You are here:
Combining Watershed Variables with PCR-based Methods for Better Characterization and Management of Fecal Pollution in Small Streams
Citation:
PEED, L., C. T. NIETCH, C. A. KELTY, K. WHITE, J. C. BLANNON, M. C. MECKES, T. MOONEY, M. SIVAGANESAN, R. A. HAUGLAND, AND O. C. SHANKS. Combining Watershed Variables with PCR-based Methods for Better Characterization and Management of Fecal Pollution in Small Streams . Presented at ASM 109th General meeting, Philadelphia, PA, May 17 - 21, 2009.
Impact/Purpose:
To inform the public.
Description:
Culture- and PCR-based measurements of fecal pollution were determined and compared to hydrologic and land use indicators. Stream water samples (n = 235) were collected monthly over a two year period from ten streams draining headwatersheds with different land use intensities ranging from mostly forested, rural agricultural, to high-density residential. The sampling effort was part of a multidisciplinary program designed to characterize and manage water quality in the 1300 km2 East Fork Watershed of Southwestern Ohio. PCR-based methods included 14 PCR and quantitative real-time PCR (qPCR) assays that detect enterococci, E. coli, Bacteroidales as well as human- and bovine-specific genetic markers. Culture-based measurements of enterococci and E. coli cell densities were above water quality standards 50-100% of the time. An analysis of variance indicated that when there was ≥ 0.25 in of rainfall within 24 hr prior to sampling there was a significant increase in genetic marker concentrations for all qPCR assays (p < 0.05). All samples tested negative for cow and ruminant specific genetic markers, however, at least one human-specific qPCR assays tested positive for 29.4 to 90.9% of samples. Almost all samples tested positive for general fecal indicators (>94%) confirming the presence of fecal pollution in all streams over the sampling period. Preliminary data analyses have demonstrated that combining PCR-based measurements of fecal contamination with hydrologic and land use indicators provided a more complete understanding of microbial pollution in areas of the East Fork Watershed, leading to more focused watershed management efforts.
