The Investigation of Black Carbon in Freshwater Ecotoxicology — 28p — McKinnely Mull,  Paula Mazzer, Hannah Hamontree, Patrick Hatcher

Black carbon refers to a family of compounds that are produced by the partial combustion of organic material in both natural and man-made fires. Incomplete combustion generates free radicals that vary in reactivity. Depending on the reactivity of each compound new toxicophores are formed. Toxicophores contain specific functional groups capable of forming electrophilic reactive metabolites that are associated with chemical properties. These particles can suspended in the air and inhaled into the lungs. Through the circulatory and respiratory systems black carbon is able to move throughout the body producing systemic reactions. Unlike the aerial suspension of soot, the impacts of BC present in water sources are unknown. The purpose of this research is to characterize the chemical structures and toxicity profiles of chars generated in wildfires to more reliably predict the potential impacts and reactivity of the compounds. Daphnia magna was used as a relevant aquatic species. A portion of the char samples was turned into leachates that were then added in treatment doses to small colonies of Daphnia magna observe the effects. Varying toxicity profiles of the chars were observed depending on the temperature of burn and primary material combusted. Using data generated by Ultra High Resolution Mass Spec, ESI-FITCR- MS, Van Krevelen diagrams were generated. These diagrams allow us to consider possible chemicals in the leachates that could contribute to toxicity. EEMs were generated as complimentary data to understanding the structures of each sample. By comparatively analyzing toxicity assays, Van Krevelen Diagrams, and EEMs we are able to begin clarifying the toxic potential of BC in water runoff. Further analytical investigation is necessary to propose a mechanism of toxicity and scope of impact.

Dakota Wesleyan University
Paula Mazzer