GEOCHEMICAL ANALYSIS OF FISHING CREEK IN COLUMBIA COUNTY, PA

Fishing Creek Watershed covers 385 square miles over three counties, including the majority of Columbia County, ending at the Susquehanna River. Many watershed residents get their drinking water from the streams, thus there is great interest in their water quality. We analyzed samples from Fishing Creek and some of its tributaries, including Huntington Creek, Stony Brook, and Hemlock Creek. Data on dissolved oxygen, pH, conductivity, and temperature were collected in situ and samples collected at each site. Upon return to the lab, we analyzed samples for turbidity, alkalinity, and acidity, and preserved triplicate subsamples for later analysis of selected cations and anions by ion chromatography and metals by ICP-OES. In general, dissolved species concentrations increased with distance downstream, but not always due to contributions from the tributaries. Stony Brook, for instance, was of very high quality. Our most upstream sampling site, in Stillwater, PA, had a pH near 7 and low concentrations of ions and metals. Our most downstream sample site, in Fishing Creek less than 1.5 miles from its confluence with the Susquehanna River in Rupert, PA, had a pH of 8.5 and higher concentrations of chloride and nitrate (15 and 8 ppm, respectively) than any other samples taken in the main branch of Fishing Creek. This site was just below the confluence with Hemlock Creek, with even higher concentrations of chloride and nitrate (44.6 and 22.5 ppm, respectively). Of the tributaries tested, only Hemlock Creek had a negative impact on the water quality of Fishing Creek, possibly due to the sewage treatment plant just upstream from their confluence. Noted water quality changes above and below the confluence with Hemlock Creek included not just increased chloride and nitrate, but also increased alkalinity and aluminum. Nonetheless, all parameters measured in Fishing Creek itself remained under the limits defined acceptable by the EPA Primary Drinking Water Standards.