Impact of Vegetation-Derived Dissolved Organic Carbon On Disinfection Byproduct Formation During Drinking Water Treatment.

The subalpine forests of the Rocky Mountain Region of Colorado have undergone a significant shift in vegetation population due to the devastating impact of the pine beetle infestation. Subalpine forests in the Colorado Rocky Mountains contain headwater streams that flow to the Front Range providing water for millions of people. This water is typically treated with disinfecting agents such as chlorine during drinking water processing. It is believed the that the dissolved organic matter (DOM) present in the water interacts with the disinfecting agents to form disinfection by-products (DBPs), which are chemicals that pose a threat to human health at certain concentration levels. Different vegetation types release different components of DOM, which could impact the interaction with disinfection agents and ultimately the by-products formed. It is the purpose of this study to study the variability in concentration and type of DBPs produced based on vegetation type. Several whole tree vegetation samples, including pine, spruce, aspen, and fir, were collected from the Fraser Experimental Forest in Fraser, CO. Leachate of each vegetation type was collected over a period of 28 days and total organic carbon and nitrogen was determined to predict the formation of DBPs. The leachate samples were then treated with chlorine to simulate disinfection and promote the formation of by-products. After a 7-day incubation the formed by-products were extracted from solution using EPA method 551.1 and analysis was carried out by gas chromatography electron capture detector. Preliminary results show differences in both concentration and identification of DBPs formed for the distinctive vegetation types over time.