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United States Department of Agriculture

Agricultural Research Service

Yakov A. Pachepsky

Soil Scientist

Research Soil Scientist

Environmental Microbial and Food Safety Lab
10300 Baltimore Avenue
Building 173 Room 203, BARC-East
Beltsville, MD 20705
Phone 301.504.7468

photo of Dr. Pachepsky with visitors to BARC Public Field Day

  • 1987 Dr. Sc. in Soil Science. Soil Science Department, Moscow State University, Russia. Dissertation title: "Regularities and models of chemical transport in soils of arid and semiarid regions"
  • 1973 Ph. D. in Physics and Mathematics, Department of Mechanics and Mathematics, Moscow State University, Russia. Dissertation title: " One-dimensional problems in rock mechanics "
  • 1969 M. Sci. in Mechanics, Department of Mechanics and Mathematics, Moscow State University, Russia. Dissertation title: "One-dimensional problems of ground mechanics"

Professional Experience
  • 2001-pres. Soil Scientist, USDA-ARS Environmental Microbial & Food Safety Laboratory, Beltsville Agricultural Research Center, Beltsville, MD
  • 1999-2001 Research Physical Scientist, USDA-ARS Hydrology and Remote Sensing Laboratory, Beltsville Agricultural Research Center, Beltsville, MD
  • 1994-1999 Senior Research Scholar, Phytotron, Duke University, Durham, NC
  • 1992-1993 Visiting Research Scientist, University of Maryland, College Park, MD
  • 1990-1992 Professor, Soil Science Department, Moscow State University, Moscow, USSR.
  • 1988-1991 Research Leader , Institute of Soil Science and Photosynthesis, USSR Academy of Sciences, Puschino
  • 1985-1988 Lead Scientist, Institute of Soil Science and Photosynthesis, USSR Academy of Sciences, Puschino
  • 1975-1982 Senior Scientist, Institute of Agrochemistry and Soil Science, USSR Academy of Sciences, Puschino
  • 1972-1975 Junior Scientist, Institute of Agrochemistry and Soil Science, USSR Academy of Sciences, Puschino

Statement of Research

The purpose of the research is to discover, evaluate, and integrate knowledge about transport and fate of enteric pathogenic microorganisms affecting microbial quality of irrigation waters. New hypotheses and measurement strategies have to be developed to evaluate and quantify biological, chemical and physical factors and interactions affecting pathogen prevalence, fate and transport in irrigation waters. The research uses hydrologic and contaminant transport modeling, soil-landscape analysis, scaling methods, data mining, geographic information systems, and other relevant technologies to integrate pathogen fate and transport information in pathogen fate and transport models for development, evaluation, comparison, and selection of management practices to reduce or eliminate risk of preharvest microbial contamination of foods.

Collaborating Scientists
  • Daniel Shelton, Jeffery Karns, Jo Ann van Kessel, Ali Sadeghi, Craig Daughtry, Thanh Dao, Gregory McCarty, Vangimalla Reddy, Dennis Timlin, USDA-ARS, Beltsville, MD
  • Scott Bradford, USDA-ARS, Riverside, CA
  • David Goodrich and Carl Unkrich, USDA-ARS, Tucson, AZ
  • Frederick Pierson, USDA-ARS, Boise, ID
  • Mark Welz, USDA-ARS, Reno, NV
  • Jaehak Jeong and Jimmy Williams, Texas AgriLife, Temple, TX
  • Bin Gao and Rafael Muñoz-Carpena, University of Florida, Gainesville, FL
  • Feng Pan, University of Utah, Salt Lake City, NV
  • Andrey Guber, Michigan State University, East Lansing, MI
  • Jiri Simunek, University of California, Riverside, CA
  • Robert Hill, University of Maryland, College Park, MD
  • Thomas Nicholson and Ralph Cady, US Nuclear Regulatory Commission, Rockville, MD
  • Gene Whelan, Richard Zepp, and Marirosa Molina, US EPA, Athens, GA
  • Mikhail Kuznetsov and Alexander Yakirevich, Jakob Blaustein, Desert Research Institute, Sde Boker, Israel
  • Fariz Mikayilsoy, Igdir University, Igdir, Turkey
  • Martinus van Genuchten, University of Rio de Janeiro, Brazil
  • Miguel Angel Martin and Fernando San Jose Martinez, Technical University of Madrid, Spain
  • Krzysztof Lamorski and Cezary Sławinski, Institute of Agrophysics, Lublin, Poland
  • Karl Vanderlinden and Gonzalo Martinez, IFAPA, Seville, Spain
  • David Oliver, University of Stirling, Stirling, UK
  • Harry Vereecken, Heye Bogena, Johan Huisman, and Jan Vanderborght, Institute of Agrosphere, Jülich, Germany
  • Kyunghwa Cho, Ulsan National Institute of Science and Technology, Republic of Korea
  • Maria Leonor R.C. Lopes Assad, University of Sao Carlos, Brazil
  • Abhijit Nagchaudhuri and Chris Hartman, University of Maryland Eastern Shore, Princess Anne, MD

Professional Affiliations
  • American Society of Agronomy
  • Soil Science Society of America
  • American Association for the Advancement of Science
  • American Geophysical Union
  • International Society of Ecological Modeling
  • International Union of Soil Sciences

Interagency Research

  • Interagency agreement: "Predictive Assessment for Microbial Fate, Transport, and Exposure of Manure-Borne Indicators and Pathogens at Plot, Field, and Watershed Scales"

Recent Reviews

Recent Publications

Click here to see a full list of publications drawn from the ARS database for Yakov Pachepsky, with access to an abstract/summary for each publication.

