This research regards assessing human fecal pollution in coastal watersheds and waters, including studying origins and fates. Where coastal waters are contaminated by pathogen-containing fecal material, public health is threatened. Conventional indicators of fecal contamination do not specifically reveal human fecal sources. Estuaries and wetlands may attenuate pathogens and other pollutants that are transported towards the coastal ocean via dry weather flow and stormwater runoff. Biotic markers of human waste are subject to decay, as well as accumulation or growth, but the patterns may differ from those observed for pathogens. Our research is towards understanding human fecal contamination in coastal urban settings, and the implications for human health in a systems context. Methods include comparatively quantifying conventional waste indicators, quantitative PCR-based markers specific to human waste, abundances of select pathogens, and sewage-related chemical indicators. Mathematical modeling is used to interpret results of quantitative sample analysis relative to the physical system. Culture-independent techniques in whole community analysis are also of interest, to the degree that patterns of human fecal contamination can be discerned from indigenous microbial communities.
This work was originally funded by the UC Toxic Substances Research and Teaching Program, and by the USGS. A long-term collaboration has been with the City of Santa Barbara, Creeks Division, which provides context and access to urban creek systems in researching origins of human fecal pollution in coastal cities. Funded (to the City Creeks Division) by Proposition 50 in the State of California Clean Beaches Initiative, the work with Dr. Jill Murray of the City Creeks Division culminated in a user-friendly guide for tracking human fecal pollution in urban drains, creeks, and at beaches (cover image, right), available on the City of Santa Barbara website (https://www.santabarbaraca.gov/civicax/filebank/blobdload.aspx?BlobID=16722). From 2015-19, research during dry weather (AB411 period of April through October) was supported by the Clean Beaches Initiative (CBI) in the State of California, building from the Source Identification Protocol Project (SIPP) that delivered a manual for Microbial Source Tracking for the State of California (https://www.waterboards.ca.gov/water_issues/programs/beaches/cbi_projects/docs/sipp_manual.pdf). The study during dry weather, when upstream catchments are hydrologically disconnected from surf zones, has regarded determining sources of low levels of human fecal pollution at beaches. Starting in the winter of 2018, CBI funding was partially directed by permission of the State to support additional research at Goleta Beach, where sediments cleared from the 2018 Montecito Debris Flow were disposed.