Bacterial Source Tracking in Pathogen TMDL Development and Implementation

Fecal coliform is among the top causes of water quality impairment nationwide, according to the Clean Water Act section 303(d) report. Various sources contribute pathogens to contaminated waters. However, it can be difficult to address water quality impairment effectively without a reliable method to determine the source of contamination. Bacterial Source Tracking (BST) is a new methodology that can be used to determine the sources of fecal bacteria (e.g., from humans, wildlife, and livestock). As part of continuous efforts by EPA in developing TMDL documents and guidance, EPA's Office of Wastewater Management has recently completed a BST fact sheet, which discusses the utility of BST in TMDL development and implementation. This paper emphasizes the applications of BST technology in TMDL development and implementation for both inland and coastal waters. Since little research comparing individual methods is complete because BST development is so new, this paper also discusses several ongoing BST comparison studies. This review shows that results of BST analysis, combined with the output of simulation models, could give considerable scientific justification to TMDL allocation scenarios and implementation plans for waterbodies contaminated by fecal bacteria.