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.

由于对用于控制旧金山河口入侵水草的新型除草剂的非目标毒性的担忧，我们比较了四种除草剂（五氟磺草胺、咪草啶酸、氟啶酮和草甘膦）对濒危鱼类三角洲胡瓜鱼（ Hypomesus ）的亚致死毒性。跨太平洋航线）。我们测量了雌鱼和雄鱼接触四种除草剂 6 小时后肝脏中 17β-雌二醇 (E2) 和谷胱甘肽 (GSH) 的浓度以及大脑中乙酰胆碱酯酶 (AChE) 的活性。我们的结果表明，氟啶酮和草甘膦破坏了 E2 浓度并降低了肝脏中的谷胱甘肽浓度，而五氟磺草胺、甲咪草烟和氟啶酮则抑制了脑 AChE 活性。暴露于 0.21 μM 氟啶酮的雌性和雄性鱼以及暴露于 0.46、4.2 和 5300 μM 草甘膦的雄性鱼的 E2 浓度显着增加。暴露于 2.8 μM 及更高浓度氟啶酮和 4.2 μM 草甘膦的男性中，GSH 浓度降低。暴露于五氟磺草胺、咪草啶酸和氟啶酮的两性中，AChE 活性均受到显着抑制，并且在女性中观察到更明显的抑制。本研究证明了这些常用除草剂对 Delta Smelt 的潜在有害影响。