). The FY05 samples collected by FDA consisted of domestic products grown in a broader range of locations within the United States (i.e., Florida, Georgia, Idaho, Indiana, Illinois, Iowa, Kansas, Louisiana, Maine, Mississippi, Missouri, Montana, Nebraska, New Jersey, New Mexico, North Carolina, Ohio, Oregon, Pennsylvania, South Carolina, Texas, Washington) to determine if perchlorate occurs in foods from wider regions of the United States, and not only from regions where water sources are known to be contaminated with perchlorate. In FY05, FDA also collected and analyzed a limited number of imported products commonly entering the U.S. market (e.g., produce from Mexico, grapes from Chile, aquaculture salmon from Canada, shrimp from Southeast Asia) that were available for sampling during FY05. However, food samples (domestic and imported) collected in FY05 are also convenience samples and are not necessarily representative of the U.S. food supply. Additional information on sample collection and perchlorate analysis by FDA field offices during FY05 is provided in a document entitled " FDA Collection and Analysis of Food for Perchlorate - High Priority - DFP # 05-09" posted on CFSAN's internet website.

Domestic produce samples were collected at the grower or packing shed, while fruit juice and import samples were collected at retail establishments. For sample analysis, only the edible portion of fruit, vegetable, and seafood samples were used to determine perchlorate levels. In addition, outermost leaves of each lettuce head were removed, similar to the actions typically taken by a consumer prior to consumption, while the entire bunch of spinach was used to determine perchlorate levels.

Limitations of the data

The FY04/05 exploratory survey data consist of 27 types of foods and beverages(1), representing only about 32 and 42 percent of the total diet for the U.S. population, ages 2 years and older and for children, 2-5 years, respectively. In addition, the data cover a limited number of samples of these foods and a limited number of brands. Also, the data do not fully address the variation from one unit of a food product to another unit of the same product, or from one production lot or production area of a food product to another lot. Further, the choice of food products for testing in this exploratory survey should not be taken as an indicator of food product choices by consumers or of food product recommendations by FDA.

To help address these limitations, FDA is continuing to test additional food types for perchlorate. In FY05 and FY06, FDA tested for perchlorate levels in samples of baby and adults foods, respectively, collected under FDA's Total Diet Study (TDS) survey. FDA is preparing a perchlorate exposure assessment based on FDA's FY05/06 TDS data which is expected to be released in the fall of 2007. TDS is FDA's ongoing market basket survey in which more than 280 core foods (TDS foods) in the U.S. food supply are collected and analyzed to determine levels of various contaminants and nutrients in those foods.

What Consumers Should Understand

Consumers should not view the perchlorate levels as an indicator of perchlorate exposure, or as the "risk" of eating certain foods. First, perchlorate levels alone do not equate to perchlorate exposure; calculating exposure requires consideration of both perchlorate levels, and the amounts of food that consumers eat. Second, estimates of perchlorate exposure take into account not single food items, but the wide variety of foods found in a range of diets. Third, the scope of the data is too limited to properly consider potential sources of variation in measured perchlorate levels, such as variability between different units or lots of food. Fourth, the impacts of perchlorate exposure will vary depending upon an individual's iodine sufficiency. Thus, the data were not generated to be representative of the perchlorate levels in the U.S. food supply but are only exploratory in nature.

Until more is known about the health effects of perchlorate and its occurrence in foods, FDA recommends a healthy eating plan, consistent with the Dietary Guidelines for Americans, that emphasizes fruits, vegetables, whole grains, and fat-free or low-fat milk and milk products; includes lean meats, poultry, fish, beans, eggs, and nuts; and is low in saturated fats, trans fats, cholesterol, salt (sodium) and added sugars. Additionally, adequate intake of iodine has previously been recognized as important for healthy thyroid function.

Exposure Estimates

FDA's CFSAN estimated human exposure to perchlorate through consumption of 27 foods and beverages for which CFSAN has collected data on perchlorate levels (See "Preliminary Estimation of Perchlorate Dietary Exposure Based on FDA 2004/2005 Exploratory Data"). Data sources for the 27 foods and beverages are from FDA's FY04/05 exploratory surveys that are presented in this document.

Notes:
(1) ND = not detected
(2) The estimated limit of quantitation (LOQ) is 1.00 ppb for lettuce.
(3) The estimated limit of detection (LOD) is 0.30 ppb for lettuce.
(4) * =Estimate, Below LOQ and above LOD.

Notes:
(1) ND = not detected
(2) The estimated limit of quantitation (LOQ) is 0.50 ppb for water.
(3) The estimated limit of detection (LOD) is 0.20 ppb for water.
(4) * =Estimate, Below LOQ and above LOD.

Notes:
(1) ND = not detected
(2) The estimated limit of quantitation (LOQ) is 3.00 ppb for milk.
(3) The estimated limit of detection (LOD) is 1.00 ppb for milk.
(4) * =Estimate, Below LOQ and above LOD.

Notes:
(1) ND = not detected
(2) The estimated limit of quantitation (LOQ) is 1.00 ppb for tomatoes.
(3) The estimated limit of detection (LOD) is 0.30 ppb for tomatoes.
(4) * =Estimate, Below LOQ and above LOD.

(1) ND = not detected
(2) The estimated limit of quantitation (LOQ) is 1.00 ppb for carrots
(3) The estimated limit of detection (LOD) is 0.30 ppb for carrots.
(4) * =Estimate, Below LOQ and above LOD.

Notes:
(1) ND = not detected
(2) The estimated limit of quantitation (LOQ) is 1.00 ppb for spinach.
(3) The estimated limit of detection (LOD) is 0.30 ppb for spinach.
(4) * =Estimate, Below LOQ and above LOD./p>

Notes:
(1) ND = not detected
(2) The estimated limit of quantitation (LOQ) is 1.00 ppb for melons
(3) The estimated limit of detection (LOD) is 0.30 ppb for melons
(4) ** =Estimate, Below LOQ and above LOD.

Notes:
(1) ND = not detected
(2) The estimated limit of quantitation (LOQ) is 1.00 ppb for fruits.
(3) The estimated limit of detection (LOD) is 0.30 ppb for fruits.
(4) * =Estimate, Below LOQ and above LOD.

Notes:
(1) ND = not detected
(2) The estimated limit of quantitation (LOQ) is 1.00 ppb for fruit juices.
(3) The estimated limit of detection (LOD) is 0.30 ppb for fruit juices.
(4) * =Estimate, Below LOQ and above LOD.

Notes:
(1) ND = not detected
(2) The estimated limit of quantitation (LOQ) is 1.00 ppb for vegetables.
(3) The estimated limit of detection (LOD) is 0.30 ppb for vegetables.
(4) * =Estimate, Below LOQ and above LOD.

Notes:
(1) ND = not detected
(2) The estimated limit of quantitation (LOQ) is 3.00 ppb for grains.
(3) The estimated limit of detection (LOD) is 1.00 ppb for grains
(4) * =Estimate, Below LOQ and above LOD.

Notes:
(1) ND = non-quantifiable
(2) The estimated limit of quantitation (LOQ) is 3.00 ppb for fish and seafoods.
(3) The estimated limit of detection (LOD) is 1.00 ppb for fish and seafoods
(4) * =Estimate, Below LOQ and above LOD.

(1) Bottled water was not included among the 27 types of foods and beverages because only 2 out of 51 samples were found to contain perchlorate levels near the limit of quantitation (i.e., 0.5 parts per billion) and therefore was not included in estimating human exposure.