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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Zachary R. Laughrey</dc:contributor>
  <dc:contributor>Amanda L. Stickney</dc:contributor>
  <dc:contributor>Keith A. Loftin</dc:contributor>
  <dc:contributor>Natalie M. Hull</dc:contributor>
  <dc:creator>Zanna J. Leciejewski</dc:creator>
  <dc:date>2025</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Microcystin-LR (MC-LR), a toxin produced during some cyanobacterial harmful algal blooms (cyanoHABs), can harm ecosystems and require consideration in water treatment. Ultraviolet (UV)-C treatment has the potential to degrade cyanotoxins with less harmful byproducts than other treatments. This study compares MC-LR degradation in three different water types using UV-C light emitted from a krypton-chlorine excimer lamp (UV light at 222 nm, UV&lt;/span&gt;&lt;sub&gt;222&lt;/sub&gt;&lt;span&gt;) or a low-pressure (LP) Hg lamp (UV light at 254 nm, UV&lt;/span&gt;&lt;sub&gt;254&lt;/sub&gt;&lt;span&gt;). Quantitative analyses by enzyme-linked immunosorbent assay (ELISA), ultra-performance liquid chromatography with photodiode array detection (UPLC-PDA), and high-performance liquid chromatography-high-resolution mass spectrometry (LC-HRMS) demonstrated that UV&lt;/span&gt;&lt;sub&gt;222&lt;/sub&gt;&lt;span&gt;&amp;nbsp;had a degradation rate constant 2.4–4.2 times greater than UV&lt;/span&gt;&lt;sub&gt;254&lt;/sub&gt;&lt;span&gt;. This aligns with the MC-LR molar absorption (ε) and quantum yield (Φ) in deionized (DI) water. LC-HRMS revealed the photoisomer concentration increasing with UV dose. Trends of abundant photoisomers indicate further degradation. Together, these trends indicate UV&lt;/span&gt;&lt;sub&gt;222&lt;/sub&gt;&lt;span&gt;&amp;nbsp;is a more complete pathway toward protein phosphatase inhibition 2A (PP2A) inactive compounds than UV&lt;/span&gt;&lt;sub&gt;254&lt;/sub&gt;&lt;span&gt;. Electrical energy per order (&lt;/span&gt;&lt;i&gt;E&lt;/i&gt;&lt;sub&gt;EO&lt;/sub&gt;&lt;span&gt;) for UV&lt;/span&gt;&lt;sub&gt;222&lt;/sub&gt;&lt;span&gt;&amp;nbsp;and UV&lt;/span&gt;&lt;sub&gt;254&lt;/sub&gt;&lt;span&gt;&amp;nbsp;was similar across all water matrices and analytical methods, demonstrating that UV&lt;/span&gt;&lt;sub&gt;222&lt;/sub&gt;&lt;span&gt;&amp;nbsp;has the potential to surpass the degradation and electrical efficiency of UV&lt;/span&gt;&lt;sub&gt;254&lt;/sub&gt;&lt;span&gt;&amp;nbsp;used in water disinfection.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1021/acs.est.5c03660</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>American Chemical Society</dc:publisher>
  <dc:title>Comparison of Microcystin-LR degradation by UV222 and UV254</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>