July 13, 2022

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Brandon Steets and Jared Ervin Coauthored a Paper on Human Sources of Bacteria in Surf Zone Waters in the journal Water Research

Brandon Steets, P.E., and Jared Ervin, Ph.D., (California) coauthored a paper titled "Assessing multiple fecal sources to surf zone waters of two recreational beaches by bacterial community analysis" published in journal Water Research on August 1, 2022.

Dong Li was the article's lead author. Brandon and Jared's other coauthors were Laurie C. Van De Werfhorst, and Patricia A. Holden, and Jen Smith of University of California, Santa Barbara and Jill L.S. Murray of the Santa Barbara Department of Parks and Recreation.

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, water quality modeling and monitoring, pollutant source investigation, and stormwater best management practices planning and design. He is a subject matter expert on bacteria and pathogens and is a member of California State Water Resources Control Board Clean Beaches Task Force.

Jared Ervin is a Senior Professional based in California with more than 16 years of experience focused on pollutant source tracking, surface and groundwater quality, advanced forensic tools, and environmental microbiology. Jared leads water quality and pollutant source tracking investigations in California and across the country and has extensive experience designing studies; managing sampling and laboratory analyses; and interpreting data to develop ways to improve water quality and comply with permits.

Water Research publishes refereed, original research papers on all aspects of the science and technology of the anthropogenic water cycle, water quality, and its management worldwide. The journal has been reporting outcomes from the forefront of science and engineering and research for more than 50 years.


Fecal sources to recreational surf zone waters should be identified to protect public health. While watershed origins of human and other fecal sources are often discoverable by quantitative polymerase chain reaction (qPCR) of fecal markers using spatially stratified samples, similarly assessing wastewater treatment plant (WWTP) outfall and other offshore contributions to surf zones is challenged by individual marker fate and transport. Here, bacterial communities were assessed for relatedness between all hypothesized fecal sources and surf zone waters for two urban California recreational beaches, by sequencing genes encoding 16S rRNA and analyzing data using SourceTracker and FEAST. Ambient marine bacterial communities dominated the surf zone, while fecal (human, dog, or gull) or wastewater (sewage or treated WWTP effluent) bacterial communities were present at low proportions and those from recycled water were absent. Based on the relative abundances of bacterial genera specifically associated with human feces, the abundances of HF183 in bacterial community sequences, and FEAST and SourceTracker results when benchmarked to HF183, the major sources of HF183 to surf zone waters were human feces and treated WWTP effluent. While surf zone sequence proportions from human sources (feces, sewage and treated WWTP effluent) appeared uncorrelated to previously obtained qPCR HF183 results, the proportions of human fecal and potential human pathogen sequences in surf zone waters were elevated when there were more swimmers (i.e. during weekday afternoons, holidays and busy weekends, and race events), thus confirming previously-published qPCR-based conclusions that bather shedding contributed low levels of human fecal contamination. Here, bacterial community sequencing also showed evidence that treated WWTP effluent from an offshore outfall was entering the surf zone, thereby resolving a prior uncertainty. Thus, bacterial community sequencing not only confirms qPCR HF183-based human marker detections, but further allows for confirming fecal sources for which individual marker quantification results can be equivocal.

More Information

Learn more about the article: Assessing Multiple Fecal Sources by Bacterial Community Analysis
Learn more about Water Research | Journal | ScienceDirect.com by Elsevier.
For consultation regarding water quality and water contamination contact Brandon Steets at This email address is being protected from spambots. You need JavaScript enabled to view it..
Learn more about Brandon Steets at: https://www.geosyntec.com/people/brandon-steets
Learn more about Jared Ervin at: https://www.linkedin.com/in/jared-ervin-b648aa75/