comparative toxicities of five herbicides on nauplii of artemia franciscana as an ecotoxicity bioindicator

Artemia is one of the most important test organisms available for ecotoxicity tests. in this study the toxicity of five widely used herbicide formulations including: paraquat, 2,4-dichlorophenoxy acetic acid (2,4-d), trifluralin, glyphosite and - atrazine were compared using the ecotoxicity bioindicator, artemia franciscana. acute toxicity (48 h lc50) of five herbicides were determined via oecd standard methods. artemia were hatched using standard methods and 12 h old nauplii were used for toxicity evaluation of herbicides. nauplii were exposed to serial concentrations (more than 6 in triplicates) of each herbicid. mortalities at 12, 24, 36 and 48 hours after exposure were recorded and the lc50 were calculated using the probit software. the results showed that the mortality rate increased by increasing the exposure time in all herbicide toxicity assays. besides 48 hours lc50 value of paraquat, 2,4-d, trifluralin, glyphosite and atarzine were calculated at 15.67, 12.93, 11.87, 164.31 and 61.34 mg l^-1 in a. franciscana respectively. glyphosate showed significantly less lethality and toxicity while trifluralin and 2,4-d showed the highest toxicity in a. franciscana among the examined herbicides. then for sustainable agricultural activity, especially in areas that runoff water flows into aquatic ecosystems, it is highly recommended to use environmentally friendly herbicides like –glyphosate as an alternative to the highly toxic herbicides like trifluralin, paraquat and 2,4-d.