University of California, Riverside

Environmental Sciences

Daniel Schlenk

Daniel Schlenk

Daniel Schlenk Photograph

Department Vice Chair
Professor of Aquatic Ecotoxicology

Academic Degrees:

  • Ph.D. Oregon State University, 1989
  • B.S. Northeast Louisiana University, 1984


  • His research focuses on understanding the biochemical factors that influence susceptibility to environmental and natural chemicals. Four specific projects involve the impact of climate change on environmental factors that influence detoxification strategies in aquatic organisms; mechanistic investigations of the effects of salinity on pesticide toxicity in fish; the role of biotransformation as a mechanism of tolerance to natural and man-made toxic agents; impacts of endocrine disrupting chemicals on aquatic organisms; and mechanisms of PAH developmental toxicity in fish.

Research Group:

    Representative Publications:

    • Jordan Crago and Daniel Schlenk (2015) The effect of bifenthrin on the dopaminergic pathway in juvenile rainbow trout (Oncorhynchus mykiss). Aquatic Toxicology 162:66-72.
    • Gabriela Rodríguez-Fuentes, Fernando J. Rubio-Escalante, Elsa Noreña-Barroso, Karla S. Escalante-Herrera, Daniel Schlenk (2015) Impacts of oxidative stress on acetylcholinesterase transcription, and activity in embryos of zebrafish (Danio rerio) following chlorpyrifos exposure. Comparative Biochemistry Physiology 172-173:19-25.
    • Thiago Scremin Boscolo Pereira, Camila Nomura Pereira Boscolo, Danilo Grünig Humberto da Silva, Sergio Ricardo Batlouni, Daniel Schlenk, Eduardo Alves de Almeida (2015) Anti-androgenic activities of diuron and its metabolites in male Nile tilapia (Oreochromis niloticus). Aquatic Toxicology 164:10–15.
    • Alvine C. Mehinto, Ai Jia, Shane A. Snyder, B. Sumith Jayasinghe, Nancy D. Denslow, Jordan Crago, Daniel Schlenk, Christopher Menzie, Sandy D. Westerheide, Frederic D.L. Leusch, Keith A. Maruya (2015) Interlaboratory comparison of in vitro bioassays for screening of endocrine active chemicals in recycled water. Water Research 83:303-309.
    • Lindley A. Maryoung, Ramon Lavado, Theo K. Bammler, Evan P. Gallagher, Patricia L. Stapleton, Richard P. Beyer, Federico M. Farin, Gary Hardiman, Daniel Schlenk (2015) Differential Gene Expression in Liver, Gill, and Olfactory Rosettes of Coho Salmon (Oncorhynchus kisutch) After Acclimation to Salinity. Marine Biotechnology 17:703-717.
    • Varenka Lorenzi, Ree Choe, Daniel Schlenk (2016) Effects of environmental exposure to diazepam on the reproductive behavior of fathead minnow, Pimephales promelas. Environmental Toxicology 31: 561–568.
    • Keith A. Maruya, Nathan G. Dodder, Alvine C. Mehinto, Nancy D. Denslow, Daniel Schlenk, Shane A. Snyder and Stephen B. Weisberg (2016) A tiered, integrated biological and chemical monitoring framework for contaminants of emerging concern (CECs) in aquatic ecosystems. Integrated Environmental Assessment and Management 12(3), 540-547.
    • Aileen Maldonado, Amber Johnson, Deborah Gochfeld, Marc Slattery, Gary K. Ostrander, Jon-Paul Bingham, Daniel Schlenk (2016) Hard Coral (Porites lobata) extracts and homarine on Cytochrome P450 expression in Hawaiian butterflyfishes with different feeding strategies. Comparative Biochemistry and Physiology 179:57-63.
    • Geoffrey Ivan Scott, Dwayne E. Porter, G. Tom Chandler, R. Sean Norman, C. Hart Scott, Miguel Ignacio Uyaguari-Diaz, Keith Maruya, Steve B. Weisberg, Michael H. Fulton, Ed F. Wirth, Janet Mooore, Paul L. Pennington, Daniel Schlenk, George P. Cobb, Nancy D. Denslow (2016) Antibiotics as CECs: An Overview of the Hazards Posed by Antibiotics and Antibiotic Resistance. Frontiers in Marine Science 3:24. doi: 10.3389/fmars.2016.00024.
