Sub-lethal effects of herbicides penoxsulam, imazamox, fluridone and glyphosate on Delta Smelt (Hypomesus transpacificus)

Jiali Jin, Tomofumi Kurobe, Wilson F. Ramírez-Duarte, Melissa B. Bolotaolo, Chelsea H. Lam, Pramod Pandey, Tien Chieh Hung, Marie E. Stillway, Leanna Zweig, Jeffrey Caudill, Li Lin, Swee J Teh

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Concerns regarding non-target toxicity of new herbicides used to control invasive aquatic weeds in the San Francisco Estuary led us to compare sub-lethal toxicity of four herbicides (penoxsulam, imazamox, fluridone, and glyphosate) on an endangered fish species Delta Smelt (Hypomesus transpacificus). We measured 17β-estradiol (E2) and glutathione (GSH) concentrations in liver, and acetylcholinesterase (AChE) activity in brain of female and male fish after 6 h of exposure to each of the four herbicides. Our results indicate that fluridone and glyphosate disrupted the E2 concentration and decreased glutathione concentration in liver, whereas penoxsulam, imazamox, and fluridone inhibited brain AChE activity. E2 concentrations were significantly increased in female and male fish exposed to 0.21 μM of fluridone and in male fish exposed to 0.46, 4.2, and 5300 μM of glyphosate. GSH concentrations decreased in males exposed to fluridone at 2.8 μM and higher, and glyphosate at 4.2 μM. AChE activity was significantly inhibited in both sexes exposed to penoxsulam, imazamox, and fluridone, and more pronounced inhibition was observed in females. The present study demonstrates the potential detrimental effects of these commonly used herbicides on Delta Smelt.

Original languageEnglish (US)
Pages (from-to)79-88
Number of pages10
JournalAquatic Toxicology
StatePublished - Apr 1 2018


  • 17β-estradiol
  • Acetylcholinesterase activity
  • Acute toxicity
  • Endocrine disruption
  • Glutathione

ASJC Scopus subject areas

  • Aquatic Science
  • Health, Toxicology and Mutagenesis


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