Summer sampling completed to support health risk modeling study

SCCWRP and its partners have completed an initial round of sampling at Inner Cabrillo Beach for a study that aims to ascertain whether high fecal indicator levels at the Los Angeles County beach are indicative of a health threat to beachgoers who enter the water.

Data from the summer sampling effort will enable the study’s advisory committee to determine if and how to move forward with using a health risk model known as Quantitative Microbial Risk Assessment (QMRA) to quantify the risk of gastrointestinal illness for Inner Cabrillo beachgoers.

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

This summer’s sampling effort was focused on determining whether the bacterial contamination at Inner Cabrillo is from human vs. non-human sources, such as birds. Human sources of contamination are much more likely to contain the pathogens that make people sick.

QMRA is designed for use in places where the contamination sources are not human, according to 2012 guidelines issued by the U.S. Environmental Protection Agency. To date, a QMRA has not been conducted in California, nor at any U.S. marine beach.

The advisory committee will meet in November to interpret the Inner Cabrillo data.