July 7, 2021

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Brandon Steets and Jared Ervin Coauthored a Paper on Tracking Fecal Pollution in the Surf Zone in the Frontiers in Microbiology

Brandon Steets, P.E., (California) and Jared Ervin Ph.D., (California) coauthored a paper entitled "Bather Shedding as a Source of Human Fecal Markers to a Recreational Beach" that was published in Frontiers in Microbiology on June 25, 2021.

Dong Li was the lead author, and other coauthors were Laurie Van De Werfhorst, Jill L. S. Murray, Naresh Devarajan, and Patricia A Holden.

Brandon Steets is a Senior Principal Engineer based in California with more than 20 years of experience in National Pollutant Discharge Elimination System and Total Maximum Daily Load regulations, Clean Water Act litigation, water quality modelling, and monitoring, pollutant source investigation, and stormwater control planning and design.

Jared Ervin is a Senior Professional based in California with more than 10 years of experience focused on pollutant source tracking, surface and groundwater quality, advanced forensic tools, and environmental microbiology.

Frontiers in Microbiology publishes peer-reviewed research across the entire spectrum of microbiology. This multidisciplinary open-access journal disseminates and communicates scientific knowledge and impactful discoveries to researchers, academics, clinicians, and the public worldwide.


Microbial source tracking (MST) can identify and locate surf zone fecal indicator bacteria (FIB) sources. However, DNA-based fecal marker results may raise new questions, since FIB and DNA marker sources can differ. Here, during 2 years of summertime (dry season) MST for a Goleta, California recreational beach, low level human-associated DNA-based fecal marker (HF183) was detected in 25 and 14% of surf zone water samples, respectively. Watershed sources were hypothesized because dry weather creek waters had elevated FIB, and runoff-generating rain events mobilized human and dog fecal markers and Salmonella spp. into creeks. However, the dry weather estuary outlet was bermed in the first study year; simultaneously, creek fecal markers and pathogens were lower or similar to surf zone results. Although the berm breached in the second year, surf zone fecal markers stayed low. Watershed sediments, intertidal beach sands, and nearshore sediments were devoid of human- and dog-associated DNA markers. Based on dye tests and groundwater sampling, beach sanitary sewers were not leaking; groundwater was also devoid of HF183. Offshore sources appeared unlikely, since FIB and fecal markers decreased along a spatial gradient from the surf zone toward nearshore and offshore ocean waters. Like other regional beaches, surf zone HF183 corresponded significantly to bather counts, especially in the afternoons when there were more swimmers. The possibility that multiple, permanent sources—in this case a wastewater treatment plant outfall, and bathers routinely using the beach—can explain low chronic HF183 surf zone detections suggests that there are likely HF183 thresholds that are the lowest achievable at popular bathing beaches.

More Information

Learn more about the article: Frontiers | Bather Shedding as a Source of Human Fecal Markers to a Recreational Beach | Microbiology (frontiersin.org)
Learn more about Frontiers in Microbiology: Frontiers in Microbiology
For consultation regarding water and natural resources contact Brandon at This email address is being protected from spambots. You need JavaScript enabled to view it. or Jared at This email address is being protected from spambots. You need JavaScript enabled to view it.
Learn more about Brandon at: https://www.geosyntec.com/people/brandon-steets
Learn more about Jared at: https://www.linkedin.com/in/jared-ervin-b648aa75/