Acute toxicity of Garlon 4 and Roundup herbicides to salmon, Daphnia, and trout

The primary purpose of this study was to broaden knowledge of acute lethality effects of Garlon 4 (an oil soluble, water emulsifiable butoxyethyl ester formulation of triclopyr) and Roundup (combination of glyphosate and MON0818) on three species of salmonids (Oncorhyncus nerka, Salmo gairdneri, and Oncorhyncus kisutch) and Daphnia pulex under different water quality conditions (primarily altering pH and water temperature). Throughout the study, LC50s for Oncorhyncus nerka and Daphnia pulex were similar and lower than those of Oncorhyncus kisutch and Salmo gairdneri. All species were more sensitive to Garlon 4 than Roundup (1.2-2.2 mg/L 96-hr LC50s vs. 25.5-42 mg/L 96-hr LC50s respectively). The authors also found that varying pH and temperatures of the water affected the LC50s of different chemicals, suggesting that more testing would be beneficial to building databases of toxicity of chemicals to species under different environmental conditions.