In summer 2012, we initiated a large-scale field experiment in southern Ontario, Canada, to determine whether exposure to clothianidin seed-treated canola (oil seed rape) has any adverse impacts on honey bees. Colonies were placed in clothianidin seed-treated or control canola fields during bloom, and thereafter were moved to an apiary with no surrounding crops grown from seeds treated with neonicotinoids. Colony weight gain, honey production, pest incidence, bee mortality, number of adults, and amount of sealed brood were assessed in each colony throughout summer and autumn. Samples of honey, beeswax, pollen, and nectar were regularly collected, and samples were analyzed for clothianidin residues. Several of these endpoints were also measured in spring 2013. Overall, colonies were vigorous during and after the exposure period, and we found no effects of exposure to clothianidin seed-treated canola on any endpoint measures. Bees foraged heavily on the test fields during peak bloom and residue analysis indicated that honey bees were exposed to low levels (0.5–2 ppb) of clothianidin in pollen. Low levels of clothianidin were detected in a few pollen samples collected toward the end of the bloom from control hives, illustrating the difficulty of conducting a perfectly controlled field study with free-ranging honey bees in agricultural landscapes. Overwintering success did not differ significantly between treatment and control hives, and was similar to overwintering colony loss rates reported for the winter of 2012–2013 for beekeepers in Ontario and Canada. Our results suggest that exposure to canola grown from seed treated with clothianidin poses low risk to honey bees.

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Since the 1960s, mink (Mustela vision) populations in Georgia, North Carolina, and South Carolina have declined, especially in the coastal plain. A prior study suggested that the decline may stem from environmental contaminants. Based on water quality data from each state, we identified 17 substances potentially related to the decline: aldrin, dieldrin, endrin, DDD, DDE, DDT, PCBs, chlordane, alpha-BHC, toxaphene, dibenzofuran, copper, chromium, cadmium, lead, arsenic, and mercury. Mink livers were analyzed for PCB and organochlorine pesticides, and kidneys and femurs were analyzed for metals. Reference sample concentrations from piedmont, mountain, and foothill locations were compared to state coastal plain totals and counties. PCBs for Georgia, dieldrin for South Carolina, and endrin and aldrin for North Carolina were significantly higher than the piedmont reference group. Liver PCB concentrations were higher than those known to cause mink reproductive dysfunction. Mercury concentrations were significantly higher in coastal plain mink from all three states and were in the range of those known to cause impacts to reproduction, growth, and behavior to wild mink. It is unknown what concentrations of cyclodienes cause reduced reproduction or other physiological effects in mink, but the levels reported here probably indicate background concentrations that do not contribute to the decline.

Twenty mallards (Anas platyrhynchos) of both sexes were dosed by oral gavage with Heavi-Shot (H-S; Environ-Metal, Inc., Sweet Home, Oregon, USA) pellets, 20 with steel shot, and 10 with lead (Pb) pellets, all of equal size. All pellets were fired from a shotgun into an absorbent material, retrieved, and weighed prior to introduction into the ducks. Birds were fed whole kernel corn and grit and observed for signs of toxicity for 30 days following dosing. HeviShot pellets lost an average of 6.2% of their mass and steel shot pellets lost 57% of their mass in the birds' gizzards. Almost all (90%) of the Pb shot dosed birds died before the end of the study, while no mortality was observed in the steel or H-S dosed groups. Even though total food consumption differed between the H-S and steel shot groups, mean bird weight change was not different. There were no significant morphologic or histopathologic abnormalities of the liver and kidney in the H-S and steel shot groups. Results indicated that mallards dosed orally with eight No. 4 H-S pellets were not adversely affected over a 30-day period, and that H-S provides another environmentally safe nontoxic shot for use in waterfowl hunting.