CHLORIDE, METAL, AND NUTRIENT CONTRIBUTIONS FROM URBANIZED UNIVERSITY CAMPUS WATERWAYS, TOWSON, MD

Urban areas are among the fastest growing land cover types. Although research on the geochemistry and ecology of urban streams is growing rapidly, many basic scientific questions regarding urban stream processes remain unanswered. The streams on Towson University’s campus represent ideal settings for addressing these questions because the numerous streams and the urban nature of the campus afford the opportunity for detailed investigation of the effects of urbanization on stream ecosystems. Additionally, some campus streams have experienced recent restoration, and another is scheduled for restoration in 2017. This project documents seasonal changes in water quality, including metal, salt, and nutrient loading, and an assessment of ecosystem health through benthic macroinvertebrate (BMI) surveys. Preliminary results suggest that the streams on campus are dominated by mixed cation and Cl-dominated waters. Specific conductivity ranges up to 1755 µS/cm. [Cl] can exceed 930 ppm, exceeding both the chronic (230 ppm) and acute (860 ppm) EPA criteria for aquatic life. In comparison, a forested stream draining bedrock with similar chemistry has Na and HCO-dominated chemistry, low specific conductivity (27 µS/cm), and low [Cl] (2.5 ppm). Additionally, [Mn] in some locations exceed the 50ppb EPA secondary maximum contamination levels, and total nitrogen and phosphate concentrations exceeded 3.0 and 0.2 ppm, respectively. Preliminary BMI surveys demonstrate low populations and diversity in the stream slated for restoration. On-campus stream quality is compared to three regional streams in the watershed, Ruxton Run, Roland Run, and Jones Falls, within more rural environments and with fewer impervious surfaces. Specific conductivity in these streams range up to 1271 µS/cm, [Cl] can exceed 364 ppm, exceeding the chronic EPA criteria for aquatic life, [Mn] in few locations exceed the 50ppb EPA secondary maximum contamination levels, and total nitrogen and phosphate concentrations exceeded 3.4 and 1.2 ppm, respectively. Ongoing research will track contributions of salt, nutrients, and metals to campus streams.