Disability-Adjusted Life Year Frameworks for Comparing Health Impacts Associated with <i>Mycobacterium avium</i>, Trihalomethanes, and Haloacetic Acids in a Building Plumbing System

Abstract

To address trade-offs, prioritize, and manage the risks between microbial and chemical risks, the disability-adjusted life year (DALY) approach was utilized. The sampling data from cold and hot water building plumbing in Philadelphia, PA, revealed three classes of health stressors, nontuberculous mycobacteria, total trihalomethanes (THMs), and total haloacetic acids (HAAs). The concentration data specific to the water system were then used to estimate the annual risk due to the Mycobacterium avium complex (MAC), THMs, and HAAs. The results from this study suggest that efforts to reduce the potential health risks from disinfection byproducts should still be given due consideration as the annual DALY of bladder cancer (7.61*10–7) was estimated to be greater than the annual DALY of MAC pulmonary disease (4.74*10–12) by 5 orders of magnitude. The DALYs of both THMs (2.62*10–6) and HAAs (2.60*10–6) in buildings via the ingestion exposure route were higher than the reported threshold of 1 μDALY. Relative to the feed water, water quality changes in the building plumbing substantially increased the DALY impacts for microbial risks but modestly decreased the DALY impacts for chemical risks. While the results are specific to the system considered (e.g., chloramine disinfectant, no detectable Legionella), the study presents a framework for prioritizing among building plumbing microbial and chemical risks.