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Title:Contributions of photochemically-produced reactive intermediates to contaminant photodegradation in natural surface waters
Author(s):Risch, Alyssa
emerging contaminants
Abstract:Presented by: Alyssa Risch – Undergraduate research assistant at University of St. Thomas, Co-authors: Kailey E. Beer, Isabella M. Kelly, Stephanie M. Berg, Christina K. Remucal, Kristine H. Wammer Abstract: Some chemical contaminants in natural waters can undergo direct photodegradation when they absorb photons from sunlight. Some contaminants can also undergo indirect photodegradation when dissolved organic matter (DOM) in surface waters absorb photons and become excited, resulting in formation of photochemically-produced reactive intermediates (PPRI). These PPRIs, such as triplet state DOM (3DOM*), singlet oxygen (1O2), and radical species including the hydroxyl radical (∙OH), may then react with and degrade the contaminant. In order to determine which of these PPRIs contribute most to degradation of selected pharmaceuticals in various surface waters, quenchers were used in photolysis experiments. Water samples were spiked with a contaminant (sulfadiazine, carbamazepine, or atorvastatin) and a quencher: 1,4-diazabicyclo[2.2.2]octane (DABCO; 1O2 quencher), sorbic acid (3DOM* quencher), or isopropanol (radical quencher). Samples were then photolyzed (365 nm bulbs) and degradation rates determined. The decrease in rate constants observed with the addition of DABCO and sorbic acid indicates that 3DOM* and 1O2 contribute to the degradation of all three contaminants, with a less pronounced effect on atorvastatin than sulfadiazine or carbamazepine. ∙OH may also contribute to carbamazepine’s degradation. Biography: Alyssa is a senior biochemistry major at the University of St. Thomas. She is also minoring in sustainability, English, and mathematics. After graduating in May, she hopes to start a career in the environmental science field, such as water quality monitoring.
Issue Date:2021-04-27
Series/Report:2021 Emerging Contaminants in the Environment Conference (ECEC21)
Genre:Presentation / Lecture / Speech
Conference Paper / Presentation
Date Available in IDEALS:2021-04-26

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