Dr. Ian Pepper is a Regents Professor at the University of Arizona and also the Director of the University of Arizona Water and Energy Sustainable Technology Center (WEST). He is an environmental microbiologist whose research has focused on the fate and transport of microbial pathogens in air, water, soils and municipal wastes. His expertise has been recognized by membership on six National Academy of Sciences Committees. Dr. Pepper is a Fellow of the American Association for the Advancement of Science, the American Academy of Microbiology, the Soil Science Society of America, and the American Society of Agronomy. He is the author or co-author of seven textbooks and over 200 peer-reviewed journal articles.Dr. Charles P. Gerba is a Professor at the University of Arizona. He conducts research the transmission of pathogens through the environment. His recent research encompasses the transmission of pathogens by water, food and fomites; fate of pathogens in land applied wastes; development of new disinfectants; domestic microbiology and microbial risk assessment. He has been an author on more than 500 articles including several books in environmental microbiology and pollution science. He is a fellow of the American Academy of Microbiology and the American Association for the Advancement of Science. In 1998 he received the A. P. Black Award from the American Water Works Association for outstanding contributions to water science and in 1996 he received the McKee medal from the Water Environment Federation for outstanding contributions to groundwater protection. He received the 1999 Award of Excellence in Environmental Health from National Association of County and City Health Officials.