Dear Mr. Goodover and Board Members -
The Missoula City-County Health Board supports the resolution to require connection of all properties within the Seeley Lake Sewer District to the public sewer system as it becomes available. The Health Board is concerned about the nitrate levels in Seeley Lake’s groundwater and public sewer is a proven way to reduce the impact of septic system pollution in a community. However, in order to reap the benefit of public sewer, it is important that the number of connections be maximized.
Recent water quality data still show widespread elevated levels of nitrate in Seeley’s groundwater. Some results exceed l0 mg/L, which is the maximum allowable concentration of nitrate in groundwater in Montana. Studies have linked the nitrate pollution to the density of septic systems discharging wastewater in the area. Conventional septic systems do well at removing viruses and bacteria from wastewater but they do not remove nitrate.
Nitrate levels are regulated in state waters due to the potential risks it can present to both human and environmental health. Consuming drinking water with elevated concentrations of nitrate can impact the body’s ability to transport oxygen and result in severe illness or even death, especially in infants. Certain forms of cancer have also been linked to nitrate consumption. Fortunately, the majority of residents in the sewer district are not currently consuming high concentrations of nitrate in their drinking water because they get their water from the Seeley Lake public water system, which draws from the lake. However, Montana state law requires that the quality of state waters be protected equally for current and anticipated uses. In other words, Seeley’s groundwater quality is subject to the same water quality standards regardless of how it is currently being used.
Once introduced to surface waters, nitrate is primarily removed by aquatic plants. In surface waters, too much nitrogen can lead to excessive plant growth, which decreases oxygen levels, raises water temperatures, and can lead to significant declines in the overall health of a water body and the life it supports. This process is known as eutrophication and once a body of water becomes eutrophic it can be very difficult to reverse.
According to Montana Department of Environmental Quality’s discharge permit, the public system currently being proposed will remove approximately 85 percent of the nitrate from Seeley’s wastewater. This is very effective treatment that will help to ensure that state waters and public health are protected for years to come. However, properties not connected to the public sewer system will continue to discharge nitrate to groundwater at levels that may cause or contribute to further violations of state water quality laws.
We also want to recognize the District Board’s dedicated efforts to keeping this sewer project moving forward. Sewering a small community is not an easy task. We were very pleased to learn that this project is nearing the point of bidding and construction.
If you have any questions or concerns regarding this letter, or this matter in general, please feel free to contact the Health Department at any time.
Ross Miller, Chair
Missoula City-County Health Board - Missoula, Mont.
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