USGS Water Resources Institute Program
02/01/2020 – 01/31/2022
Earlier studies in Hawai‘i demonstrated that soil can be a source of pathogen indicators (enterococci and Escherichia coli), hence in some situations these bacteria may not be indicative of health risk, nor do these bacteria discriminate between contamination sources (soil, sewage, animal waste). The overarching goal of this project is to improve surface water monitoring programs in American Samoa by validating methods capable of discriminating between contamination sources and investigating the health risk association of pathogen indicators in selected watersheds on Tutuila Island. To achieve this goal, we will (1) determine pathogen indicator (enterococci and E. coli) and alternative pathogen indicator (C. perfringens) concentrations in the soil; (2) conduct laboratory experiments to determine if pathogen indicators can grow in the soil; (3) determine specificity and sensitivity of two human, one dog, and one pig associated test based on animal and sewage samples collected; and (4) investigate the health-risk relationship of pathogen indicators and reference pathogens by analyzing water samples from five watersheds, as well as source-specific tests. This project will enable meaningful science-based surface water management strategies and formulation of protective site-specific water quality standards. This project is a collaborative effort between the AS-EPA, ASPA, ASCC, HI Sea Grant, and WRRC.