Urban Water Bacterial Source Tracking

Urban waters are subject to numerous pollutant inputs including; combined sewer overflows, sanitary sewer overflows, illicit sewer connections, and stormwater system discharges. These discharges contribute to serious water quality problems, including; human health issues, degraded urban streams, beach closings, shellfish bed closures, and threats to groundwater and drinking water suppliesThe primary goal of this project is the development and application of a practical bacterial source tracking “Stormwater Toolbox” that will generate a multi-layered systematic approach to determine sources of elevated bacterial concentrations. Determining the sources of bacteria in an urban watershed is necessary to implement appropriate pollution-control practices and comply with water quality standards required by the Clean Water Act. A comprehensive sampling and watershed monitoring program was developed to achieve this goal.The objectives of this project were to:develop, test and implement a consistent, logical and cost-effective tiered framework for the application of bacterial source tracking and screening tools;collect data that is usable by EPA enforcement staff for information requests and enforcement actions; andimprove collaboration between watershed organizations and community groups with State and Federal agencies working to improve water quality.Surface water grab samples were retrieved from outfalls or in-stream locations. Analytical parameters included, but were not limited to; bacteria, ammonia, surfactants, potassium, free and total chlorine, total phosphorus, fluoride, and a limited suite of pharmaceutical compounds. These extensive efforts worked to test and compare analytical methods including; laboratory analyses, test kits, and field analysis to determine the most effective and cost-efficient outfall and in-stream sampling approach. Multiple and repeated testing occurred at each location to compare different methods and parameters for identifying possible sewage contamination and pollutant load sources.The data collection phase was conducted from May to September 2009, followed by the evaluation of the different test methods including ranking them by cost, accuracy, and ease of use. Data collected will be used in a “weight of evidence” approach to distinguish between human and non-human sources of bacterial contamination. At the time this manuscript was developed the research effort was halfway through a two year process. All results, discussions and conclusions to follow are preliminary and were summarized for draft release.