Impact of Waste Lagoons on Groundwater

Growing concern over possible adverse health and environmental impacts of livestock waste lagoons on groundwater and soil quality has prompted the Nebraska Department of Environmental Quality (NDEQ) to request assessments from several Nebraska livestock operations.

The operations have volunteered to be assessed and were approved to participate in the project, which is being conducted by the Water Sciences Laboratory (WSL) at the University of Nebraska-Lincoln. The WSL will provide an impartial evaluation of the possible environmental impacts of livestock waste lagoons, said hydrochemist Roy Spalding, who directs the WSL.

Nine producers volunteered to participate in the monitoring study. Since some sites have more than one lagoon, a total of 14 lagoons will be monitored, Spalding said. The size of the monitored lagoons range from a capacity of approximately 100,000 gallons to one of approximately nine million gallons.

"The sites involve a spectrum of vulnerabilities to contamination such as soil types and depths to water. The lagoons also cover a range of ages from new construction to one that is 26 years old," Spalding said.

Each site will have both up-gradient and down-gradient monitoring wells installed by WSL staff. Samples from monitoring wells will be collected twice per year for two years and will then be analyzed for nitrate-nitrogen, ammonia-nitrogen, chloride and dissolved organic carbon. WSL researchers and staff also are developing a procedure to analyze these groundwater samples for traces of antibiotics used in animal vaccines.

"There has been some concern that land applications (such as fertilizing crops) of water containing antibiotics may be promoting resistant bacterial strains. This ability to trace waste is particularly important in areas where contamination of groundwater may already exist from other agricultural operations," Spalding said.

The WSL will provide the NDEQ with an evaluation of the monitoring results. The two entities will develop a variety of educational materials from the project as a means of making results available and useable to producers, researchers, agencies, producer groups and the public.