The impacts of pH on trace contaminant leaching and toxicity of coal ash in Planorbella duryi

by Catherine Crowell

Faculty mentor: Dr. Tyler Frankel

Coal fly ash is a major industrial waste that is primarily produced by coal-burning power plants. Ash contains multiple trace contaminants that have the potential to leach into waterways after rain events, causing undesirable effects on aquatic species in these ecosystems. Few laboratory studies have examined the relationship between acidified rainfall and the release of trace metals from coal ash and the impacts of such rainfall on the toxicity of coal ash leachates on aquatic invertebrates. Thus, the goals of this study were to 1) evaluate the effect of varying pH’s on the leaching of trace contaminants from coal ash and 2) examine the impacts of these leachates on the viability, development, and hatch rate of embryonic Planorbella duryi, a freshwater snail species found in intermittent streams throughout North America. Briefly, 100g of coal fly ash obtained from a local coal ash repository was added to individual glass vessels containing 1L of synthetic water adjusted to pH’s of 4.5 to 7.5. After 48 hours, all leachates were vacuum filtered and an aliquot analyzed for aluminum, arsenic, calcium, cadmium, chromium, cobalt, iron, mercury, magnesium, manganese, lead, selenium, and zinc using ICP-OES. Embryonic P. duryi clusters (<2hrs old) were then exposed to each leachate for 10 days using a 48hr static-replacement assay, and the number of viable individuals and hatchlings in each cluster assessed daily. To examine the impacts on growth, photographs of each embryo were obtained every 24 hours. While this project is currently ongoing, we expect to find increases in aqueous trace contaminant concentrations as a result of decreased pH in leachates as well as decreased viability, growth, and hatching success. This study will provide important information regarding the potential impacts of acidified rainfall on the mobilization of trace contaminants and toxicity of coal ash leachates on aquatic invertebrates.

4 Replies to “The impacts of pH on trace contaminant leaching and toxicity of coal ash in Planorbella duryi”

  1. Hi Katie,
    Very exciting project – and you did an excellent job! Not sure if you’re graduating? I don’t think so … so I look forward to seeing you next year!

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