Determining sources of fecal pollution in a rural Virginia watershed with antibiotic resistance patterns in fecal streptococci
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Authors: C. Hagedorn, S. L. Robinson, J. R. Filtz, S. M. Grubbs, T. A. Angier, and R. B. Reneau, Jr.
Date: 1999
Journal: Applied and Environmental Microbiology
Volume: 65
Number: 12
Pages: 5522-5531
Summary of Methods: Antibiotics resistance in fecal streptococci was used to identify sources of fecal pollution in a rural Virginia watershed. A database of fecal streptococcus isolates was established from known human, livestock, and wildlife sources. Identification of the correct fecal streptococcus source for the entire database ranged from 84% for deer isolates to 93% for human isolates. To field test the method and the database, a watershed improvement project Page Brook in Clark County, VA (approximately 80 km west of Washington DC) was initiated in 1996. Water samples from surface water and ground water were collected monthly from November 1996 to February 1999 and were analyzed for contaminants within 24 hours.
Article Summary / Main Points: Stream samples from three collection sites were highly contaminated, and fecal streptococci from these sites were classified as being predominately from cattle, with small proportions from other sources. Modifying grazing management, to limit cattle access to the stream though off-site water development and fencing, decreased fecal coliform counts on these sites by 94%, dropping fecal streptococci contaminants from cattle to less than 45% of the total. Antibiotic resistance profiles in fecal streptococci can be used to reliably determine sources of fecal pollution, and water quality improvements can occur when efforts to address the identified sources are made. Comparison of 892 known-source isolates from that watershed against the database resulted in an average correct classification rate of 88%. Fecal coliform counts were higher during warm humid (May to Oct) weather and decreased in the cooler weather from November to April.
Vegetation Types: Other (includes Forest and Eastern)
MLRA Ecoregions: 128 Southern Appalachian Ridges and Valleys 130A Northern Blue Ridge
Agrovoc Control Words: Riparian zones Water quality Nonpoint pollution
Article Review Type: Refereed
Article Type: Experimental Research
Keywords: water quality, nonpoint source pollution, fecal coliform, bacteria, fencing, pollution source identification
Annotation: Though this study was conducted in the eastern vegetation type the finding are widely applicable to any vegetation type where identification of a source of fecal bacteria is desired. Identification of the pollution sources can aid in restoration of the water quality.
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