Source Molecular Presents Human Fecal Score at California Monitoring Group Meeting

Source Molecular Corporation was one of the two invited speakers at the Central/Northern California Ocean and Bay Water Quality Monitoring Group quarterly meeting held early February 2018 in Oakland.

Dr. Yiping Cao, Source Molecular Corporation’s Vice-President of Technology, presented the Human Fecal Contamination Score as a standardized approach for microbial source tracking data interpretation. Various representatives from local health departments, permittees, environmental organizations and the State Water Resources Control Board attended the meeting.

The Central/Northern California Ocean and Bay Water Quality Monitoring Group coordinates the monitoring efforts of state and local agencies and coastal dischargers, and the assessment efforts of regional environmental interests. Traditionally, fecal indicator bacteria are used to monitor the presence of fecal matter in environmental waters. However, the scientific and regulatory communities increasingly regard this method as flawed.

Dr. Cao explains that most people associate FIB to cause diseases but FIB are generally not pathogens. FIB can come from a lot of sources Рhumans, animals, plants, soil and biofilm. Thus, it is difficult to implement mitigation measures without knowing exactly where the bacteria came from.  This is where microbial source tracking (MST) comes in. MST provides a set of methods to identify sources of contamination.

When MST results are on hand, there is still a matter of interpreting the data. Traditionally, MST results are interpreted through a process called best professional judgment (BPJ), which was demonstrated to be highly inconsistent from one professional to another. Such potential for large interpretational bias by BPJ motivated a team of researchers, from USEPA, SCCWRP, and Stanford, to develop a standardized mathematically defined objective approach to MST data interpretation, the human fecal score (HFS). The HFS gives the site average concentration of the HF183 marker. It is a number that characterizes the extent of human fecal pollution at a site. This makes it a simple and intuitive way to assess site condition.

Dr. Cao relates that the HFS takes into account all data – quantifiable, detected but not quantifiable, and non-detect – as all data, even non-detects, contain valuable information. The applications of HFS include measuring BMP effectiveness and site prioritization for mitigation.

Source Molecular’s laboratory, which is ISO/IEC 17025:2005 accredited, performs genetic testing on environmental water samples using host-associated gene markers through quantitative polymerase chain reaction (qPCR). It also provides assistance in the calculation of HFS.

Learn more about how the Human Fecal Score is calculated by simply setting an appointment with Dr. Cao. Source Molecular can also be reached at 786-220-0379 and