New Dutch Study Links IMD to massive honey bee disappearance

Press Release, August 2, 2010
Coalition against Bayer Dangers (Germany)

Imidacloprid: Long-term risks undervalued

Best-selling pesticide worldwide / New study published in Toxicology / Substance linked with bee deaths in various countries / Ban demanded

For many years environmental groups and beekeepers´ organizations have been pushing for a ban on neonicotinoid pesticides which are linked to bee decline across the world. In a recent study, The toxicity of neonicotinoid insecticides to arthropods is reinforced by exposure time, the Dutch toxicologist Henk Tennekes demonstrates that the long-term risks associated with the insecticides imidacloprid and thiacloprid are far greater than hitherto thought. This could actually explain worldwide bee decline. The study was published on the 23rd of July in the journal Toxicology (online).

Dr. Henk Tennekes on his results: “The risks of the neonicotinoid insecticides imidacloprid and thiacloprid to arthropods in water and soil may be seriously underestimated. The acceptable limits are based mainly on short-term tests. If long-term studies were to be carried out, far lower concentrations may turn out to be hazardous. This explains why minute quantities of imidacloprid may induce bee decline in the long run.” Because of their high persistence significant quantities of neonicotinoids may remain in the soil for several years. Consequently, untreated plants growing on soil previously exposed to imidacloprid may take up the substance via their roots and become hazardous for bees.

Henk Tennekes is also concerned about the high level of surface water contamination with relatively stable agrochemicals. The Dutch water boards have detected imidacloprid levels of up to 320 microgram per liter (µg/l). The European Plant Protection Products Directive (91/414/EEC) requires that there is not an unacceptable impact on non-target organisms in the aquatic and terrestrial environment and that the annual average concentration of an active substance or relevant metabolite does not exceed 0.1 microgram per liter in any ground water.

Imidacloprid is the most widely used insecticide in the world and Bayer´s best-selling pesticide (2009 sales: €606 million). The substance is often used as seed-dressing, especially for maize, sunflower and rapeseed. The beginning of the marketing of imidacloprid coincided with the occurrence of large bee deaths, first in France, later on also in many other European countries, Canada, the US and Brazil.

After huge bee mortality in Germany in 2008 which was shown to be caused by neonicotinoid pesticides the Coalition against Bayer Dangers accused the Bayer management of downplaying the risks of imidacloprid, submitting deficient studies to authorities and thereby accepting huge losses of honey bees in many parts of the world. At the same time, German authorities imposed a ban on the use of imidacloprid and its successor product, clothianidin, on maize. Italy and Slovenia imposed a similar ban.

In France imidacloprid has been banned as a seed dressing for sunflowers (since 1999) and maize (since 2004). In 2003 the Comité Scientifique et Technique, convened by the French government, declared that the treatment of seeds with imidacloprid leads to “significant risks for bees”. The consumption of contaminated pollen can cause an increased mortality of care-taking-bees. When individual bees were exposed to sublethal doses their foraging activity decreased and they became disorientated, which researchers concluded “can in the course of time damage the entire colony”. Clothianidin was never approved in France.

we gladly send you a copy of the study

contact Dr. Henk Tennekes: info@toxicology.nl, Tel. +31 575 545500

more information:

Bulletin of Insectology (2010): The puzzle of honey bee losses
Open Letter to the European Union
Campaign for total ban of neonicotinoid pesticides
Charge against Bayer Board introduced
Coalition against BAYER Dangers (Germany)
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