Orr, Alexandra, Department of Ecosystem Science and Management, Penn State University, 222 Forest Resources Building, University Park, PA 16802, aso124@psu.edu; Boyer, Elizabeth, Department of Ecosystem Science and Management, The Pennsylvania State University, 304 Forest Resources Building, University Park, PA 16802, ewb100@psu.edu.
Increasing salinity in surface and groundwaters has become an emerging problem for ecosystem health. The critical zone, which spans from bedrock to treetop, plays a key role in regulating water chemistry through interactions in the atmosphere, lithosphere, and hydrosphere. Anthropogenic inputs, primarily from road salt and wastewater effluent, are a key source of chlorides and salinity, which are key contributors to conductivity. This study explores the sources and variability of chloride, sodium and conductivity in a mixed land-use, karstic watershed of central Pennsylvania. We analyzed annual and seasonal concentrations of these parameters in streams and springs across urban, agricultural, forested, and mixed-land use sub-basins. Initial results have indicated increasing chloride and sodiumconcentrations in both surface and groundwaters in urban and mixed land-use locations. Continuous conductivity data from selected locations, including periods of baseflow and storm events, indicates a more complex story where conductivity may be diluted or enriched based upon the season. The results of this study can form the basis for identification of stream reaches that may experience chronic or acute chloride pollution concentrations, which can inform watershed management strategies, including road salt application, stormwater management, and restoration efforts to mitigate water quality degradation.