Mechanisms Contributing to Pathogen Survival in Drinking Water Distribution Systems

EPA Grant Number: U916012
Title: Mechanisms Contributing to Pathogen Survival in Drinking Water Distribution Systems
Investigators: Dunahee, Nathaniel K.
Institution: University of Illinois at Urbana-Champaign
EPA Project Officer: Lee, Sonja
Project Period: January 1, 2001 through January 1, 2004
Project Amount: $102,000
RFA: STAR Graduate Fellowships (2001) RFA Text |  Recipients Lists
Research Category: Academic Fellowships , Engineering and Environmental Chemistry , Fellowship - Civil/Environmental Engineering


The objectives of this research project were to: (1) determine whether the spores of Bacillus subtilis, selected as a nonlethal surrogate for its highly lethal cousin, Bacillus anthracis, are inactivated in boiling water; and (2) assess whether aerosols formed in boiling processes created potential routes for dispersal of viable airborne spores.


Several different strains of Bacillus spores were considered and could have been used for the experiments. Different Bacillus strains vary in heat resistance, and it is difficult to estimate which would give the closest absolute resistance match to B. anthracis. However, the linear portions of temperature-driven first-order inactivation rate data for any thermally resistant Bacillus strain can provide useful insight to the anticipated inactivation-rate behavior of B. anthracis, with B. subtilis being one of the more widely accepted nonlethal surrogates.

Although many potential biological agents might be employed in terrorist attacks on water-supply infrastructures, B. anthracis is considered to be one of the most likely choices for several reasons. First, B. anthracis is highly lethal, with approximately 100 million lethal doses per gram of anthrax material. Second, highly concentrated (e.g., 10111013 spores per liter) B. anthracis suspensions can be produced in large quantities at low costs using relatively basic and readily available technology. Third, this spore-forming organism can be stored almost indefinitely, remaining viable for several decades under varying environmental conditions. Although a virus or other agent also might be used, few are able to match Bacillus spores in terms of chemical and thermal resistance, extreme potency, low barriers to production, ease of weaponization, and storage durability over extended periods of time.

Supplemental Keywords:

fellowship, Bacillus subtilis, Bacillus anthracis, drinking water, distribution systems, Bacillus inactivation.

Progress and Final Reports:

  • 2001
  • 2002
  • Final