    • Allison Kupsco Daniel Schlenk (2016) Stage susceptibility of Japanese medaka (Oryzias latipes) to selenomethionine and hypersaline developmental toxicity. Environmental Toxicology and Chemistry 35:1247-1256.
    • Jordan Crago, Cindy Bui, Sanji Grewal, Daniel Schlenk (2016) Age-Dependent Effects in Fathead Minnows from the anti-diabetic drug Metformin. General and Comparative Endocrinology 232: 185-90.
    • Thiago Scremin Boscolo Pereira, Camila Nomura Pereira Boscolo, Andreia Arantes Felício, Sergio Ricardo Batlouni, Daniel Schlenk, Eduardo Alves de Almeida (2016) Estrogenic activities of diuron metabolites in female Nile tilapia (Oreochromis niloticus). Chemosphere 146:497-502.
    • Shirin Mesbah Oskul, Graciel Diamante, Chunyang, Liao, Wei, Shi, Jay Gan, Daniel Schlenk, William H. Grover (2016) Assessing and reducing the toxicity of 3-D printed parts. Environmental Science and Technology Letters 3:1-6.
    • Augustine Arukwe, Jan Myburgh, Håkon A. Langberg, Aina O. Adeogun, Idunn Godal Braa, Monika Moeder, Daniel Schlenk, Jordan Paul Crago, Francesco Regoli, Christo Botha (2016) Developmental alterations and endocrine-disruptive responses in farmed Nile crocodiles (Crocodylus niloticus) exposed to contaminantsfrom the Crocodile River, South Africa. Aquatic Toxicology 173: 83-93.
    • Jordan Crago, Elvis Genbo Xu, Allison Kupsco, Fang Jia, Alvine C. Mehinto, Wenjian Lao, Keith A. Maruya, Jay Gan and Daniel Schlenk (2016). Trophic transfer and effects of DDT in male hornyhead turbot (Pleuronichthys verticalis) from Palos Verdes Superfund site, CA (USA) and comparisons to field monitoring. Environmental Pollution 213:940-948.
    • Elvis Genbo Xu, Cindy Bui, Cassandra Lamerdin, Daniel Schlenk (2016). Spatial and temporal assessment of environmental contaminants in water, sediments and fish of the Salton Sea and its two primary tributaries, California, USA, from 2002-2012. Science of the Total Environment 559:130–140.
    • Aileen Maldonado, Ramon Lavado, Sean Knuston, Marc Slattery, Sridevi Ankisetty, Jared V Goldstone, Kayo Watanabe, Eunha Hoh, Rama S Gadepalli, John M. Rimoldi, Gary K. Ostrander, Daniel Schlenk (2016) Biochemical Mechanisms for Geographical Adaptations to Novel Toxin Exposures in Butterflyfish. PLOS one Volume: 11 Issue: 5: e0154208.
    • Elvis Genbo Xu, Edward M. Mager, Martin Grosell, Christina Pasparakis, Lela S. Schlenker, John D. Stieglitz, Daniel Benetti, E.Starr Hazard, Sean M. Courtney, Graciel Diamante, Juliane Freitas, Gary Hardiman, Daniel Schlenk (2016) Time- and oil-dependent transcriptomic and physiological responses to Deepwater Horizon oil in mahi-mahi (Coryphaena hippurus) embryos and larvae. Environmental Science and Technology 50: 7842-7851.
    • Allison Kupsco, Daniel Schlenk (2016) Molecular Mechanisms of Selenium-Induced Spinal Deformities in Fish. Aquatic Toxicology 179:143-150.
    • Susanne M. Brander, Molly K. Gabler, Nicholas L. Fowler, Richard E. Connon, and Daniel Schlenk (2016) Pyrethroid pesticides as endocrine disruptors: Molecular mechanisms in vertebrates with a focus on fishes. Environmental Science and Technology 50:8977-8992.
    • Andréia A. Felício, Jordan Crago, Lindley A. Maryoung, Eduardo A. Almeida, Daniel Schlenk (2016). Effects of alkylphenols on the biotransformation of diuron and enzymes involved in the synthesis and clearance of sex steroids in juvenile male tilapia (Oreochromus mossambica). Aquatic Toxicology 180:345-352.
    • Juliane, Freitas, Allison Kupsco, Graciel Diamante, Andreia Felicio, Eduardo Alves de Almeida, Daniel Schlenk (2017) Influence of temperature on the thyroidogenic effects of Diuron and its metabolite 3,4-DCA in tadpoles of the American bullfrog (Lithobates catesbeianus). Environmental Science and Technology (in press).
    • Allison Kupsco, Daniel Schlenk (2017) Developmental Expression and Regulation of Flavin-containing monooxygenase by the Unfolded Protein Response in Japanese Medaka (Oryzias latipes). Comparative Biochemistry and Physiology C. 191:7-13.
