Evaluating phytochemical and microbial contributions to atrazine degradation

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dc.contributor.authorHatch, K. M.en
dc.contributor.authorLerch, R. N.en
dc.contributor.authorKremer, R. J.en
dc.contributor.authorWillett, C. D.en
dc.contributor.authorRoberts, C. A.en
dc.contributor.authorGoyne, Keith W.en
dc.date.accessioned2023-05-24T14:57:19Zen
dc.date.available2023-05-24T14:57:19Zen
dc.date.issued2022-11en
dc.description.abstractThe inclusion of warm-season grasses, such as switchgrass (Panicum virgatum) and eastern gamagrass (EG) (Tripsacum dactyloides), in vegetated buffer strips has been shown to mitigate herbicide contamination in runoff and increase herbicide degradation in soil. The mode of action by which buffer strip rhizospheres enhance herbicide degradation remains unclear, but microorganisms and phytochemicals are believed to facilitate degradation processes. The objectives of this study were to: 1) screen root extracts from seven switchgrass cultivars for the ability to degrade the herbicide atrazine (ATZ) in solution; 2) determine sorption coefficients (Kd) of the ATZ-degrading phytochemical 2-beta-D-glucopyranosyloxy-4-hydroxy-1,4-benzoxazin-3-one (DBG) to soil and Ca-montmorillonite, and investigate if DBG or ATZ sorption alters degradation processes; and 3) quantify ATZ degradation rates and soil microbial response to ATZ application in mesocosms containing soil and select warm-season grasses. Phytochemicals extracted from the roots of switchgrass cultivars degraded 44-85% of ATZ in 16-h laboratory assays, demonstrating that some switchgrass cultivars could rapidly degrade ATZ under laboratory conditions. However, attempts to isolate ATZ-degrading phytochemicals from plant roots were un-successful. Sorption studies revealed that DBG was strongly sorbed to soil (Kd = 87.2 L kg-1) and Ca-montmorillonite (Kd = 31.7 L kg � 1), and DBG driven hydrolysis of ATZ was entirely inhibited when either ATZ or DBG were sorbed to Ca-montmorillonite. Atrazine degradation rates in mesocosm soils were rapid (t0.5 = 8.2-11.2 d), but not significantly different between soils collected from the two switchgrass cultivar mesocosms, the eastern gamagrass cultivar mesocosm, and the unvegetated mesocosm (control). Significant changes in three phospholipid fatty acid biomarkers were observed among the treatments. These changes indicated that different ATZ-degrading microbial consortia resulted in equivalent ATZ degradation rates between treatments. Results demonstrated that soil microbial response was the dominant mechanism controlling ATZ degradation in the soil studied, rather than root phytochemicals.en
dc.description.adminPublic domain – authored by a U.S. government employeeen
dc.description.versionPublished versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.1016/j.jenvman.2022.115840en
dc.identifier.eissn1095-8630en
dc.identifier.issn0301-4797en
dc.identifier.pmid35994960en
dc.identifier.urihttp://hdl.handle.net/10919/115173en
dc.identifier.volume321en
dc.language.isoenen
dc.publisherAcademic Pressen
dc.rightsPublic Domain (U.S.)en
dc.rights.urihttp://creativecommons.org/publicdomain/mark/1.0/en
dc.subjectAtrazineen
dc.subjectDegradationen
dc.subjectPhytochemicalsen
dc.subjectVegetated buffer stripsen
dc.subjectBenzoxazinoneen
dc.subjectSorptionen
dc.titleEvaluating phytochemical and microbial contributions to atrazine degradationen
dc.title.serialJournal of Environmental Managementen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten

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