Quantitative Microbial Risk Assessment

Kerry Hamilton

Kerry Hamilton

Title: Using multiple data streams to determine appropriate environmental concentrations of pathogens using quantitative microbial risk assessment 

Abstract: Legionella spp. is a key contributor to the United States waterborne disease burden. Despite potentially widespread exposure, human disease is relatively uncommon, except under circumstances where pathogen concentrations are high, host immunity is low, or exposures to small-diameter aerosols occurs. Water quality guidance values for Legionella are available for building managers but are generally not based on technical criteria. To address this gap, a quantitative microbial risk assessment (QMRA) was conducted using target risk values in order to calculate corresponding critical concentrations on a per-fixture and aggregate (multiple fixture exposure) basis. Showers were the driving indoor exposure risk compared to sinks and toilets. Based on aggregate fixture exposures, critical concentrations depended on the dose response model (infection vs. clinical severity infection, CSI), risk target used (infection risk vs. disability adjusted life years on a per-exposure or annual basis), and fixture type (conventional vs. water efficient or “green”). 
Bio: Dr. Kerry Hamilton is an Assistant Professor with a joint appointment in the School for Sustainable Engineering and the Built Environment and the Biodesign Institute Center for Environmental Health Engineering. She received her doctoral degree in Environmental Engineering from Drexel University in 2016 and Master's degree in public health from Johns Hopkins University in 2009. She was a Fulbright Scholar to Australia in 2015 and Public Health Fellow at the US Environmental Protection Agency from 2009-2011.