Effects of the aquatic herbicide, Reward®, on the Fathead minnow and Northwestern Salamander

Date created: 
2018-05-24
Identifier: 
etd10739
Keywords: 
Toxicology
Aquatic herbicide
Reward®, diquat dibromide
Fathead minnow
Northwestern salamander
Abstract: 

In this study the commercial formulation of the aquatic herbicide Reward® (active ingredient diquat dibromide [DB]) was tested. In larval and adult Fathead minnows (Pimephales promelas; FHM) after two 24 h pulse exposures spaced two weeks apart the LC50’s of 4.19 mg/L and 6.71 mg/L were obtained, respectively. A lowest observed effect concentration of 1.18 mg/L for larval growth in FHMs during a 7 d continuous exposure was also derived. An acute 96 h LC50 of 71.5 mg/L DB was obtained for Northwestern salamander (Ambystoma gracile) larvae, while a 21 d continuous exposure LC50 was dramatically lower (1.56 mg/L DB) for these larvae. Few reports of environmental concentrations of this pesticide could be found for Canadian waters. Whether aquatic and/or terrestrial applications and/or DB’s persistent nature in sediments translate into acute or sub-chronic toxicity exposure scenarios in Canadian aquatic systems is unknown and should be the focus of future studies.

Document type: 
Thesis
Rights: 
This thesis may be printed or downloaded for non-commercial research and scholarly purposes. Copyright remains with the author.
File(s): 
Supervisor(s): 
Vicki Marlatt
Department: 
Science: Biological Sciences Department
Thesis type: 
(Thesis) M.Sc.
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