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Paper No. 62-2
Presentation Time: 8:00 AM-12:00 PM
A GEOCHEMICAL ANALYSIS OF RESIDENTIAL WATER WELLS IN COLUMBIA COUNTY, PA
Many residents near Bloomsburg, PA, rely on wells for their water. Water quality can be quite variable depending on the geologic formation from which the water is being produced. We went to five single family residences, 4 clustered in Scott Township and 1 about 5 miles away in Montour Township. Of the Scott Township wells, 3 were located on surface rocks of the Bloomsburg/Mifflintown Formation and the fourth on rocks of the Wills Creek Formation. The Montour Township well is drilled through the Onondaga and Old Port Formations. Due to the geologic structure (an anticline,) the formations at the surface are not necessarily the rocks of each well’s aquifer, dependent on well depth, which was not known for most of the wells tested. Our goal was to analyze well water quality to determine the formations from which the wells were producing. If a treatment system was installed at the residence, we sampled both before and after the treatment system (if possible). We conducted in situ measurements of dissolved oxygen, pH, conductivity, and temperature. Samples were collected and taken back to the lab for analysis of alkalinity, acidity, and turbidity. Triplicate sub-samples for anions, cations, and metals were preserved and later analyzed. Water quality in all cases was within potable limits (at least after treatment), much to the relief of faculty well owners. The only species of concern was nitrate, which was high (16.5-18 ppm) in all but one well, unlike what we found in a similar study involving some of the wells in 2012. We are investigating possible causes of the high nitrate: leaky abandoned septic systems in Scott Township which recently went to a public sewer system; effects of a upslope horse farm and adjacent agricultural field in the Montour Township well. Chemical analyses from wells in specific rock formations can be highly variable (Williams 1987), making determination of the producing rock formation based solely on the geochemistry of the water difficult.