Utilization of microbial source-tracking markers to inform targeted remediation

Although Escherichia coli and enterococci will be recommended for use as recreational water quality standards (RWQS) for all surface waters by the U.S. EPA, measuring their levels contributes little to our knowledge of the source of contamination in nonpoint source (NPS) impacted waters. Yet understanding the sources of fecal pollution is critical for developing management plans to protect recreational waters and for assessing the associated health risks. Testing for these fecal indicator bacteria (FIB) augmented with microbial source-tracking (MST) assays may improve our ability to identify and prioritize sources that have a high likelihood of contributing human pathogens to surface waters. Yet more research is required to understand how MST methods relate to measurements of FIB in inland waters, which are predominantly impacted by NPS containing both human and animal source fecal contamination. To understand whether MST assays can aid in better targeting of remediation efforts, novel, promising MST markers were evaluated for (1) their relationship to land use, (2) their ability to predict microorganisms of public health concern, and (3) their association with FIB within two areas of the Cape Fear watershed. The results of this research suggest that MST markers are necessary for identifying and prioritizing areas with a high likelihood of contributing human pathogens to surface waters, but that they cannot be easily utilized in a tiered approach with FIB.

Utilization of microbial source-tracking markers to inform targeted remediation and predict potential pathogens in high priority surface waters. J. G. Shields. 2012. The University of North Carolina, Chapel Hill, NC, USA. doi.org/10.17615/jve6-yq47