North Carolina School Finds Contaminated Drinking Water Perchlorate
“On Dec. 18, elevated levels of perchlorate were discovered in drinking water at Lake Norman High School in Iredell County, N.C. The Iredell-Statesville School Board has decided to provide bottled water to students and staff until further testing of the water quality is completed.
According to a press release, the school found that perchlorate levels at Lake Norman High School were particularly elevated compared to neighboring schools. While perchlorate levels are not regulated in North Carolina, the school system recognizes the risks and has opted to provide bottled water. The schools system hired an outside agency, Reliant Environmental, to test the district’s water quality following the discovery of elevated lead levels at a neighboring school.”
Source: Water Quality Magazine
What is Perchlorate?
Perchlorate is a naturally occurring and manufactured chemical anion (ClO4-). Perchlorate occurs naturally in arid states within the southwestern portioin of the United States, nitrate fertilizer deposits in Chile, and deposits of clay deposits rich in potassium and sodium salts, i.e., potash ore, in the United States. It also forms naturally in the atmosphere by a photochemical interaction between chloride and ozone in the atmosphere . Perchlorate is commonly used as an oxidizer in rocket propellants, munitions, fireworks, airbag initiators for vehicles, matches, and signal/road flares. The primary source of perchlorate is man-made.
People are exposed to perchlorate primarily through eating contaminated food or drinking water and perchlorate dissolves in water. FDA perchlorate data can be found here.
The EPA has not yet established a maximum contaminant level goal for perchlorate and the intermim health advisory can be found here. Massachusetts adopted a drinking water standard for perchlorate of 2 µg/L, and California promulgated a revised standard of 1 µg/L. In addition, states may impose clean-up standards related to the quality and use of the groundwater aquifer.
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.
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