In last week's assembly meeting, Borough Manager Lisa Von Bargen reported that the city had recently been informed by the Alaska Department of Environmental Conservation that they had surpassed allowable levels of HAA5 in the water supply. HAA5, or Haloacetic Acids, is a byproduct of organic material in the water being treated with chlorine during the disinfection process.
"It is important to remember organic material is always present in the source water treated for Wrangell's drinking water," reads a Sept. 24 press release from the city. "The organic material load changes throughout the year, typically starting to increase in the fall. This year Wrangell has experienced a higher than normal load of organic material, and earlier in the year than typical."
The maximum contamination levels (MCLs) for disinfection byproducts like HAA5 are established by the EPA, according to the press release. The MCL for HAA5 is 60 parts per billion. The press release goes on to state that compliance with the MCL levels is based on a locational running annual average of water samples taken during the last four calendar quarters. With the latest test results from August, the press release reads, Wrangell's water has a locational running annual average of 80.1 parts per billon. Von Bargen clarified, in an email to the Sentinel, that this is 20.1 micrograms over the limit.
The press release goes on to state, at several points, that this is not an emergency. The city would have notified the public within 24 hours if it were. Staff at the water department are working with ADEC to adjust local treatment processes to reduce the amount of organic material in the water before the introduction of chlorine. The press release adds that the city will be introducing a "more robust testing regime" to check HAA5 levels more often than mandated. HAA5 levels in the water were already dropping, the press release reads. Von Bargen said that the next scheduled test is in November, but they will work with ADEC to test prior to that
"If you have a severely compromised immune system, have an infant, are pregnant or are elderly, you may be at increased risk and should seek advice from your health care providers about drinking this water," the press release reads. "You may continue to drink and use water normally. If you feel you are at increased risk there are two primary options for reducing the level of HAA5 in your drinking water: 1) drink bottled water, or 2) purchase a filter (such as Brita) that is carbon activated (has charcoal) to filter drinking water. Boiling water will not remove any HAA5."
Von Bargen went into some more detail about operational changes to lower HAA5 levels at the water department. For one thing, she said that the water department's staff will be vigilant regarding chlorine levels, making sure there is enough in the water to disinfect it, while also minimizing the potential to create byproducts like HAA5. Ozone generators have also been adjusted for the maximum possible output, she wrote, which will allow for more removal of organic material before filtration begins. She also said, in an email, that the water flow through the plant has been altered to slow down the average peak flow of raw water.
"This will allow for better contact time for the ozone to work on the organics within the raw water before filtration," Von Bargen wrote. "This will lower byproduct potential, and formation within the system. This change will require significantly more filter maintenance at the plant."
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