Chloride levels in many surface waters are increasing and pose an emerging environmental concern, since elevated chloride levels are harmful to aquatic life. Minnesota has 50 lakes, rivers, and streams with chloride water quality impairments, and chloride levels in groundwater are also increasing, particularly in urban areas.
Many communities in Minnesota are facing chloride issues, including impaired waters and elevated chloride in their wastewater treatment. It is very costly to remove chloride from water and wastewater, and there are no feasible means to remove it from the environment.
Communities and watersheds can take steps to manage their salt use and reduce their chloride inputs to the environment:
- Communities with elevated chloride in their wastewater treatment plant discharge will look to municipal sources, such as households, industries, and commercial organizations. Infiltration of road salt may also be a chloride source.
- Communities with water impairments can also examine nonpoint sources, particularly road salt, but also dust suppressant, potash fertilizer, and livestock operations.
- Contact city or county public works officials for estimates on road salt and dust suppressant use.
- Find out if there are wastewater treatment plants or industries that are discharging to the water body.
- Identify any major industries that discharge chloride and estimate their loading using monitoring data.
- Find out the water hardness from the water utility.
- If the water is very hard (>10 grains per gallon), water softeners may be an important chloride source. Estimate how many households soften by conducting a survey or contacting water quality professionals.