Texas continues to be faced with bacteria levels measured in surface water bodies that are above the State’s commonly applied, primary contact recreation standard. According to the 2012 Texas Integrated Report on Surface Water Quality, 48 percent of all impaired waterbodies are impaired due to elevated bacteria levels. Escherichia coli are commonly monitored in freshwaters and are assumed to signify the presence of recent fecal contamination which could also indicate the presence of human pathogens. Recent research has shown that this assumption of E. coli being directly associated with recent fecal contamination may not be appropriate. E. coli indigenous to the soil have recently been confirmed and bacterial source tracking often documents ‘unidentified’ sources of E. coli contributions.
The overall purpose of the Bacteria Fate and Transport Program is to evaluate the behavior of E. coli in the environment (landscape or waterbodies) in an effort to learn more about this indicator bacteria species. Ultimately, knowledge gained can be used to improve management and planning to reduce instream E. coli levels as well as inform policy makers on the appropriate use E. coli in the state’s water quality standards.
Specific goals of current program activity include:
- Assessing the influences of water chemistry on instream E. coli growth and persistence
- Evaluating the sources of ‘background’ E. coli on varying land use/land cover (LU/LC) types containing little or no anthropogenically derived E. coli loading
- Support the development of future TMDLs and WPPs by providing critical information needed for improving the accuracy of computer based models to predict bacteria deposition rate estimates; die-off, growth, and persistence of E. coli; and appropriate background E. coli concentrations across multiple LU/LC types