Insecticides

New research has identified the world’s most widely used insecticides as the key factor in the recent reduction in numbers of farmland birds. The finding represents a significant escalation of the known dangers of the insecticides and follows an assessment in June that warned that pervasive pollution by these nerve agents was now threatening all food production. The neonicotinoid insecticides are believed to seriously harm bees and other pollinating insects, and a two-year EU suspension on three of the poisons began at the end of 2013. Peer-reviewed research, published in the leading journal Nature this Wednesday, has revealed data from the Netherlands showing that bird populations fell most sharply in those areas where neonicotinoid pollution was highest. Starlings, tree sparrows and swallows were among the most affected. At least 95% of neonicotinoids applied to crops ends up in the wider environment, killing the insects the birds rely on for food, particularly when raising chicks.

Imidacloprid, one of the most commonly used insecticides, is highly toxic to bees and other beneficial insects. The regulatory challenge to determine safe levels of residual pesticides can benefit from information about the time-dependent toxicity of this chemical. Using published toxicity data for imidacloprid for several insect species, we construct time-to-lethal-effect toxicity plots and fit temporal power-law scaling curves to the data. The level of toxic exposure that results in 50% mortality after time t is found to scale as t1.7 for ants, from t1.6 to t5 for honeybees, and from t1.46 to t2.9 for termites. We present a simple toxicological model that can explain t2 scaling. Extrapolating the toxicity scaling for honeybees to the lifespan of winter bees suggests that imidacloprid in honey at 0.25 μg/kg would be lethal to a large proportion of bees nearing the end of their life.

Prairie bird populations are falling in many Midwestern states, from ring-necked pheasants to horned larks to sparrows. Scientists now say insecticides are a primary culprit. Minnesota birds are hardest hit with 12 species in decline, followed by Wisconsin with 11, and Illinois, Michigan, Montana, Nebraska and New York with nine affected species each. The recent study looked at a range of possible causes of the population declines, including habitat loss which has long been considered a key driver of the problem. Bird conservationists are “still concerned” about range management, urban development and loss of habitat, but are now focusing additional attention on the harmful impacts of pesticides.

Das Bienensterben bedroht weltweit die Landwirtschaft. Mitverantwortlich dafür sind mutmasslich Pestizide aus der Gruppe der Neonicotinoide. Diese generieren weltweit Milliarden-Umsätze für die Industrie, und sie sind auch im Sortiment des Basler Agrarchemie-Konzerns Syngenta zu finden. Das Produkt von Syngenta heisst Thiamethoxam. Vor einem Jahr kündigte Syngenta die Publikation einer umfassende Studie an: «Wir haben Langzeitstudien gemacht im Mais und im Raps, und damit konnten wir zeigen, dass es bei der Anwendung, wie wir sie empfehlen, zu keinen Bienenschäden kommt», sagte Georg Diriwächter, Leiter Registrierung Pflanzenschutzmittel bei Syngenta.

The mainstream media inexplicably seems to downplay the links between chronic pesticide exposure and birth defects, but a new study is bringing this topic back into view. Applied pesticides don’t just impact farm-workers. They also take a toll on families who live within 2 miles of a farm that uses toxic pesticides, according to the latest research from the MIND Institute at University of California, Davis Medical Center. From birth defects to other developmental issues, early exposure to pesticides isn’t healthy for babies. What are the chemicals we’re exposing people to, and how do they work? The study cites three of the most commonly used agricultural pesticides in the past 50 years. These three classes of pesticides implicated in the study are: organophosphates, pyrethroids, and carbamates.