Kimberly M. Dreaden, Aurelien Desaunay, and Jeffrey L. Ullman

EFFECT OF VEGETATION ON BACTERIAL
TRANSPORT AND REMOVAL IN AGRICULTURAL SOILS
Kimberly M. Dreaden, Aurelien Desaunay, and Jeffrey L. Ullman
Department of Agricultural & Biological Engineering, University of Florida
Questions to Answer
Introduction
In the U.S., waterborne pathogens cause 19.5 million
illnesses per year, and are the number one cause of
water quality impairment (Bridge, 2010; EPA, 2013).
The Southeast has 4,227 waterbodies that fail to meet
bacterial water quality standards. Agriculture is the
primary source of pathogen loading in surface waters,
originating directly from livestock operations or
through the land application of manure. There is a
critical need to develop and evaluate best management practices (BMPs) to mitigate bacterial transport
from agricultural operations to the environment.
Approach
The goal of this research is to understand the
mechanisms affecting the fate and transport of
pathogenic bacteria in vegetated soil systems in order to improve agricultural BMPs to limit pathogen
movement in the environment.
1. How do the following effect the transport of bacteria in a VFS system:
* vegetation type
* soil type
* slope
2. How effective is a VFS system in attenuating bacteria?
3. What is the major mechanism involved in mitigating bacterial movement?
Source: Muñoz-Carpena
Photo: Oregon Dept of Ag
Photo: K.M. Dreaden
Vegetative filter strips (VFSs) are a BMP that has
been shown to effectively attenuate the transport of
nutrients and sediments from agricultural operations.
Limited research has focused on evaluating the efficacy of VFSs in bacterial removal.
Vegetated soil boxes will be used to investigate
bacterial fate and transport. E. coli MG1655 modified with green fluorescent protein (GFP) will serve
as a model organism, which can be distinguished
between colloid and the indigenous bacteria. Samples collected from subsurface flow and runoff will
be examined using plating techniques.
References
* Environmental Protection Agency. 2013. National summary of impaired
waters and TMDL information. Watershed Assessment, Tracking and Environmental results. Found at: http:// iaspub.epa.gov/waters10/ att
ains_nation_cy.control?p_report_type=T
* Bridge, J. 2010. Engaging with the water sector for public health benefits:
waterborne pathogens and diseases in developed countries. World Health
Organization. Found at: http:// www.who.int/bulletin/ volumes/88/11/09072512/en/
* Muñoz-Carpena, R. 2012. VFSMOD-W: Vegetative Filter Strip Modeling Sys
tem. Found at: http://abe.ufl.edu/carpena/vfsmod/