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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Environmental Microbial & Food Safety Laboratory » Research » Publications at this Location » Publication #295420
Title: An integrated environmental modeling framework for performing quantitative microbial risk assessments

Author
item WHELAN, GENE - Us Environmental Protection Agency (EPA)
item KIM, KEEWOK - Us Environmental Protection Agency (EPA)
item PELTON, MITCH - Pacific Northwest National Laboratory
item SOLLER, JEFFRY - Soller Environmental, Llc
item CASTLETON, KARL - Pacific Northwest National Laboratory
item MOLINA, MARIROSA - Us Environmental Protection Agency (EPA)
item Pachepsky, Yakov
item ZEPP, RICHARD - Us Environmental Protection Agency (EPA)

Submitted to: Environmental Modelling & Software
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/19/2013
Publication Date: 8/1/2014
Citation: Whelan, G., Kim, K., Pelton, M., Soller, J., Castleton, K., Molina, M., Pachepsky, Y.A., Zepp, R. 2014. An integrated environmental modeling framework for performing quantitative microbial risk assessments. Environmental Modelling & Software. 55:77-91.

Interpretive Summary: Risk assessment, in general, is the characterization and estimation of potential adverse health effects associated with exposure of individuals or populations to hazardous materials or situations. With regard to recreational waters, adverse health effects may be caused by the ingestion of pathogens. Quantitative microbial risk assessment for recreational waters, or recreation water QMRA, establishes a relationship between the concentrations of pathogenic microorganisms in water and the probability of illness. QMRA employs two models: the exposure model and the infectivity model. Nowadays, microbial fate and transport models have reached a level of comprehensiveness and accuracy that allows predictions of site-specific exposure to pathogens, based on site-specific data on weather, soils, land use, agricultural management. We present the Framework for Risk Analysis in Multimedia Environmental Systems (FRAMES) which provides software technology for analysts to assemble appropriate models and databases that allows for site-specific, reproducible, flexible, transferable, reusable, and transparent QMRAs. An example application is presented that uses different models and databases registered with FRAMES. It illustrates how models are linked to assess the exposure to three pathogens (Salmonella enterica, Cryptosporidium spp., and E. coli 0157:H7) from six different contaminant sources. Receptor’s health risks are then evaluated. This work will be of use for environmental assessment analysts in that it provides technology for screening and ranking pathogens and their sources with respect to recreational health risks.

Technical Abstract: Standardized methods are often used to assess the likelihood of a human-health effect from exposure to a specified hazard, and inform opinions and decisions about risk management and communication. A Quantitative Microbial Risk Assessment (QMRA) is specifically adapted to detail potential human-health risks from exposure to pathogens; it can include fate and transport models for various media, including the source zone (initial fecal release), air, soil/land surface, surface water, vadose zone and aquifer. The analysis step of a QMRA can be expressed as a system of computer-based data delivery and modeling that integrates interdisciplinary, multiple media, exposure and effects models and databases. Although QMRA does not preclude using source-term and fate and transport models, it is applied most commonly where the source-term is represented by the receptor location (i.e., exposure point), so the full extent of exposure scenarios has not been rigorously modeled. An integrated environmental modeling infrastructure is, therefore, ideally suited to include fate and transport considerations and link the risk assessment paradigm between source and receptor seamlessly. A primary benefit of the source-to-outcome approach is that it allows an expanded view of relevant cause-and-effect relationships, which facilitate consideration of management options related to source terms and their fate and transport pathways. The Framework for Risk Analysis in Multimedia Environmental Systems (FRAMES) provides software technology for analysts to insert appropriate models and databases that fit the problem statement and design and construct QMRAs that are reproducible, flexible, transferable, reusable, and transparent. A sample application using different models and databases registered with FRAMES is presented. It illustrates how models are linked to assess six different manure-based contaminant sources, following three pathogens (Salmonella eterica, Cryptosporidium spp., and E. coli 0157:H7) to a receptor where exposures and health risk impacts are then evaluated. The modeling infrastructure demonstrates how analysts could use the system to discern which pathogens might be important and when, and which sources could contribute to their importance.