Poultry litter is used on agricultural land because of its high nutrient content. The litter contains trace elements. With land application of litter, these elements may accumulate in the soil or plants, may be transported as run-off to surface water, or may be leached into groundwater. The objective of this research was to measure the concentrations of trace elements in soils fertilized with poultry litter. Soil was collected from three agricultural farms in Wicomico County, MD. These farms had a long history of poultry litter application. A nitric acid extraction was performed on soil samples collected to a depth of 60 cm. The concentrations of As, Cd, Cu, Mn, Pb, and Zn were determined using atomic absorption spectrophotometry. Arsenic, Cd, Cu, and Mn concentrations were higher in the manured fields than in the control fields. Lead and Zn concentrations did not significantly change with the application of poultry litter.
Poultry litter is a mixture of excreta, feed, feathers, and bedding material. Poultry litter is useful as a fertilizer due to the presence of nitrogen, phosphorus, and potassium. Litter is commonly used for growing corn, soybeans, potatoes, tomatoes, leafy vegetables, and cover crops. The aqueous leachate of poultry litter has been shown to exhibit toxicity to a variety of indicator organisms. The objective of this research was to identify classes of toxicants in the litter aqueous leachate. The aqueous extract of poultry litter was subjected to toxicity identification tests approved by the United States Environmental Protection Agency that use Ceriodaphnia dubia as the test organism. Tests performed included pH adjustment, filtration, aeration, C18 solid-phase extraction, EDTA addition, sodium thiosulfate addition, and extraction through zeolite. Zeolite extraction, filtration at low pH, and aeration at low pH reduced overall toxicity by 68, 20, and 22%, respectively. The major sources of toxicity appear to be ammonia and anionic organic compounds. Toxicity was apparently not due to the presence of heavy metals or oxidants.
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