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Microbiological and Chemical Exposure Assessment Staff

Gerard N. Stelma Jr.

Title: Senior Science Advisor

EPA Division: Microbiological and Chemical Exposure Assessment Research Division

EPA Branch: Microbial Exposures Research Branch

Dr. Stelma’s research has focused on identifying virulence factors in opportunistic bacterial pathogens found in water and foods, investigating their roles in pathogenesis and developing tests to distinguish virulent strains from avirulent strains. He has also worked on developing monitoring methods for waterborne bacterial pathogens and indicators of fecal contamination. In addition, he has participated in investigations of sources of environmental exposures to pathogenic mycobacteria. Currently, he is working on a rapid cultural technique for detecting pathogenic E. coli in large volumes of water and a rapid DNA-based technique for monitoring recreational waters. The current studies are being performed through CRADAs with two small companies.


  • Ph.D. Microbiology, Michigan State University, East Lansing, MI, 1974
  • B.S. Biology, University of Michigan, Ann Arbor, MI, 1965

Professional Experience:

  • NIH Postdoctoral Fellow, Purdue University, West Lafayette, IN, 1976-1978
  • NIH Postdoctoral Trainee, University of Wisconsin, Madison, WI, 1976-1978
  • Research Microbiologist, US FDA, Cincinnati, OH, 1978-1987
  • Research Microbiologist, USEPA, Cincinnati, OH, 1987-1988
  • Branch Chief, USEPA, Cincinnati, OH, 1988-2004
  • Senior Science Advisor, USEPA, Cincinnati, OH, 1988-2004

Professional Societies and Affiliations:

  • Sigma Xi-The Scientific Research Society
  • American Society for Microbiology
  • International Society of Exposure Science

Select Awards and Honors:

  • USEPA STAA Award, Level II, 2009
  • USEPA STAA Award, Level II, 2009

Select Presentations:

  • An introduction to virulence factor activity relationships. EPA/NHSRC Workshop on quantitative structural activity relationships (QSARs) and virulence factor activity relationships (VFARs), Cincinnati, OH, 2006.
  • The new microbial source tracking manual. USGS Regional meeting, Columbus OH, 2005
  • The new microbial source tracking manual. Water Technology Conference, San Antonio, TX, 2004.
  • The new USEPA Microbial Source Tracking Manual. US EPA National Beaches Conference, San Diego, CA. 2004

Published & Presented Research (1999-Present)

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