03
Aug
(Beyond Pesticides, August 3, 2010) A new study shows that due to a flaw in standard risk assessments, which consider toxic effects at fixed exposure times, the risks posed by the neonicotinoid pesticides imidacloprid and thiacloprid are likely to be underestimated. The authors believe that minute quantities of imidicloprid may be playing a much larger role in killing bees over extended periods of time than previously thought. The study, “The significance of the Druckrey—Küpfmüller equation for risk assessment””The toxicity of neonicotinoid insecticides to arthropods is reinforced by exposure time,” was published online July 23, 2010 in the journal Toxicology. The authors believe that standard risk assessment calculations underestimate toxicity because they do not accurately account for the interplay of time and level of exposure. According the study: The essence of the Druckrey—Küpfmüller equation states that the total dose required to produce the same effect decreases with decreasing exposure levels, even though the exposure times required to produce the same effect increase with decreasing exposure levels. Druckrey and Küpfmüller inferred that if both receptor binding and the effect are irreversible, exposure time would reinforce the effect. The Druckrey—Küpfmüller equation explains why toxicity may occur after prolonged exposure to very low toxicant […]
Posted in Acephate, Arizona, Aurora, Biofuels, Children/Schools, Dow Chemical, magnesium phosphide, Pollinators | 1 Comment »
08
Apr
(Beyond Pesticides, April 8, 2010) The U.S. Environmental Protection Agency (EPA) is requiring new restrictions on aluminum and magnesium phosphide products in an attempt to better protect people, especially children, from dangerous exposures. The new restrictions prohibit all uses of the products around residential areas and increase buffer zones for treatment around non-residential buildings that could be occupied by people or animals from 15 feet to 100 feet. Human exposure to these toxic chemicals, though slightly minimized, would nevertheless continue because of their continued availability for use on athletic fields and playgrounds, around non-residential buildings, and in agricultural production. Phosphide fumigants are known to be highly acutely toxic when ingested or inhaled. Symptoms of mild to moderate acute exposure include nausea, abdominal pain, tightness in chest, excitement, restlessness, agitation and chills. Symptoms of more severe exposure include diarrhea, cyanosis, difficulty breathing, pulmonary edema, respiratory failure, tachycardia (rapid pulse) and hypotension (low blood pressure), dizziness and/or death. Aluminum and magnesium phosphide fumigants are used primarily to control insects in stored grain and other agricultural commodities. They also are used to control burrowing rodents in outdoor agricultural and other non-domestic areas. The fumigants are restricted to use by specially trained pesticide applicators. […]
Posted in aluminum phosphide, Children/Schools, Fumigants, magnesium phosphide, Pesticide Regulation, Phosphine, Rodenticide, Rodents | No Comments »
