Our graduate student, Shannon Edmonds, is having her exit seminar today at 4:00 pm in ANSC 0408.
Investigating the Effects of Coal Ash Storage Facilities on Aquatic Biota
Shannon Edmonds, Dr. Lance Yonkos (Advisor)
Abstract:
In 2015 the United States produced 117.3 million tons of coal combustion waste (CCW), or coal ash (American Coal Ash Association 2016). A 2010 report estimated that 300 landfills and 584 storage ponds exist throughout the United States (Zierold and Sears 2014). These facilities vary in their size and construction, and can be unlined, clay-lined, or composite lined. Unlined landfills can cause runoff and seepage of coal ash related contaminants.
This project investigates the toxicological consequences of leachate from “dry” coal ash disposal on water quality and biota in receiving waters. The study includes laboratory-based toxicity testing of field-collected media. A quarterly series of whole effluent toxicity tests was completed on discharge samples from three Maryland disposal facilities. Results indicate varying levels of chronic toxicity at all three locations. Priority metals and major ions have been measured and monitored over time and concurrently with the bioassays. The wastewaters were found to be consistently high in total dissolved solids (TDS) and high conductivities were consistently observed, both indicative of elevated major ions.
Traditional phase 1 toxicity identification evaluation (TIE) methods are not effective at addressing major ion toxicity (Goodfellow et al. 2000, Norberg-King et al. 2005). Therefore, the purpose of the present study is to evaluate the toxicity associated with major ion imbalances using mock effluents and a weight-of-evidence approach in order to determine and confirm the primary causative ions. Calcium, chloride, magnesium, sodium, potassium, and sulfate were used to create a reconstituted mock effluent. A 7-day static renewal dilution series was completed using Ceriodaphnia dubia and threshold inhibition concentration values were compared between the reconstituted mock effluent and the wastewater. Historic effluent data was compared with current effluent data across the three sites and seasonal patterns were observed and noted.