Risk assessment for honeybees from pesticide-exposed pollen

A method for assessing the risk for honeybees from pesticide exposure via p ollen is proposed. Four pesticides, selected as markers, were monitored in pollen samples collected in two sampling areas, one located in an intensive agricultural area and the other far from direct pesticide impact. Analytic al results were consistent with use patterns of the chemicals and their phy sico-chemical and persistence properties. For a preliminary estimate of bee exposure via pollen, both by ingestion and by contact, an exposure index w as developed, based on physico-chemical properties, persistence and applica tion rates. On the basis of the exposure estimates and acute toxicological data (ingestion and contact LD50), Toxicity Exposure Ratios (TERs) were cal culated as indicators of the risk for honeybees due to this particular expo sure route. TER values were compared to Hazard Quotient (HQ), calculated as the ratio between application rate and the LC50 value, according to Europe an guidelines, showing a satisfactory agreement. The advantage of the above described procedures is that the environmental fate of the chemicals, and not only application rates, are taken into account. This approach may repre sent a preliminary tool for a comparative screening of the risk for pollina tor insects due to this particular exposure route.