Effort to model health risks to Inner Cabrillo beachgoers wraps up

SCCWRP and its partners have completed a three-year effort to identify the sources of persistent fecal contamination at Inner Cabrillo Beach in Los Angeles County and to model health risks for beachgoers.

The study, described in a SCCWRP technical report published in April, attempted to use a health risk modeling approach known as Quantitative Microbial Risk Assessment (QMRA) to determine the degree of risk posed by exposure to fecal contamination in the beach water. But despite collecting more 4,000 samples over the three-year study and identifying non-human fecal sources, water-quality managers were unable to identify and eliminate Inner Cabrillo’s persistent human fecal signal.

Thus, the QMRA approach could not be used at Inner Cabrillo. QMRA is designed for use at sites where microbial contamination sources are not predominantly human.

Inner Cabrillo is a popular swimming spot in the Los Angeles Harbor area where fecal contamination levels sometimes exceed water-quality targets. More than $20 million has been spent to improve the beach’s water quality, but bacterial concentrations continue to exceed objectives; the beach has a TMDL (total maximum daily load) for fecal bacteria.