ST. PAUL, Minn. (AP) _ A new study from the University of Minnesota has found that home water softeners are sending a significant amount of salt into the state's lakes, streams and groundwater.

Reports say about 50 of the state's water bodies have chloride levels that exceed its water quality standards.

University researchers from the Water Resources Center created a chloride budget to estimate how much salt enters the environment each year from various sources.

Road salt was the largest source of chloride statewide, contributing more than 400,000 metric tons (440,900 tons) annually to the environment. The study ranks household water softeners as the fourth largest source, contributing about 140,000 metric tons (154,300 tons) of salt per year.

The study also says commercial fertilizer and manure are major sources of salt.