    • Allison Kupsco, Daniel Schlenk (2017) Comparative developmental toxicity of desalination brine and sulfate-dominated saltwater in a euryhaline fish. Archives of Environmental Contamination and Toxicology 72:294-302.
    • Elvis Genbo Xu, Edward M. Mager, Martin Grosell, E. Starr Hazard, Gary Hardiman, Daniel Schlenk (2017) Novel transcriptome assembly and comparative toxicity pathway analysis in mahi-mahi (Coryphaena hippurus) embryos and larvae exposed to Deepwater Horizon oil. Scientific Reports | 7:44546 | DOI: 10.1038/srep44546
    • Chunyang Liao, Allison Taylor, William F. Kenny, Daniel Schlenk, Jay Gan (2017) Historical Record and Fluxes of DDTs at the Palos Verdes Shelf Superfund Site, California. Science of the Total Environment 581-582: 697-704.
    • Gabrielle do Amaral e Silva Müller; Daína de Lima; Flávia Lucena Zacchi; Rômi Sharon Piazza; Karim Hahn Lüchmann; Jacó Joaquim Mattos; Daniel Schlenk; Afonso Celso Dias Bainy (2017) Analysis of transcriptional responses of normalizing genes on Crassostrea brasiliana under different experimental conditions. Environmental Toxicology and Chemistry 36:2190-2198.
    • Graciel Diamante; Norma Menjivar-Cervantes; Man S Leung; David Volz; Daniel Schlenk (2017) Evaluation of G protein-coupled estrogen receptor (GPER) to 17β-estradiol-induced developmental toxicity in zebrafish Aquatic Toxicology 186 (2017) 180–187.
    • Shirin Mesbah Oskui, Heran C. Bhakta, Graciel Diamante, Huinan Liu, Daniel Schlenk, and William H. Grover (2017) Measuring the Mass, Volume, and Density of Microgram-Sized Objects in Fluid. PLOS ONE 12(4) e0174068.
    • Nicholas C. Pflug, Allison Kupsco, Edward P. Kolodziej Daniel Schlenk; Lynn M. Teesch, James B. Gloer, David M. Cwiertny (2017) Formation of bioactive transformation products during glucocorticoid chlorination. Water Research & Technology 3(3): 450-461.
    • Scott Coffin, Jay Gan and Daniel Schlenk (2017) Comparisons of field and laboratory estimates of risk of DDTs from contaminated sediments to humans that consume fish in Palos Verdes, California, USA. Science of the Total Environment 601-602, 1139-1146.
    • Graciel Diamante, Gabrielle do Amaral e Silva Müller, Norma Menjivar-Cervantes, Genbo Xu, David C. Volz, Afonso Celso Dias Bainy and Daniel Schlenk (2017) Regioselective developmental toxicity of hydroxylated chrysenes in zebrafish embryos. Aquatic Toxicology 189:77–86.
    • Qiuguo Fu, Jianbo Zhang, Dan Borchardt, Daniel Schlenk, and Jay Gan (2017). Direct conjugation of emerging contaminants in Arabidopsis: Indication for an overlooked risk in plants? Environmental Science and Technology 51:6071-6081.
    • Elvis Genbo Xu, Edward M. Mager, John Steiglitz, Martin Grosell, E. Starr Hazard, Gary Hardiman, Daniel Schlenk (2017) Developmental transcriptomic analyses for mechanistic insights into critical pathways involved in embryogenesis of pelagic mahi-mahi (Coryphaena hippurus). PLOS one 12(7): e0180454 .
    • Elvis Genbo Xu, Alex J. Khursigara, Jason Magnuson, E. Starr Hazard, Gary Hardiman, Andrew J. Esbaugh, Aaron. P. Roberts, Daniel Schlenk (2017). Larval red drum (Sciaenops ocellatus) sublethal exposure to weathered Deepwater Horizon crude oil: Developmental and transcriptomic consequences. Environmental Science and Technology (in press).
    • Edmond Sanganyado, Zhijiang Lua, Qiuguo Fu, Daniel Schlenk, Jay Gan (2017) Chiral Pharmaceuticals: A Review on Their Environmental Occurrence and Fate Processes. Water Research 124:527-542.
    • Luísa Becker Bertotto, Jaben Richards, Jay Gan, David Christopher Volz and Daniel Schlenk (2017) Effects of Bifenthrin Exposure on the Estrogenic and Dopaminergic Pathways in Zebrafish Embryos and Juveniles. Environmental Toxicology and Chemistry (in press).

