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faucetA Homeowner's Guide to Perchlorate
Prepared by the New Jersey Department of Environmental Protection's Division of Water Supply and Geoscience - Bureau of Safe Drinking Water and Division of Science, Research and Technology
Updated: November 2005

Q1. What is perchlorate?

A1. Perchlorate is a naturally occurring inorganic chemical compound that can also be manufactured. One source of perchlorate is found as naturally occurring deposits in Chile that are mined and used as fertilizer in the United States. Much of the perchlorate manufactured in the United States is used as the primary ingredient in solid rocket propellant. Perchlorate is also used in a wide variety of industrial processes and fireworks, matches, lubricating oils and air bags. Wastes from the manufacture and improper disposal of perchlorate-containing chemicals are increasingly being discovered in soil and water. In recent years, there has been growing interest nationwide in perchlorate levels in soil, groundwater, drinking water and irrigation water, and the potential health effects of exposure to perchlorate.

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Q2. Where has perchlorate-contaminated water been found?

A2. Perchlorate has been detected in water in more than 20 states throughout the nation. The U.S. Environmental Protection Agency (EPA), other federal agencies, states, water suppliers and industry are addressing perchlorate contamination by monitoring for perchlorate in both drinking water and source water. The extent of perchlorate contamination is not known at this time. Perchlorate has been found in some public and private water systems in New Jersey. Measures are being taken to ensure the safety of surrounding wells and water systems.

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Q3. How can perchlorate affect human health?

A3. The National Research Council of the National Academy of Sciences reviewed the health effects of ingested perchlorate and issued its conclusions in January 2005. At sufficient doses, perchlorate interferes with iodide uptake into the thyroid gland. Because iodide is an essential component of thyroid hormones, higher doses of perchlorate disrupt thyroid functions and decrease the production of thyroid hormones T3 and T4. In adults, the thyroid helps regulate metabolism. In children, the thyroid plays a major role in proper development of the central nervous system and skeleton, in addition to regulating metabolism. In expectant mothers, impairment of thyroid function may have adverse effects on the fetus and the newborn, including behavior changes, delayed development and decreased learning capability.

Short-term exposure to perchlorate is expected to have effects similar to chronic exposure because the inhibition of iodide uptake occurs within a short time. Further, perchlorate does not accumulate in the body even with constant exposure.

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Q4. Does perchlorate cause cancer?

A4. According to the National Academy of Sciences report, laboratory animals develop benign tumors only when given very high doses of either perchlorate or other chemicals that interfere with thyroid function. The National Academy of Sciences concluded that it is unlikely that perchlorate at levels usually found in the environment would cause thyroid cancer or benign tumors in humans, citing the differences in thyroid function in animals and humans.

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Q5. Is there a standard for perchlorate in drinking water?

A5. As of now, there is no drinking water standard for perchlorate, but the federal EPA finalized its human health risk assessment for perchlorate ingestion following the National Academy of Sciences review. The "Reference Dose" (RfD)1 adopted directly from the National Academy of Sciences review is based on the finding that daily ingestion of up to 0.0007 milligrams per kilogram of body weight can occur without adversely affecting the uptake of iodine into the thyroid. At this level, no effects on thyroid function are expected, and the RfD is protective for the most sensitive persons. This is equivalent to approximately 0.045 milligrams per day (or 45 micrograms) in a pregnant woman or 0.05 milligrams per day in an average-weight man. A protective drinking water concentration is based on the following assumptions: 1) adults drink two liters of tap water per day; 2) tap water consumption accounts for 20 percent of an adult's daily exposure to perchlorate; and 3) perchlorate also occurs in some foods. Based on these assumptions, a health-based drinking water concentration would be 5 parts per billion (ppb)2.

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Q6. Is perchlorate-contaminated water safe to drink or use?

A6. It is important to recognize that conservative assumptions are used to develop the RfD. Exposures at levels above the RfD will not necessarily result in adverse health effects. However, the RfD and the drinking water concentration of 5 ppb for perchlorate are intended to protect public health, particularly sensitive populations including pregnant women, children and those with health problems or compromised thyroid function.While there currently is no regulatory standard for perchlorate, the New Jersey Department of Environmental Protection (DEP) recommends that people avoid drinking water known through confirmed testing to contain more than 5 ppb of perchlorate. If you elect to use bottled water, you should consider contacting the producer to determine if sampling for perchlorate is done as discussed below. Also, avoid cooking with water containing perchlorate levels above 5 ppb because boiling the water may increase the perchlorate concentration in the food being prepared.Water contaminated with perchlorate can be used for showering, bathing and washing clothes and dishes. However, children should be closely watched during bathing to ensure they do not ingest the water.

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Q7. Who should test their drinking water for perchlorate?

A7. Although a drinking water standard for perchlorate has not yet been established, some public water systems voluntarily conduct sampling for perchlorate. Contact your water system to find out if perchlorate sampling is being performed.If you are served by a private well, the DEP recommends testing by a New Jersey certified lab if you are concerned about possible perchlorate contamination or are aware of perchlorate contamination nearby. Contact your local health department for more information about perchlorate testing or possible contamination in your area.For more information on private wells, visit the DEP's Private Well Testing Act website or the EPA's Private Well Web site at

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Q8. Where can I get my well tested?

A8. Analysis should be done by a New Jersey certified lab. The DEP's Office of Quality Assurance offers a list of New Jersey certified labs at or by calling (609) 292-3950.

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Q9. Do bottled water manufacturers test for perchlorate?

A9. Neither the U.S. Food and Drug Administration (FDA) nor the Bottled Water Program in the New Jersey Department of Health has established a standard for perchlorate in bottled water. Current regulations for bottled water do not require bottlers to test for perchlorate. The bottled water industry is aware of the potential for perchlorate contamination in source waters, and some bottlers may voluntarily test for perchlorate. Consumers should contact the producers of their favorite brands for more information.

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Q10. How is perchlorate removed from water?

A10. Currently, New Jersey has little experience with perchlorate treatment. DEP expects based on other States' experiences, the following types of treatment will be most appropriate for the treatment of perchlorate at the levels found in drinking water: ion (anion) exchange, membrane technology, and potentially whole house carbon adsorption. Additionally, point of use treatments, such as reverse osmosis and distillation, may remove perchlorate from drinking water.

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Q11. Where else has perchlorate been found?

A11. Available information indicates that perchlorate is present in the food supply, including cow's milk and lettuce. Perchlorate has also been found in breast milk. The FDA is currently conducting additional studies of perchlorate in food. For more information, visit the FDA's Web site at

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Q12. Where can I get more information?

A12. The EPA Web page,, can provide the most recent perchlorate information. You can also contact the DEP's Bureau of Safe Drinking Water at or (609) 292-5550.

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1"Reference Dose" is defined as an estimate of a daily oral exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime.

2 The New Jersey Drinking Water Quality Institute has made a recommendation of 5 ppb as a MCL to the DEP. The DEP anticipates proposing a regulation reflecting the recommendation prior to January 31, 2006. In the interim, the DEP recommends that anyone with a New Jersey certified lab result for perchlorate that exceeds 5 ppb take remedial measures.

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