How neonicotinoids contaminate entire ecosystems

Neonicotinoids are a class of neurotoxic chemicals that are structurally similar to nicotine, a powerful natural insecticide that is harmful to mammals. Neonicotinoids were designed to be more targeted to insects and less broadly destructive, but recent research suggests widespread impacts.

It’s the Smoking Gun. A groundbreaking report published in July by the international peer-reviewed journal PLOS ONE has shed new light on the plight of honeybees. Taken all together, the evidence indicates that bees are at risk from a multitude of factors.

Although the plight of pollinators is familiar news, the winter of 2012-13 was particularly catastrophic. Some Ontario beekeepers lost 70 per cent of their colonies. Overall, Canada lost nearly 30 per cent – roughly 200,000 bee colonies. These losses spell hardship and even disaster for honey producers, but the role of bees and other pollinators is crucial for global agriculture, contributing an estimated $200-billion in ecological services.

Many factors are blamed: cold, wet weather, malnutrition and habitat loss. A growing number of beekeepers are implicating neonicotinoids (aka neonics), a class of pesticides used by corn, soybean and canola farmers. George Monbiot says they are “the new DDT” contaminating the agricultural environment. 

Agricultural runoff [in Holland] was so concentrated with imidacloprid that it could be used itself as an effective pesticide.

Reports that the EU has passed a two-year ban on neonics are misleading. A few have been suspended for purposes mainly affecting honeybees – but they continue to be used widely. A May 2013 Dutch study, “Macro-Invertebrate Decline in Surface Water Polluted with Imidacloprid,” found that agricultural runoff was so concentrated with imidacloprid that it could be used itself as an effective pesticide. This toxic runoff is leading to 70-per-cent less aquatic invertebrate species richness and abundance, a factor with unknown consequences for the broader ecosystem.

The American Bird Conservancy commissioned internationally renowned toxicologist Pierre Mineau to research the impact of neonics on birds and aquatic systems. The 100-page report concludes that the chemicals are also lethal to birds and in some areas both surface- and groundwater are contaminated beyond the lethal threshold for many aquatic species.

When the entire ecosystem is examined, it becomes clear how chemicals interact with organisms in complex and unpredictable ways. Up until now, most research has fed bees only one chemical at a time. But the July PLOS ONE article, entitled “Crop Pollination Exposes Honey Bees To Pesticides,” tested how bees are exposed to combinations and loads of pesticides in the real world. It found insecticides in pollen samples at concentrations higher than median lethal doses. It also implicated “fairly safe” fungicides in honeybee population declines. Bees who ingest these fungicides are more susceptible to the parasite Nosema ceranae, which can result in complete colony collapse. Bees are subject to an unsupervised cocktail of chemicals in the environment, putting many other species at risk.

Janet Kimantas is associate editor at A\J with degrees in studio art and environmental studies. She is currently pursuing an MES at UWaterloo. She splits her spare time between walking in the forest and painting Renaissance-inspired portraits of birds.

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