The Effects of Coal Ash on pH and Microbial Respiration in Neuse River Sediments

Abstract

Coal combustion residuals are by-products of energy production resulting from the burning of coal. The coal combustion residuals, or simply coal ash, are then cleaned from the furnaces and added to water to form a thick mixture which reduces the chances of the ash becoming airborne. In the United States, 32% of all the coal combustion residuals are placed into open, water filled containment ponds where the solids settle and the liquid excess is released into a natural water system. The addition of coal ash to river sediments from runoff has the potential to disrupt the river ecosystem by hindering the absorption of nutrients in the lower levels of the food web which could, in turn, cascade to higher levels of the food web. For the present study, I collected sediment samples upriver, downriver, and beside of a coal ash pond in Goldsboro, North Carolina. I then transported the samples to the laboratory and split them into thirty-six labeled respiration chambers. I then measured the changes in microbial respiration and pH over time using a specialized probe. Sediment pH was significantly lower upriver of the coal ash pond and significantly higher beside the coal ash pond. However, there was no significant difference in microbial respiration when comparing the sediment samples from above, beside, and below the coal ash pond. By understanding the effects of coal ash spillage from the electricity industry specifically on soil pH and cellular respiration, we will be able to better learn how it can alter the aquatic ecosystems of rivers and develop a possible solution.