Most Nebraska livestock lagoons don't pollute groundwater, according to a two-year study by the University of Nebraska.

Researchers reviewed 26 swine, dairy and beef cattle lagoons at 13 sites in central and eastern Nebraska. Researchers tested nearby groundwater to assess the potential of the lagoons to threaten groundwater quality. Twelve of the 13 sites were in use and 10 of the 12 active sites sampled got a clean bill of health, says Roy Spalding, director of the university's water sciences laboratory. About 85% of Nebraskans drink groundwater.

Nebraska's Institute of Agriculture and Natural Resources sampled each of the lagoons and adjacent groundwater four times during the spring and fall from 1999-2001. High concentrations of chloride and ammonia point to groundwater contamination from livestock lagoons, says Spalding.

Groundwater beneath two of the sampled lagoons contained higher levels of ammonia and nitrate. They were both in areas prone to pollution because groundwater is less than 35 ft. below the surface and the soils are easily permeable, he observes.