Perchlorates are colorless and odorless salts that dissolve easily in water. There are five perchlorate salts that are manufactured in large amounts:
Perchlorates are very reactive chemicals that are used mainly in explosives, fireworks, and rocket motors. Among other places, perchlorates occur naturally in saltpeter deposits in Chile, where saltpeter is used to make fertilizer. Perchlorates are also used for making other chemicals and were used many years ago as a medication to treat an over-reactive thyroid gland.
Perchlorates can enter the environment in and around sites where rockets are made, tested, and taken apart. Perchlorates have also been found in milk and food. Factories that make or use perchlorates may also release them into soil and water. Perchlorates will not stay in soil and will wash away with rain water. Perchlorates do eventually end up in ground water. While it is not known exactly how long perchlorates last in water and soil, the information available indicates that it is a very long time.
Perchlorate exposure may occur in any of the following ways:
The health effects of perchlorate salts are due to perchlorate itself, and not to the other components (i.e., magnesium, potassium, ammonium, sodium, lithium).
Perchlorate affects the ability of the thyroid gland to take up iodine, an important chemical needed to make hormones that regulate many body functions after they are released into the blood. There is concern that people exposed to high amounts of perchlorate for a long time may develop a low level of thyroid activity (hypothyroidism). Low levels of thyroid hormones in the blood can lead to adverse effects on the skin, cardiovascular system, pulmonary system, kidneys, gastrointestinal tract, liver, blood, neuromuscular system, nervous system, skeleton, male and female reproductive system, and numerous endocrine organs.
In spite of these concerns, studies have shown that health problems are unlikely at lower levels of perchlorate exposure. For instance, in one study, healthy volunteers took 35 milligrams (mg) of perchlorate every day for 14 days, and showed no signs of abnormal functioning of their thyroid gland or any other health problem. Other studies involving workers exposed for years to approximately the same amount of perchlorates found no evidence of alterations in the worker's thyroids, livers, kidneys, or blood.
No studies have been performed with regard to perchlorate exposure and cancer in humans. However, long-term exposure to perchlorates induced thyroid cancer in rats and mice. Despite the finding of thyroid cancer in rodents, the National Academy of Sciences (NAS) has concluded that it is unlikely that humans share the same risk based on an understanding of the biology of human and rodent thyroid tumors.
Perchlorates have not been classified for carcinogenic effects by the Department of Health and Human Services (DHHS), the U.S. Environmental Protection Agency (EPA), or the International Agency for Research on Cancer (IARC).
It is very unlikely that perchlorates are present in the average home or apartment. However, families can reduce the risk of perchlorate exposure by drinking bottled water if they have concerns about the presence of perchlorates in tap water. If you live near a waste site that has perchlorates, you can reduce the risk of exposure by preventing children from playing in or eating nearby dirt.
Children are more likely to be affected by perchlorates than adults, because thyroid hormones are essential for normal growth and development. Although perchlorate has been found in breast milk, studies of thyroid function of babies and young children whose mothers were exposed to perchlorate in their drinking water have not provided convincing evidence of thyroid abnormalities associated with perchlorate. While thyroid gland problems have been found in newborn animals, there have been questions and concerns regarding the interpretation of these findings.
There are no routine medical tests to measure perchlorate in the body, but it can be measured in the urine with special tests. Because perchlorate leaves the body fairly quickly, perchlorate in urine only indicates recent exposure.
The EPA is currently undertaking efforts to determine if regulation of perchlorate in drinking water would represent a meaningful opportunity for reducing risks to human health. So far, the EPA has set a preliminary clean-up goal of 24.5 ppb for perchlorate in water.
Recently, Massachusetts became the first state to set drinking water and waste site clean up standards for perchlorate. Massachusetts set the standard at 2 ppb, and now requires most public water systems to regularly test for perchlorate.
If you or a loved one have experienced any symptoms or have developed any medical conditions related to perchlorate exposure, you should first seek immediate medical attention. In the event that you exposed to high levels of perchlorate at your place of work without adequate protection or in violation of government standards, you may wish to meet with an experienced attorney to discuss your options and to protect your right to a legal remedy for your injuries.
