ERI: Iodine variability in watersheds and implications for drinking water treatability and public health

Villanova University, Villanova PA

Investigators

Abstract

Over 260 million people in the United States receive drinking water that has been disinfected with chemicals like chlorine. Although chemical disinfection has major public health benefits through the prevention of waterborne disease, it also forms disinfection byproducts (DBPs) through the reaction of bromine (Br), and/or iodine (I) with dissolved organic matter in the water source. These DBPs have been linked to health risks, thus reducing the health gains of disinfection. Relatively little is known about how much Br and I vary in drinking water sources across space and time. Still less is known regarding what concentrations of these compounds result in the formation of DBPs. This proposal will address these gaps in our understanding by assessing how Br and I vary in drinking water sources. Successful completion of this research project will help us better understand drinking water risk resulting from Br and I to create better monitoring and guidelines for improved public health protection. Further benefits to society include strengthening the Nation’s STEM workforce through outreach to K-12 students and educators through watershed decision-making activities. The goal of this proposal is to advance the understanding of how Br and I loading to drinking water sources contribute to downstream drinking water system vulnerability across space and time. DBPs form when natural organic matter in drinking source water reacts with Br and/or I in source waters. While research indicates that Br- and I-containing DBPs are associated with higher cyto- and genotoxicity compared to their chlorinated analogs, the 11 currently regulated DBPs are unlikely to be fully responsible for driving toxicity. There is thus an urgent need for systems-level research on Br and I variability in drinking water sources to understand the potential for DBP formation and control. This research project addresses this need by i) developing geospatial and statistical methods to assess iodine inputs to drinking water sources, and ii) performing targeted source water sampling to assess the spatial and temporal variability of I and Br in affected drinking water sources. In the first objective, Br and I will be assessed in water systems and combined with the National Hydrography Dataset to establish a geospatial flow path model that links upstream discharges to downstream drinking water systems. In the second objective, the results from the transport model will inform targeted monitoring in partnership with a water utility to better understand spatial and temporal variability of Br and I and the effects on finished water Br- and I-DBPs. Successful completion of this project will benefit society by identifying potential vulnerabilities to unregulated DBPs. Results and supporting work will be shared with stakeholders and the scientific community through peer-reviewed journal publications and presentations at scientific conferences, utilities, and regulators through targeted briefings. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.