Risk Assessment Flaw Downplays Insecticide’s Link to Bee Kills
Tuesday, August 3rd, 2010(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 […]










