Water Resources Research Act Program

Details for Project ID 2004NC41B

Arsenic and Heavy Metal Leaching Potential from Broiler Litter Stockpiled on Bare Soil

Institute: North Carolina
Year Established: 2004 Start Date: 2004-03-01 End Date: 2005-08-31
Total Federal Funds: $48,666 Total Non-Federal Funds: $97,334

Principal Investigators: Sanjay Shah, Garry Grabow, David Hardy, Dean Hesterberg, Rodney Huffman, James Parsons

Project Summary: Poultry production is an important agricultural enterprise in North Carolina. In addition to nitrogen (N) and phosphorus (P), metals such as arsenic (As), copper (Cu), manganese (Mn), and zinc (Zn) are added to poultry feed for dietary or therapeutic purposes. While some of these constituents are assimilated by the birds, As is almost totally excreted. In fact, poultry litter contains (on a dry-weight basis) up to 77 mg As/kg, 1000 mg Cu/kg, and 670 mg Zn/kg. Stockpiling poultry litter on bare, sandy soils before application to corn in spring and winter wheat in fall is common in the Coastal Plain of North Carolina. Because these stockpiles are essentially point sources for nutrients, As, and heavy metals, this practice could result in enhanced mobility of these constituents, which could impact groundwater quality and cause adverse health and environmental effects. In this study, temporal changes in constituent (As species, N species, P species, carbon, Cu, Mn, and Zn) concentrations in broiler litter stockpiles as well as in underlying and adjacent soil at various depths will be investigated. Four broiler litter stockpiles will be monitored during summer through fall and four more during fall through spring; in each batch, two stockpiles will be monitored under natural rainfall and two more under simulated rainfall. Litter analyses at the beginning and end of stockpiling will provide information on the impact of stockpiling and environmental conditions on the transformation and mobility of constituents. Soil sampling in the upper 0.9 m (3 ft) of soil in different depth increments, before and after stockpiling, will provide information on the leaching of litter constituents in the soil and its potential impact on groundwater quality over time. Further information related to As mobility as influenced by soil phosphate concentrations will also be obtained.