Toxicity evaluation of some herbicides by echo toxicant bioindicator: Daphnia magna

Evaluation of herbicide pollution in aquatic environments needs the great concern and the most important echo-pollutant effects of herbicides are related to their effects on non-target aquatic organisms. In last decades the herbicides are widely used in agriculture and they are important echo-pollutant in aquatic ecosystems. Daphnia magna is an important and reliable bio-indicator of toxicity and pollution in aquatic environments. Then in this study the acute toxicity of three widely used herbicides including Paraquat, Glyphosite and Atrazine were investigated. The acute toxicity test of herbicides was conducted following the Organization for Economic Cooperation and Development (OECD) under static-renewal test. Daphnia exposed to serial dilution of each herbicide in triplicate for ۴۸ hours, Mortality after ۱۲, ۲۴, ۳۶ and ۴۸, were recorded and analysed using probit software. Maximum Acceptable Concentration (MAC) measured for each herbicide. Results showed that acute toxicity of these three herbicides: were significantly different using daphnia magna. The ۴۸h LC۵۰ of in Daphnia in Paraquat, Glyphosite and Atrazine were ۲.۳, ۱۷۰.۴ and ۳۵.۵ mg/L respectively. Results indicated that Glyphosite induced the lowest toxicity based on daphnia bio indicator method whereas Paraquat showed the highest toxicity compare to other herbicides. Atrazine toxicity was lower than paraquate and higher than Glyphosite. The mortality rate of daphnia enhanced along with increasing concentration of both herbicides as well as exposure duration. Comparatively Glyphosite showed significantly lower toxicity in daphnia compare with two other herbicides. Due to the widespread and increasing use of these widespread herbicides in agriculture industry along with significantly lower toxicity of Glyphosite on Daphnia magna, as a reliable echo toxicity bio-indicator, it can be concluded that Glyphosite is highly recommendable as an environmentally friendly herbicide in agriculture and aquaculture. Based on our findings Glyphosite can be used as a proper alternative for other herbicides particularly in human habitat area.

Keywords:

Paraquat , Glyphosite , Atrazine , Daphnia magna , Acute toxicity