THE EFFECTS OF IMPROVED AIR QUALITY ON A SHALLOW GROUNDWATER SYSTEM

Water quality in the Conemaugh River watershed is continuously monitored by the Environmental Protection Agency (EPA). Additionally, the EPA conducted acid rain studies specifically looking at SO₂ concentrations in a larger region that includes the Conemaugh watershed. One specific region (south of Ebensburg, PA) was included in a round of water quality tests in 1994. This region has very little agricultural run-off and no known coal mining. Population impact is minimal due to the rugged terrain and controlled development. The results from the 1994 tests showed the groundwater to be mildly acidic with above normal sulfate, aluminum, and iron levels. Our project was to evaluate the present water quality at the same locations in the Ebensburg region to determine if the water chemistry has changed over the past sixteen years. The most recent samples had lowered metal and sulfate concentrations and pH readings rose to mildly basic. We believe this improvement is due to the implementation of air quality improvement projects on coal-burning power plants. The EPA’s acid rain study determined positive results with a 52% reduction of acid rain (primarily as SO₂ emissions) levels. With reduced atmospheric deposition of SO₂, aluminum leaching from the surrounding rock would decrease. Since ferrous iron (Fe⁺²) dissolves into mildly acidic groundwater, reducing the amount of acid introduced into the water results in increased pH levels. This mildly basic water now limits the iron dissolution. As the pH levels rise, sulfate is also reduced due to the oxidation of hydrogen sulfide. While further studies need to be conducted over a larger area of this watershed, our results indicate that air quality improvements have positive effects on surface water and shallow groundwater systems.