    Courses Taught:

    • ENTX 101 Fundamentals of Toxicology
    • ENTX 208/ ENSC 208 Ecotoxicology
    • ENTX 205 Biotransformation of Organic Chemicals
    • ENSC 001 Introduction to Natural Resources
    • ENSC 191 Seminar in Professional Development

    Graduate Program Affiliations and Research Focus Areas:

    Honors and Awards

    Daniel Schlenk, Ph.D. is Professor of Aquatic Ecotoxicology and Environmental Toxicology at the University of California Riverside. Dr. Schlenk received his PhD in Toxicology from Oregon State University in 1989. He was supported by a National Institute of Environmental Health Science postdoctoral fellowship at Duke University from 1989-1991. A Fellow of AAAS, he has served on two Scientific Advisory Panels supported by the California State Water Board in the USA focused on the monitoring of recycled and surface waters for Emerging Contaminants. Since 2016, he has been a permanent member of the USEPA Chemical Safety Advisory Committee, and from 2007-2014, he was a permanent member of the USEPA FIFRA Science Advisory Panel, which he Chaired from 2012-2014. He is currently an Associate Editor for Environmental Science and Technology, and ES&T Letters. He was co-editor-in chief of Aquatic Toxicology from 2005-2011 and currently serves on its editorial board as well as the editorial boards of Toxicological Sciences, and Marine Environmental Research. He has published more than 250 peer reviewed journal articles and book chapters on the identification of Molecular Initiating and Key Events within Adverse Outcome Pathways for emerging and legacy contaminants in wildlife and humans. He has particular expertise in the linkage of molecular and bioanalytical responses associated with neuroendocrine development and whole animal effects on reproduction, growth and survival. He has been a recipient of the Ray Lankester Investigatorship of the Marine Biological Association of the United Kingdom; a visiting Scholar of the Instituto Del Mare, Venice Italy; a visiting Scholar in the Department of Biochemistry, Chinese University of Hong Kong; a Visiting Scientist at the CSIRO Lucas Heights Laboratory, in Sydney Australia, a Distinguished Fellow of the State Key Laboratory for Marine Environmental Science of Xiamen University, China, and Outstanding Foreign Scientist at Sungkyunkwan University in Korea. His research is supported by funding from the USGS, NIEHS (Superfund Research Program), and USDA.


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    University of California, Riverside
    900 University Ave.
    Riverside, CA 92521
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    Environmental Sciences
    Geology 2460

    Tel: (951) 827-5116
    Fax: (951) 827-4652