Levels of a disinfectant byproduct in Wrangell's water supply are still a little above federal standards, the municipality reported Jan. 11, but are in decline.
The presence of haleocetic acids (HAA5) were announced in late September. The levels were triple federal Environmental Protection Agency standards in the regular quarterly test in August, then down to double the standard in a special test in October, the city reported.
November's test sample for HAA5 came in at 70 parts per billion (ppb), just above the EPA standard of 60 ppb.
In response to the presence of HAA5, the city's water department took several steps to lower the amount of organic material in the water. This included slowing down the water treatment process to allow more contact time between the water and the ozonation and filtration systems. The city will also be conducting more regular testing for the first few months of 2021.
The city's Jan. 11 press release explained that HAA5 is a type of disinfection byproduct. It is formed when any remaining organic material in water combines with a disinfectant like chlorine. The presence of excessive HAA5 in the water is not an emergency, the city said, adding that the EPA has indicated it takes years of drinking water with HAA5 to experience symptoms, such as an increased risk of cancer or problems with the central nervous system, liver or kidneys.
Anyone with concerns is encouraged to use charcoal filters for their drinking water, or to drink bottled water. The press release also encourages the elderly, pregnant women or people with compromised immune systems to seek advice from their health care providers.
"Wrangell's 'official' HAA5 level is based on an annual running average called the Locational Running Annual Average (LRAA)," the city's press release said. "The November 2020 sample is averaged with the results from August 2020, and the previous two quarterly samples from May and February 2020 to determine the LRAA. The new LRAA including the November sample results is 79.9 ppb."
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