11
Aug
(Beyond Pesticides, August 11, 2011) A combination of eleven different kinds of commonly used pyrethroids were tested on mice in a new study which found that, at real-world exposure levels, the insecticides can produce heightened toxicity that is equal to the sum of each insecticide’s individual effect. The mixture of similar-acting insecticides works by over-stimulating electronic channels in the mouse’s brain cells and eventually causing death. This study adds to the growing body of research on the toxicity of pesticide combinations in nature and showcases the need for policy change because the current risk assessment approach to regulating pesticides fails to look at chemical mixtures and synergistic effects. The U.S. Environmental Protection Agency (EPA) currently regulates on a chemical-by-chemical basis, but as this study demonstrates, interacting chemicals can have synergistic effects at very low levels, where a “chemical cocktail” of multiple interacting chemicals combine to have greater effects than expected. Pesticides can also have a cumulative “toxic loading” effect both in the immediate and long term. Researchers exposed mice brain cells to eleven different food-use pyrethroid insecticides either singly or in a mixture in the study entitled ”Additivity of pyrethroid actions on sodium influx in cerebrocortical neurons in primary culture.” […]
Posted in Bifenthrin, Cyfluthrin, cypermethrin, Deltamethrin, esfenvalerate, Nervous System Effects, Permethrin | No Comments »
25
Oct
(Beyond Pesticides, October 25,2010) In an effort to control sea lice in farmed Atlantic salmon Health Canada has approved a request by the province of New Brunswick to use the pesticide Alphamax, whose active ingredient is deltamethrin. The high concentrations of salmon in aquaculture facilities has lead to major problems with sea lice, a type of parasitic crustacean that attaches to the fish. Health Canada has approved the use of the restricted pesticide deltamethrin through December of this year. While many salmon farmers are pleased, the decision by Canada’s federal agency has many local fishermen concerned about the effects the pesticide will have on fish and shellfish populations. “Basically we are shocked in a nutshell,” said Grand Manan Fishermen’s Association project manager Melanie Sonnenberg, adding, “Dsappointed doesn’t cover it.” The use of deltamethrin will be restricted to tarped cages or well boats, boats with large holds. Treatment would involve placing fish in the boats, bathing them in Alphamax and releasing them back into cages along with the treated water. The industry is ready to start using the treatment in the Bay of Fundy. Fish farmers have been challenged in controlling sea lice outbreaks this summer, particularly in the upper Passamaquoddy […]
Posted in Deltamethrin, Water | No Comments »
10
Mar
(Beyond Pesticides, March 10, 2010) A study investigating the sublethal effects of pyrethroids, bifenthrin and deltamethrin on honeybees finds that the chemicals significantly impair the pollinators’ reproduction. The researchers also point out that the concentration of each pesticide that produced adverse effects in the experiments was at or below those that bees could encounter while pollinating treated crop fields. “Effects of sublethal concentrations of bifenthrin and deltamethrin on fecundity, growth, and development of the honeybee Apis mellifera ligustica” published in the March issue of Environmental Toxicology & Chemistry, investigated the effects of the two pesticides at sublethal concentrations on fecundity, growth, and development of honeybees were examined with the feeding method for a three-year period (2006-2008). It was shown that both bifenthrin and deltamethrin significantly reduced bee fecundity, decreased the rate at which bees develop to adulthood, and increased their immature periods. Queens in the control group in 2006 laid a little more than 1,200 eggs each day, compared to not quite 900 a day in the bifenthrin group and roughly 600 per day in the deltamethrin group. In general, the hatch rate of pyrethroid-exposed eggs was also significantly depressed. The success rate of hatchlings, that is the share that […]
Posted in Bifenthrin, Deltamethrin, Pollinators | No Comments »
