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An Assessment of Fecal Contamination in Rural Streams Impacted by Litter Applications
Citation:
Lee, Y. J. AND M. MOLINA. An Assessment of Fecal Contamination in Rural Streams Impacted by Litter Applications. In Proceedings, 2009 Georgia Water Resources Conference, Athens, GA, April 27 - 29, 2009. University of Georgia, Athens, GA, 7.7.2, (2009).
Impact/Purpose:
The objective of this study was to evaluate transport of fecal materials into streams located in farms containing pastures with the presence (AH and DH) and absence (DF) of cattle using various source-specific PCR assays.
Description:
The objective of this study was to evaluate transport of fecal materials into streams located in farms containing pastures with the presence (AH and DH) and absence (DF) of cattle using various source-specific PCR assays. All pasture sites were fertilized with composted chicken litter. The riparian zones of the streams varied in vegeta-tion cover and type. General Bacteroidales (Bac32F) signatures were detected in 96.2% of the samples across all streams. Ruminant-specific Bacteroidales marker (CF128F) was detected in AH (56.9%) and DF (82.1%); however, chicken-specific metagenomic markers were not detected, indicating the absence or below-detection-limit-level of chicken fecal contamination in the streams. A bird-specific metagenomic marker, CP1-1, was only detected in one of the cattle pastures (AH) following broiler litter application combined with a rain event. Mul-tiple linear regressions (MLR) revealed that temperature and turbidity positively correlated with enterococcal density in AH and DF. No significant explanatory variable for enterococcal density was found in DH. This study suggests that although the general fecal marker was identified frequently in the streams, indicating a constant input of fecal material, the source of the contamination varied. This variability seem to be dependent on a variety of factors, such as the quality of the stream buffer strip, quality of the composted fertilizer, and the distance of the cattle to the stream.