Fish and invertebrate sensitivity to the aquatic herbicide aquakleen®

Abstract

Aquakleen® is a common herbicide used to control invasive aquatic plants, and its active ingredient is the butoxyethyl ester of 2, 4-dichlorophenoxyacetic acid (2, 4-D). The effects of 2, 4-D on brook trout (Salvelinus fontinalis), walleye (Sander vitreus), fathead minnow (Pimephales promelas), and the amphipod Hyallela azteca were observed in static acute toxicity tests in the laboratory. The 96-hr LC5Os for brook trout, walleye, and fathead minnow were respectively 0.76, 0.66, and 2.22 mg/L. The 48-hr LC50 for H. azteca was 0.60 mg/L. During three summers in two different lakes, juvenile walleye, brook trout, and/or fathead minnow held in screened enclosures were exposed to 2, 4-D in a controlled manner when the lakes were selectively treated with the herbicide for routine plant control. Reference fishes held in untreated areas of the lakes were also monitored. Mortalities offish of all species after one week were variable but were not significantly different between reference and treated fish of any of the three species. © 2006, Copyright Taylor & Francis Group, LLC.