Browsing by Author "Hayes, Erin"

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    ASSESSING THE POTENTIAL OF DISINFECTION BYPRODUCTS IN DRINKING WATER FROM GROUNDWATER IN NORTH CAROLINA AQUIFERS
    (2016-04-29) Harvey, Cassandra; Hayes, Erin
    Over 4 million people in North Carolina rely on coastal groundwater aquifers as a source of drinking water. Utilities disinfect this water primarily with chlorine in order to remove pathogens, but the process can result in the formation of disinfection byproducts (DBPs), some of which are classified as potential carcinogens. Halide ions (chloride, bromide, and iodide), have been discovered to be precursors of disinfection byproducts (DBPs), however only chloride is regulated by the EPA with a maximum contaminant level (MCL) of 250 mg/L in drinking water. Even though most public utilities meet this standard, many still see an elevated levels of DBPs, implying that other factors may be influencing their formation. Studies have shown that bromide and iodide, although typically found in significantly lower concentrations, have the chemical potential to produce a higher amount of more toxic DBPs than what is currently being regulated. Total organic carbon (TOC) is another known precursor. Coastal aquifers can have a distinct geochemistry based on their geologic history and hydrogeology. Proximity to seawater can also affect the geochemical makeup of these aquifers, all of which can lead to changes in halide concentrations. Our research characterizes the geochemistry of several aquifers near the coast of North Carolina and examines a broad spectrum of DBP precursors to correlate with DBP formation. Samples were collected from nine public utilities along the Coastal Plain, with each utility using chlorination for disinfection and reporting elevated TTHMs. We analyzed these for halide ion and TOC concentrations along with concentrations of several regulated and unregulated DBPs, determined via disinfection simulation. Through a geospatial analysis of the collected samples we can characterize the spatial variability in chemical concentrations within aquifers across the coastal plain. By identifying and understanding the factors in DBP formation we can better identify the causes of elevated DBP occurrence throughout the North Carolina Coastal Plain and use these results as a tool for predicting DBP formation in other coastal communities.