Managing Livestock Waste
To Protect Groundwater

By BRAD RUCKMAN, Illinois Environmental Protection Agency

Groundwater serves as a primary source of drinking water for many Illinois residents, making it essential to maintain the integrity of this resource. In rural areas livestock operations can pose a threat to groundwater. Nitrates and fecal bacteria derived from livestock waste can render the groundwater unusable for domestic purposes.

Nitrates are formed from organic nitrogen contained in manure. This transformation occurs through a series of biological processes. The nitrates that are formed are water soluble and readily move downward through the soil. This movement of nitrates through the soil is known as leaching.

Potable water with nitrate-nitrogen concentrations higher than 10 milligrams per liter (mg/l) is considered unsafe for daily consumption by infants. Nitrates ingested by infants up to six months of age can cause serious consequences, or even death, among susceptible children. The health hazard from nitrate results from its ability to combine with hemoglobin in the blood to form methemoglobin, which does not carry oxygen. Affected children develop "blue baby" characteristics and in extreme cases could die of suffocation from oxygen deprivation.

Fecal coliform bacteria are common to the intestinal tract of man and animals. The bacteria's presence in water indicates that potentially more harmful (pathogenic) bacteria may also be present. In some cases it may be possible for bacteria to infiltrate groundwater, but in most instances the route of contamination is via intrusion at a wellhead or seepage through a faulty well casing. This can occur when the well is close to and downgradient from the feedlot or waste-handling system.

Producers can prevent groundwater contamination by addressing the following recommendations and requirements.

The Illinois Groundwater Protection Act (Act) prohibits facilities used for handling livestock waste from being constructed within 200 feet of a potable well. If, however, the owner of the well and the livestock facility are the same, the set-back may be reduced to as close as 75 feet, but this is not recommended.

All new water wells in Illinois must be established according to construction codes administered by the Illinois Department of Public Health. Most older wells do not meet Illinois code, especially those with well casings consisting of brick, stone, concrete blocks, or other porous materials. Many wells of this type can be found near or sometimes in feedlots throughout the state. These wells should be properly sealed so as to prevent accidental introduction of contaminants into groudwater. Section 920.120 of the Illinois Water Well Construction Code prescribes the procedures for sealing abandoned wells.

The Illinois Livestock Waste Regulations (35 Ill. Adm. Code Part 501, Subtitle E) state that new live stock management facilities or new livestock wastehandling facilities located on soil types or geological formations where the deposition of livestock waste is likely to cause groundwater pollution shall be constructed in such a way that pollution will be prevented, so supplementary measures shall be adopted that will prevent pollution.

To prevent groundwater contamination from occurring, locate such facilities away from water wells beyond the required set-backs if necessary, and avoid areas with high water tables. It is also recommended that a clay liner or bentonite be utilized for all liquid manure storage systems to help prevent leaching. Fabricated manure holding tanks and pits must also be kept impermeable.

Temporary manure stacks must be constructed or established and maintained in a manner to prevent runoff and leachate from entering surface or groundwater. Temporary manure stacks are subject to the 200 foot set-back required by the Act.

There is also a potential for groundwater contamination from the field application of livestock waste. If manure is applied to cropland upslope from a water well, then precipitation runoff can carry the waste toward the wellhead. Livestock waste that is injected into

November 1991 / Illinois Municipal Review / Page 11

the soil near water wells may also drain to the well through underground flow systems. If livestock waste application rates exceed the recommended agronomic rate (defined as the annual application rate of livestock waste and/or commercial fertilizer that is necessary to achieve a reasonable crop yield without exceeding crop nutrient requirements), nutrients and other pollutants not taken up by growing crops can leach below crop rooting zones and into groundwater resources. In consideration of these factors, livestock wastes should not be applied within 150 feet of any water well.

For assistance in design and establishment of livestock waste-handling facilities, producers can consult their local Soil Conservation Service or Cooperative Extension Service.

For further information regarding livestock waste management and governing regulations, contact one of the Illinois Environmental Protection Agency (IEPA) agricultural engineers at the regional office listed below or contact the lEPA's agricultural adviser in Springfield at (217) 782-3397.

Rockford Regional Office (815) 987-7755 Peoria Regional Office (309) 693-5463 Champaign Regional Office (217) 333-8361 Springfield Regional Office (217) 786-6892 Marion Regional Office (618) 997-4371 (For more information on this article, contact Brad Ruckman, (217) 785-0830.)

Page 12 / Illinois Municipal Review / November 1991