Bacterial Source Tracking in Pathogen TMDL Development and Implementation Part II: Challenge and Opportunity

Pathogen contamination is among the leading causes of water quality impairment nationwide. Despite advanced sanitation conditions, contaminated waters continue to cause illness through drinking water use, recreational water use and shellfish harvesting. Knowing the sources of waterborne pathogens in an impaired watershed is of great value in analyzing the potential risk of transmission of infectious diseases and preventing further bacterial contamination. Bacterial Source Tracking (BST) is new methodology that can be used to determine the sources of fecal bacteria (e.g., from humans, wildlife, and livestock) in contaminated waters. There are many BST methods available and more are under development. As part of continuous efforts by EPA in developing Pathogen TMDL guidance, the Office of Water has completed a BST fact sheet, which discusses the utility of BST in TMDL development and implementation, and released “Draft Implementation Guidance for Ambient Water Quality Criteria for Bacteria”. This paper provides latest updates of BST technology in TMDL development and implementation for both inland and coastal waters by their corresponding EPA Region. In summary, utilizing BST in watershed studies provides the advantage of increasing confidence in source identification and the relative distribution of loadings among various fecal sources, thus improving public perception and confidence in successful implementation of watershed management plans.