Current Parent Project
Pathogen fate and transport in irrigation waters

The presence of pathogenic microorganisms in irrigation waters is considered to be a potentially important factor in the preharvest contamination of fresh produce. Many of the essential pathogen fate and transport processes associated with irrigation are currently not well understood or modeled. This project focuses on (a) elucidating and quantifying mechanisms and factors controlling pathogen and indicator bacteria fate and transport from animal sources to irrigation water sources and via irrigation water delivery systems, and (b) developing models and computer-based tools to recommend and implement site-specific diagnostics, monitoring, and prediction of the fate and transport of pathogen and indicator bacteria in irrigation water sources and via delivery systems. An integrated approach including laboratory research, field research at irrigation systems, and mathematical modeling is used. Experiments and monitoring are carried out to (a) understand and quantify pathogen and indicator bacteria fate in potential pathogen reservoirs associated with irrigation systems, such as bottom sediments in surface waters, and biofilms in irrigation equipment, and (b) microbial exchange between these reservoirs and flowing or stagnant waters. Mechanistic models are developed to allow for (a) analyzing possible changes in pathogen and indicator bacteria concentrations along hydrologic pathways from animal sources to fields, and (b) improving resource allocation to monitor pathogen and indicator bacteria occurrence along the pathways. A broad collaboration is envisaged to support the development of methods for the characterization of the microbial ecology of irrigation systems, for monitoring and survey studies, and for collecting data for model validation and assessment.

Flowchart - pathogen fate and transport in irrigation water for production of fresh produce

Interagency project:
Model Abstraction Techniques for Soil Water Flow and Transport
This project tests the model abstraction (MA) at the watershed scale. The MA is defined as a methodology for reducing the complexity of a simulation model while maintaining the validity of the simulation results with respect to the question that the simulation is being used to address. MA explicitly addresses uncertainties in both model structure and parameters. We are using the systematic and comprehensive protocol for implementing the MA that includes:
  1. defining the conceptualization of the hydrologic model and the questions to be answered
  2. determining the significant features, events and processes to be abstracted
  3. selecting applicable MA techniques
  4. identifying MA simplifications of complex representations that may provide substantial gain
  5. evaluating the base model for additional simplifications of complex representations.

MA can resolve:
  • difficulties in obtaining reliable calibration of the base model
  • error propagation by introducing uncertainties into the key outputs
  • difficulties in understanding errant simulations results of the base model
  • excessive resource requirements for simulating complexities in base model
  • the need for incorporating the base model in repetitive risk assessments of multimedia environmental model
  • the goal for making the modeling process more transparent and tractable
  • the need in justifying the use simpler model rather than overly complex model

The MA benefits include:
  • improving reliability of modeling results
  • making the data selection and input more efficient
  • enabling risk assessments to be run and analyzed with much quicker turnaround, with the potential for allowing further analyses of problem sensitivity and uncertainty
  • enhancing communication of simplifications resulting from appropriate model abstractions which facilitates decision-making and informing the public

Environmental Fate and Transport Research - Download Code

Computer code mentioned and used in peer-reviewed publications authored by the EMFSL Environmental Fate and Transport research group is now available online. Written mostly in FORTRAN, the code is available for reuse and modifications. PC executables, source code, and PDF files for manuals and article reprints are provided.

Environmental Research to Improve Food Safety
a film by Ludmila Pachepsky

In this 15-minute film about research on the fate and transport of pathogenic bacteria in the environment, EMFSL scientists describe their research that uses a rainfall simulator and a special lysimeter site to investigate how bacteria can infiltrate into soil or run off with surface water depending on rainfall and vegetation conditions.

Click here to watch the film or read the film transcript.

image of Dr. Dan Shelton image of overhead view of experimental lysimeter site image of researchers working at experimental site image of Dr. Yakov Pachepsky

Quick links to information from the ARS database

Click here to see a list of current projects for Yakov Pachepsky

Click here to see a list of publications for Yakov Pachepsky

Click here to see a list of ARS News articles for Yakov Pachepsky

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USDA-ARS Environmental Microbial and Food Safety Laboratory
Henry A. Wallace Beltsville Agricultural Research Center
Phone 301.504.5607 | Fax 301.504.6608

Last Modified: 1/7/2015
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