Perchlorate - Environmental Presence

Environmental Presence

Low levels of perchlorate have been detected in both drinking water and groundwater in 26 states in the U.S., according to the Environmental Protection Agency. In 2004, the chemical was also found in cow's milk in California with an average level of 1.3 parts per billion ("ppb" or µg/L), which may have entered the cows through feeding on crops that had exposure to water containing perchlorates. According to the Impact Area Groundwater Study Program, the chemical has been detected as high as 5 µg/L in Massachusetts, well over the state regulation of 2 µg/L.

In some places, perchlorate is detected because of contamination from industrial sites that use or manufacture it. In other places, there is no clear source of perchlorate. In those areas it may be naturally occurring, or could be present because of the use of Chilean fertilizers, which were imported to the U.S. by the hundreds of tons in the early 19th century. One recent area of research has even suggested that perchlorate can be created when lightning strikes a body of water, and perchlorates are created as a byproduct of chlorine generators used in swimming pool chlorination systems. In 2010, perchlorate was found at the 1000ppb levels in a vast section of Antarctica, with implications that it is formed naturally and globally on Earth and, it is presumed, on Mars most likely by photochemical reactions in the atmosphere.

Fireworks are also a source of perchlorate in lakes.