HR: 14:45h
AN: B53A-06    [Abstracts]
TI: Potential Impacts of Organic Wastes on Small Stream Water Quality
AU: * Burke, R A
EM: burke.roger@epa.gov
AF: Roger A. Burke, USEPA/NERL 960 College Station Road, Athens, GA 30605 United States
AU: Molinero, J
EM: jmolinero2002@yahoo.com
AF: Jon Molinero, National Research Council c/o USEPA 960 College Station Road, Athens, GA 30605 United States
AB: We monitored concentrations of dissolved organic carbon (DOC), dissolved oxygen (DO) and other parameters in 17 small streams of the South Fork Broad River (SFBR) watershed on a monthly basis for 15 months. The subwatersheds were chosen to reflect a range of land uses including forested, pasture, mixed, and developed. The SFBR watershed is heavily impacted by organic wastes, primarily from its large poultry industry, but also from its rapidly growing human population. The poultry litter is primarily disposed of by application to pastures. Our monthly monitoring results showed a strong inverse relationship between mean DOC and mean DO and suggested that concentrations of total nitrogen (TN), DOC, and the trace gases nitrous oxide, methane and carbon dioxide are impacted by organic wastes and/or nutrients from animal manure applied to the land and/or human wastes from wastewater treatment plants or septic tanks in these watersheds. Here we estimate the organic waste loads of these watersheds and evaluate the impact of organic wastes on stream DOC and alkalinity concentrations, electrical conductivity, sediment potential denitrification rate and plant stable nitrogen isotope ratios. All of these water quality parameters are significantly correlated with watershed waste loading. DOC is most strongly correlated with total watershed waste loading whereas conductivity, alkalinity, potential denitrification rate and plant stable nitrogen isotope ratio are most strongly correlated with watershed human waste loading. These results suggest that more direct inputs (e.g., wastewater treatment plant effluents, near-stream septic tanks) have a greater relative impact on stream water quality than more dispersed inputs (land applied poultry litter, septic tanks far from streams) in the SFBR watershed. Conductivity, which is generally elevated in organic wastes, is also significantly correlated with total watershed waste loading suggesting it may be a useful indicator of overall watershed waste loading. Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
DE: 1045 Low-temperature geochemistry
DE: 1055 Organic geochemistry
DE: 1615 Biogeochemical processes (4805)
DE: 1806 Chemistry of fresh water
SC: Biogeosciences [B]
MN: 2005 Joint Assembly