Monitoring the Formation of Hazardous Oxygenated PAHs in Wildfire-Affected Watersheds

Caption for the picture.

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Reviewed biotransformation pathways were extracted from the EnviPath database for five EPA priority PAHs. Compound Log(KOW), boiling point, and Ames mutagenicity were predicted using ADMETlab 3.0.

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Sediment and water were sampled from Boulder Creek, sieved, and transferred to muffled glassware. “Ash” treatment samples were combined with 500mg/L of crushed and sieved chars, which were formed from wood combusted at 700℃. Bottles were harvested for timepoints samples at 0, 1, and 10 days. DNA extracted from sediment and sequenced for the V4-region of the 16S rRNA gene.

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The stream sample is from the Cache La Poudre River after a high-precipitation rainstorm on 7-21-21. The ash sample is from the Black Hollow Creek subcatchment and was collected by RMRS in December 2020 prior to any measurable precipitation events. Samples were previously filtered and extracted on HLB SPE cartridges before analysis with LC-QToF-MS in negative mode. For further description of processing methods, refer to Thurman, E.M., Ferrer, I., Bowden, M., Mansfeldt, C., Fegel, T.S., Rhoades, C.C., Rosario-Ortiz, F., 2023. Occurrence of Benzene Polycarboxylic Acids in Ash and Streamwater after the Cameron Peak Fire.

Samples were reanalyzed for the masses of predicted PAH derivatives with acidic functional groups.