Safe Drinking Water Act
Perchlorate occurs naturally in arid states in the Southwest United States, in nitrate fertilizer deposits in Chile, and in potash ore in the United States and Canada. It also forms naturally in the atmosphere. Perchlorate can be manufactured and used as an industrial chemical and can be found in rocket propellant, explosives, fireworks and road flares. It has also been found in some public drinking water systems and in food.
Above certain exposure levels, perchlorate can interfere with the normal functioning of the thyroid gland by inhibiting the transport of iodide into the thyroid, resulting in a deficiency of iodide in the thyroid. Perchlorate inhibits (or blocks) iodide transport into the thyroid by chemically competing with iodide. The transfer of iodide from the blood into the thyroid is an essential step in the synthesis of thyroid hormones. Thyroid hormones play an important role in the regulation of metabolic processes throughout the body and are also critical to developing fetuses and infants, especially for brain development. Because the developing fetus depends on an adequate supply of maternal thyroid hormones for its central nervous system development during the first and second trimester of pregnancy, iodide uptake inhibition from perchlorate exposure has been identified as a concern in connection with increasing risk of neurodevelopmental impairment in fetuses of pregnant women with low dietary iodine. Poor iodide uptake and subsequent impairment of the thyroid function in pregnant and lactating women have been linked to delayed development and decreased learning capability in their infants and children. There is scientific evidence to support that perchlorate can reduce iodide uptake and therefore alter the level of thyroid hormones. There is also scientific evidence that changes in thyroid hormone levels in a pregnant woman may be linked to changes in the neurodevelopment of her offspring.
Perchlorate dissolves easily, is relatively stable and is mobile in water. While it has often been detected in water supplies in close proximity to sites where solid rocket fuel is manufactured or used, there are also locations in the United States lacking a clearly defined source.
People are exposed to perchlorate primarily through eating contaminated food or drinking water. The Food and Drug Administration (FDA) Total Diet Study combines nationwide sampling and analysis of hundreds of food items along with national surveys of food intake to develop comprehensive dietary exposure estimates for a variety of demographic groups in the U.S. The complete set of FDA perchlorate data can be found here: http://www.fda.gov/Food/FoodborneIllnessContaminants/ChemicalContaminants/ucm077685.htm
Contact your local water supplier to find out if perchlorate is in your drinking water and what steps your utility is taking to reduce your exposure. If you don't know who your local water supplier is, the information should be included in your latest water bill.
Perchlorate cannot be removed by heating or boiling water, however a point-of-use reverse osmosis device could be used to effectively remove perchlorate from drinking water.
A number of options are available to drinking water systems to lower concentrations of perchlorate in the drinking water supply. In some cases, drinking water systems may be able to reduce concentrations of perchlorate by closing contaminated wells or changing rates of blending of water sources.
Perchlorate can be removed using a number of advanced treatment technologies. Each technology has advantages and disadvantages depending on the level of perchlorate present in the source water, removal goals, other water quality parameters, competing treatment objectives, and treatment waste disposal options. Regenerable and single-pass ion exchange, reverse osmosis, and fixed- and fluidized-bed biological treatment can all remove perchlorate from drinking water sources.
These treatment technologies are used by some public water systems today and should be carefully designed and maintained to ensure that they are effective for treating perchlorate.
Additional information regarding steps water systems can take to address perchlorate in drinking water is available at https://www.epa.gov/sites/production/files/2020-05/documents/perchlorate_recommendations_for_pws_5.14.20.pdf
If you are concerned about the possibility of perchlorate in your drinking water and you are served by a private well, EPA recommends testing your drinking water. Approved laboratories can analyze a sample of your water to determine whether perchlorate is present and at what concentrations. More information about private wells can be found here: http://www.epa.gov/privatewells.
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Last updated on January 5, 2024