LABORATORY STUDY OF TRACE ELEMENTS RELEASED FROM POULTRY LITTER: IMPLICATION FOR TRACE ELEMENT RELEASE WITHIN AGRICULTURAL WATERSHEDS OF LEBANON, CONNECTICUT

Lebanon is a farming community located in New London County, CT. It is the home to one of the biggest poultry farm in Connecticut with over 1.2 million chickens; and much of the poultry litter from this farm is often applied as fertilizer to various farmlands. This study examined the effect of dissolved organic matter in poultry litter leachate on the fate and transport of litter-derived elements, As, Cu, P and Zn using laboratory column experiments. Soil cores were collected using direct push methods from an area of intense poultry production similar to Lebanon, CT. In the laboratory, we simulated the transport of litter derived trace elements in the vadose and saturated zones of the soil collected. Two types of influent solution were made for the column experiments, the first was the poultry leachate extracted using 25 ml of deionized water on 5 grams of litter; the second one was the simulated litter solution, containing similar concentrations of trace elements, major ions, similar pH, and ionic strength, but without dissolved organic carbon (DOC). Results of the experiments showed that DOC enhanced the mobility of all of the trace elements, but that even in the presence of DOC, 60-70% of Zn, As and P were retained within the sediment. Cu was fully mobilized in solution and was not retained in the soil. Patterns of breakthrough curves and mass calculations suggest that the behavior of these trace elements in the column is controlled by both adsorption (including competitive) to soil and complexation with DOC. The implication of these findings is that the presence of DOC in poultry litter in addition to the organic matter content, and mineralogy of soils and underlying sediment, could influence the mobility, distribution and concentrations of trace elements within agricultural watershed environment similar to Lebanon, CT