Fipronil blamed for historical bee deaths

Researchers in the UK report new evidence that the pesticide fipronil, not the neonicotinoid imidacloprid, caused a massive die-off of honey bees in France from 1994 to 1998. Both pesticides hit the market in the early 1990s. At the time, beekeepers and environmentalists largely blamed imidacloprid for the bee deaths. Now, Philippa Holder and colleagues at the University of Exeter and Fera Science, a UK public-private venture focused on agricultural science, suggest that fipronil used on sunflowers was more likely the culprit (Proc. Natl. Acad. Sci. U.S.A. 2018, DOI: 10.1073/pnas.1804934115).

The scientists quantified the toxicity of both pesticides to honey bees and used bioassays to determine the likelihood that they would bioaccumulate in bees. They then incorporated the information into a simulation to predict mass mortality in a honey bee population at environmentally relevant concentrations. The researchers determined that bees rapidly eliminate imidacloprid from their bodies, but they bioaccumulate fipronil. So over time, after prolonged exposure, fipronil becomes more lethal to them. Fipronil is associated with kidney, liver, and thyroid problems in humans.

Source: C&EN, December 3, 2018…

Henk Tennekes

di, 04/12/2018 - 11:43

The phenylpyrazole insecticide fipronil is used in Dutch agriculture in seed coating of cabbage, onions and leek, but was also illegally used as treatment against poultry red mite. Crustaceans and aquatic insects have been shown to be highly sensitive to fipronil and its stable degradation products. An environmental quality standard (EQS) for fipronil in Dutch surface water has been set at 0.07 ng / L. As a result of limitations in analytical methodology, with detection limits usually at 10 ng/L or higher, Dutch Water Boards have been unable to demonstrate fipronil in surface water at concentrations up to 150 times above EQS, creating blind spots in most areas of the country. However, measurable fipronil concentrations of up to 130 ng / L have been recorded in onion cultivation areas in the southwestern province of Zeeland. Similar fipronil concentrations in surface water have been observed in California. Given the cumulative nature of toxicity, the reported fipronil emissions are bound to cause lethal effects in aquatic organisms.

Source: H.A. Tennekes (2018) J Ecol Toxicol 2:111