Source Molecular Corporation was one of the presenters at the recent stormwater seminar organized by the Chesapeake Water Environment Association with the theme, “Beyond Nutrients: Case Studies and Tools for Addressing TMDLs.”-endpar-
Mauricio Larenas, Source Molecular’s chief operating officer, gave a talk on “Evidence-based Guidelines for Microbial Source Tracking Projects” at the seminar held June 8, 2016, at the Maritime Institute of Technology and Graduate Studies (MITAGS) in Linthicum Heights, Maryland.
Mr. Larenas gave water quality professionals who attended an idea of how microbial source tracking (MST) can be used to address fecal bacteria problems in their watersheds. As examples, Mr. Larenas cited the work that Source Molecular did on the Delaware Department of Natural Resources and Environmental Control (DNREC) Beach Source Tracking Project, Arroyo Burro Beach Source Tracking Project, San Juan Basin Bacteria Source Tracking Project, and San Diego River MS4 Project.
In the DNREC Beach Source Tracking Project, MST analysis showed that the major culprit of the fecal bacteria in the beaches were gulls while human fecal indicators were in low levels. This allowed the government agency to create best management practices (BMPs) targeted to reduce pollution from birds such as educating the public about feeding the birds and putting up better trash receptacles.
In Santa Barbara, California, portions of the Arroyo Burro watershed were plagued with high levels of fecal bacteria and officials were looking at multiple potential sources. An MST study narrowed down the sources to Dog, Gull and Humans and it also identified which source was prevalent in specific locations. Gull fecal bacteria, for example, was confirmed at the lagoon and beach.
In the San Juan Basin Bacteria Source Tracking Project, both human and non-human sources ranked high as major contaminants. Based on 2013 and 2014 sampling results, 77% of the samples tested positive for human fecal indicators and 94% of the samples tested positive for ruminant fecal indicators. Targeted public outreach campaigns were launched to address these pollution sources.
In the San Diego River MS4 Project, high fecal bacteria counts were detected at MS4 outfalls. Officials thought it might be caused by illicit connections, leaking sewer pipes and homeless encampments. The MST study showed that there was no need to spend millions of dollars to fix the sewage system because there was no evidence of illicit connections and sewer leaks. Homeless encampments near the MS4 outfalls were the cause of the human fecal pollution in the water.