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Coastkeeper and Source Molecular Launch Partnership to Pinpoint Sources of Local Water Pollution

  • DNA-based technology identifies sources of bacteria in local waters
  • Coastkeeper and Source Molecular to test waters throughout Santa Ana River watershed

ORANGE COUNTY – Orange County Coastkeeper and Source Molecular Corporation announce a new partnership to investigate sources of pollution in the Santa Ana River Watershed. With this partnership, Coastkeeper’s water quality testing now uses more ef-fective tools to find sources of pollution and improve human health from the Inland Empire to Orange County.

In early 2018, Coastkeeper observed high levels of fecal bacteria counts at multiple areas of the Santa Ana River Watershed – four sites in Orange County and three in the Inland Empire. When its initial tests detected the presence of fecal indicator bacteria such as E. coli and Enterococ-cus, it sent water samples to Source Molecular for further analysis.

“Fecal bacteria in our waters is an indicator of threats to human health,” says Ray Heimstra, Coastkeeper’s associate director of programs. “Thanks to Source Molecular’s DNA-based tech-nology, we have better data to find the sources of contamination in the Santa Ana River water-shed.”

Source Molecular was selected as it is the only accredited laboratory to offer EPA tests which specializes in a DNA-based method to identify bacteria sources – a process known as microbial source tracking or MST. MST is used to identify sources of fecal pollution in water.

The process works by looking for unique genetic markers, found on gut bacteria specifically on the Bacteroides bacteria. All warm-blooded animals have gut bacteria, however bacteria in each host is unique because of differences in their diet and body temperature. Source Molecular can identify up to 13 host sources, including EPA tests for human, cow, dog and chicken sources. These EPA tests have been proven to be 97-100 percent accurate with no to very minimal cross reactivity.

This partnership will support Coastkeeper’s work to test water quality during rain events at eight targeted locations throughout the watershed. After identifying sources of pollution, Coastkeeper uses legal enforcement to improve water quality and help facilities come into compliance with clean water regulations.

“We can only improve our waters when we identify the real culprits of bacterial contamination,” says Source Molecular CEO Mauricio Larenas. “Microbial source tracking is nationally recog-nized as an effective tool to investigate bacterial impairment.”

The U.S. Environmental Protection Agency has a guide document about how MST can support bacteria total maximum daily load (TMDL) development and implementation during the assess-ment process, the allocation analysis, and/or development of an implementation plan.

The Santa Ana River Watershed, which covers 210.47 square miles, is the largest watershed in Orange County with many potential sources of fecal bacteria. Stormwater pollution is consid-ered the number one water quality problem and has impaired many of Orange County’s water-bodies.


Founded in 1999, the mission of Orange County Coastkeeper is to protect and promote sus-tainable water resources that are swimmable, drinkable, and fishable. Coastkeeper is a nonprof-it clean water organization that serves as a proactive steward of our fresh and saltwater ecosys-tems. We work collaboratively with diverse groups in the public and private sectors to achieve healthy, accessible, and sustainable water resources for the region. We implement innovative, effective programs in education, advocacy, restoration, research, enforcement, and conserva-tion. For more information, visit or call 714-850-1965.

Source Molecular, the world’s only ISO-accredited microbial source tracking laboratory, works with consultants and nonprofit organizations across the country. Its results have been used for site prioritization and to demonstrate effectiveness of best management practices. The laborato-ry also offers pathogen detection and digital polymerase chain reaction services to complement and enhance microbial source tracking results. For more information, visit or call (786) 220-0379.