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What have we learned after more than 30 years of research into the effects of sunlight, water type, nutrients, temperature and biotic interactions on decay of fecal indicators and pathogens?
Korajkic, A., P. Wanjugi, AND V. Harwood. What have we learned after more than 30 years of research into the effects of sunlight, water type, nutrients, temperature and biotic interactions on decay of fecal indicators and pathogens? 2018 UNC Water Microbiology Conference, NC, Chapel Hill, May 22 - 24, 2018.
This presentation is a literature review of the effect of different environmental parameters on decay of various indicator and pathogen microorganisms.
Many waterborne pathogens originate in the gastrointestinal tract of humans or other animals (the primary habitat), and enter water bodies (secondary habitat) via direct fecal deposition, runoff, or sewage discharges. Fecal indicator bacteria (FIB) such as fecal coliforms, enterococci, E. coli, and microbial source tracking (MST) markers are used to indicate the presence, source, and level of this contamination in water. The trajectory (growth, stasis, or death) and rate of change in FIB/MST/pathogen populations in secondary habitats has profound implications for our understanding of human health risk from fecal contamination. These implications affect best practices such as wastewater treatment, ambient water quality assessment, modeling of water quality, risk assessment, and management of environmental waters. The literature abounds with studies of the fate of fecal-associated viruses, bacteria, and protozoa in water, many of which have seemingly conflicting conclusions. The objective of this project is to systematically examine the literature on the effect(s) of select environmental parameters: 1) sunlight, 2) water type, 3) nutrients, 3) temperature, and 4) biotic interactions on inactivation, survival, and growth of fecal-associated microorganisms in aquatic environments. Constraints to study inclusion mandated that they must have been conducted in a natural or simulated aquatic habitat, excluding engineered or completely simplified habitats such as wastewater treatment plants and drinking water. All included studies needed to juxtapose control vs treatment (e.g. sunlight exposed vs dark controls) or two different treatments (e.g. fresh vs marine water) and report findings in some quantitative manner, such as decay rate or log10 reduction.
Record Details:Record Type: DOCUMENT (PRESENTATION/SLIDE)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL EXPOSURE RESEARCH LABORATORY
EXPOSURE METHODS & MEASUREMENT DIVISION
MICROBIAL EXPOSURE BRANCH