Entomology Commons^™

Effects Of Alachlor On An Algal Community From A Midwestern Agricultural Stream, Rebecca Spawn, Kyle D. Hoagland, Blair Siegfried

Department of Entomology: Faculty Publications

The effects of a single pulse, 21-d exposure of the commonly used herbicide alachlor (2-chloro-2′, 6′-diethyl-N-methoxymethyl acetanilide) on an algal community from a typical agricultural stream in Nebraska were studied using 18 stream microcosms located in a greenhouse, at six alachlor concentrations (0, 1, 10, 30, 100, and 1,000 μg/L). Effects of alachlor exposure at 1.0 μg/L were not significant (p < 0.05); however, at all other concentrations, alachlor had a significant negative effect on algal biomass. Differential taxonomic responses were observed, with approximately half the dominant algal taxa affected at levels >10 μg/L. Some taxa recovered from exposure by day 7, while others took longer or did not recover. A shift in the dominant algae was observed at higher concentrations (30, 100, 1,000 μg/L), and after 21 d these streams …