BACTERIOLOGICAL WATER QUALITY OF FORESTED AND PASTURED STREAMS RECEIVING LANDAPPLIED POULTRY LITTER
American Water Resources Association , 2003
McBroom, M.W., Chang, M., Wells, C.W.
Poultry production is a growing industry in East Texas, generating about 360,000 m tons of broiler litter each year as a by-product for application on pasturelands. Grab samples of fecal coliform (FC) and fecal streptococcus (FS) were collected monthly between March and December 1996 and FC and E-coli samples were collected weekly between July and October 2001 at six sites on the Waffelo and Terrapin Creeks in Nacogdoches County, Texas to assess possible impacts of poultry litter application on bacterial water quality. Sites were grouped by three pairs with each pair consisting of one upstream site in predominantly forested area and one downstream site in a pastured area receiving land application of poultry litter. All pastured watersheds had a 10 to 150 m buffer of riparian forest and/or unfertilized pasture between the stream and areas on which broiler litter was applied. FC concentrations exceeded the 200 cfu/100 ml contact recreation standards in more than 50% of observations, regardless of forested or pastured conditions. E-coli samples did not violate standards and has been shown to be a better indicator of fecal contamination. Current broiler litter land-application rates on pasturelands did not cause significantly higher FC concentrations than natural wildlife activities on forested watersheds. Water pH was the only parameter significantly correlated (r > 0.50) with FC in the study areas. No significant correlations were detected between FC and other aquatic parameters including stream discharge, temperature, salinity, specific conductance, and dissolved oxygen. The study suggests that background variation in bacteriological parameters may mask land-use practices, though a longer period of observations with greater sampling frequency at more study sites may reduce observed variation in the present study.