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BACTERIAL MORTALITY DUE TO SOLAR RADIATION, COMPARING EXPERIMENTAL AND STATISTICAL EVIDENCE

Contact

http://cfpub.epa.gov/si/si_public_comments.cfm

Citation:

FRICK, W. E. AND Z. GE. BACTERIAL MORTALITY DUE TO SOLAR RADIATION, COMPARING EXPERIMENTAL AND STATISTICAL EVIDENCE. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Milwaukee, WI, November 11 - 15, 2007.

Impact/Purpose:

A main objective of this task is to combine empirical and physical mechanisms in a model, known as Visual Beach, that

  • is user-friendly
  • includes point and non-point sources of contamination
  • includes the latest bacterial decay mechanisms
  • incorporates real-time and web-based ambient and atmospheric and aquatic conditions
  • and has a predictive capability of up to three days to help avert potential beach closures.
The suite of predictive capabilities for this software application can enhance the utility of new methodology for analysis of indicator pathogens by identifying times that represent the highest probability of bacterial contamination. Successful use of this model will provide a means to direct timely collection of monitoring samples, strengthening the value of the short turnaround time for sampling. Additionally, in some cases of known point sources of bacteria, such as waste water treatment plant discharges, the model can be applied to help guide operational controls to help prevent resulting beach closures.

Description:

Many researchers report that sunlight is a primary stressor of beach indicator bacteria. Some water quality models include code that quantifies the effect of radiation on bacterial decay. For example, the EPA Visual Plumes model includes two coliform and one enterococcus submodels, including the Mancini (1978) coliform model that expresses bacterial mortality as functions of solar radiation, salinity, and temperature. The Environmental Protection Agency (EPA) has developed and tested a program called Virtual Beach (VB), public-domain software. Among other functions, VB facilitates the development of site-specific multi-variable linear regression (MLR) models. Studies, including those using VB, show that MLR models can produce good estimates, both nowcasts and forecasts, using real-time and forecasted explanatory variables, such as turbidity, cloud cover, wind, and rainfall. In this study we investigate the role solar radiation plays in determining bacterial decay. Based on data published by the U.S. Geological Survey for Huntington Beach (Lake Erie) and other sources, including solar radiation data measured by the Ohio State University's Ohio Agricultural Research and Development Center (OARDC) at their nearby Avon site, we used VB to examine the role of radiation on bacterial decay. This work helps to contrast the influence of solar radiation to other factors affecting the fate of bacteria in beach water.

Record Details:

Record Type:DOCUMENT( PRESENTATION/ ABSTRACT)
Product Published Date:11/12/2007
Record Last Revised:11/19/2007
OMB Category:Other
Record ID: 172525