Factors controlling subsurface transport of manure-borne pathogens Carl H Bolster carl.bolster@ars.usda.gov USDA-ARS Animal Waste Management Research Unit Bowling Green, KY Important manure-borne pathogens Viruses Rotavirus, Adenoviruses Bacteria E. coli O157, Campylobacter spp., Salmonella spp., Listeria spp. Photos from Wikipedia Protozoa (parasites) Cryptosporidium parvum, Giardia lamblia Health concerns gastrointestinal distress death Manure has potential to contaminate air, water, and soil with pathogens Foodborne illnesses Fields fertilized with improperly treated manure Irrigating with contaminated water Runoff water Direct deposition (wildlife, escaped livestock) Waterborne illnesses Drinking water Recreation Photos courtesy Jason Simmons Photo from LabPlanet Blog
Pathogen transport pathways Haydon & Deletic. 2006. J. of Hydrol. 328: 467 480 Risk of pathogen contamination of groundwater supplies GW was previously thought to have low vulnerability No longer assumed EPA GW Rule Diagram from Groundwater Forum Fecal Indicator Bacteria (FIB) Pathogen monitoring is rarely conducted Too many pathogens, expensive, time consuming Instead, nonpathogenic fecal indicator bacteria If FIB are detected then water may be fecally contaminated GWR E. coli, enterococci, coliphage
Factors affecting pathogen/indicator movement through soils and aquifers Geochemical Soil solution ionic strength, composition, and ph Surface coatings on soil (Feand Al-oxides) Organic matter (including manure) present in solution and soil SOM Fe Straining Factors affecting pathogen/indicator movement through soils and aquifers Geochemical Soil solution ionic strength, composition, and ph Surface coatings on soil (Feand Al-oxides) Organic matter (including manure) present in solution and soil SOM Physical Pore-size distribution Flow rate Soil texture Presence of macropore flow Soil moisture content Fe Straining Unsaturated soil soil air water DeNovio et al. 2004. Vadose Zone Journal 3:338 351
Factors affecting pathogen/indicator movement through soils and aquifers Geochemical Soil solution ionic strength, composition, and ph Surface coatings on soil (Feand Al-oxides) Organic matter (including manure) present in solution and soil Biological SOM Physical Pore-size distribution Flow rate Soil texture Presence of macropore flow Soil moisture content Size Motility Survival Surface properties Surface charge & hydrophobicity Fe Straining Current Research Compare transport behavior of E. coli and C. jejuni Compare transport behavior of multiple E. coli isolates Bacterial transport studies
Comparing transport behavior of E. coli and C. jejuni 100 Percent Recovery 10 1 0.1 E. coli C. jejuni 0.01 Uncoated sand Fe-coated sand Al-coated sand Treatment Type Bolster et al. 2006, JEQ 35:1018 1025 Variability in E. coli isolated from swine lagoon Variability in E. coli isolated from swine lagoon 1 Model Attachment Parameter 0.1 0.01 SP1C10 SP1H01 SP2A12 SP2B07 SP2C04 SP3B03 SP4C08 SP4H03 Bolster et al. 2010, EST 44:5008 5014
Correlation between attachment rate and surface charge 0.5 r 2 = 0.72 Model Attachment Parameter 0.4 0.3 0.2 0.1 0.0 0-10 -20-30 -40-50 Cell charge (mv) Bolster et al. 2010, EST 44:5008 5014 Transport through soil of two swine isolates 0 2 Column depth (cm) 4 6 8 10 1e+5 1e+6 Retained cell conc Significance Large inter-strain diversity exists for E. coli Cell properties and transport behavior True even for strains isolated from the same source Results from experiments using single E. coli cannot be generalized to all E. coli Modeling of E. coli transport will require a distribution of attachment rates Is this variability good or bad for an FIB? Implications for bacterial source tracking
Why the concern? Total amount of manure produced in the U.S. exceeds 335 million tons dry matter yr -1 Photos courtesy of: Al Havinga and USDA (NRCS and ARS); FEMA; and EPA. Proper manure management is required to reduce risk of infection from manure borne pathogens Proper storage, treatment, and application methods Photos courtesy of John Loughrin and Jason Simmons Reducing leaching potential of pathogens from fields receiving manure Minimize water leaching below root zone Timing between water/liquid manure applications (die-off of pathogens) Consideration of water table depth
Acknowledgements Dr. Kim Cook USDA-ARS Dr. Sharon Walker UC Riverside