I understand that Canada’s Pest Management Regulatory Agency recently announced that it “has determined that current agricultural practices related to the use of neonicotinoid-treated corn and soybean seed are affecting the environment due to impacts on bees and other pollinators” (based on findings in Ontario and Quebec). They are applied as seed dressings on wheat and canola on the prairies, and that PMRA is providing an opportunity for public comment. I would like to urge PMRA to conduct a serious, more comprehensive review of the environmental impact of neonicotinoid insecticides. My reasoning is as follows. Insects are quietly but rapidly disappearing. The great American biologist, E O Wilson, said insects were world-rulers, because they play a central role in maintaining ecosystems and the whole web of life. The recent alarms in Europe and America about the fate of the honey bee – colonies have been crashing in increasing numbers – have started to open people’s eyes to insects’ importance in a more general way. But it is only the beginning of an understanding, and much more is needed if we are to take the action necessary to preserve our populations of insects and other invertebrates, the creatures without backbones which make up the majority of animal life, including snails, worms and spiders (spiders being arachnids, not insects).
I understand that Canada’s Pest Management Regulatory Agency recently announced that it “has determined that current agricultural practices related to the use of neonicotinoid-treated corn and soybean seed are affecting the environment due to impacts on bees and other pollinators” (based on findings in Ontario and Quebec). They are applied as seed dressings on wheat and canola on the prairies, and that PMRA is providing an opportunity for public comment. I would like to urge PMRA to conduct a serious, more comprehensive review of the environmental impact of neonicotinoid insecticides. My reasoning is as follows. Insects are quietly but rapidly disappearing. The great American biologist, E O Wilson, said insects were world-rulers, because they play a central role in maintaining ecosystems and the whole web of life. The recent alarms in Europe and America about the fate of the honey bee – colonies have been crashing in increasing numbers – have started to open people’s eyes to insects’ importance in a more general way. But it is only the beginning of an understanding, and much more is needed if we are to take the action necessary to preserve our populations of insects and other invertebrates, the creatures without backbones which make up the majority of animal life, including snails, worms and spiders (spiders being arachnids, not insects).
Chemicals have become a weapon in man’s arsenal against crop-destroying insects and weeds. Fifty million tons of toxins are applied annually to soil and crops in America alone. What these poisons are doing to the entire web of life—and to personal health—began to be known some 40 to 50 years ago. Fifty years ago the scientist Rachel Carson issued a warning, in her epic book Silent Spring, about the dangers of pesticides to birds, insect life, wildlife, the soil, the environment and human health. If we continued to spray a rain of poison indiscriminately over our farms, our wildlife and our environment, she warned, we will end up with a poisoned world in which birds no longer sing. Rachel Carson is considered to be the founder of the environment movement.
She drew attention, for the first time, to the fact that pesticides can degrade the soil, contaminate waterways, kill harmless and beneficial insects and wildlife, and disrupt our eco-systems. She was the first person, too, to warn of the dangers of systemic pesticides that permeate all the tissues of a plant and make them poisonous. The world of systemic insecticides, she warned, is a weird world surpassing the imaginings of the brothers Grimm—it is a world where the enchanted forest of the fairly tales becomes a poisonous forest in which an insect that chews a leaf or sucks the sap of a plant is doomed.’ When her book was published, chemical companies launched a vicious, personal attack on her and ridiculed her claims, and as a result, her warnings were largely ignored, and more and more powerful sprays are being used around the world. Today 5 billion pounds of pesticide are poured onto the planet every year, and it’s almost impossible to find any place on earth where pesticide residues are not detectable. And almost every human being on earth is subject to contact with chemicals from the moment of conception until their death. And now, today, as you read these words, we are in the middle of that forecasted disaster—and are witnesses of an ever-expanding crisis!
I mention all this to provide some historical context for the debate that is raging today about the safety of another class of pesticides called Neonicotinoids, and their effect on honeybees and other pollinators and beneficial insects. Neonicotinoids came onto the market in the early nineties, and quickly became the most widely used insecticide in the world. Over the past couple of years 150 scientific studies on the effects of neonicotinoids on bees have been published, and many of these confirm that they are extremely toxic to bees, even in tiny sub lethal doses, and have other harmful effects on bee colonies, including losses in the number of queens, a significant increase in the number of bees that fail to return from food foraging trips, and impairment of their memory, grooming behaviour and ability to navigate.
I am the author of a book entitled ‘the Systemic Insecticides, a Disaster in the Making,’ in which I argue that so many insects that are vital to our survival are being wiped out as a result of the extensive soil and water contamination by neonicotinoid pesticides that we are witnessing ‘an ecological collapse before our eyes.’ I point out that most bird and insect species are already struggling to survive, and have declined by around 65-70% in the past half century, in some countries. Further declines in insects and birds as a result of our continuing widespread use of neonicotinoid pesticides, will create an ecological disaster, I predict. Graham White, an environmental author who keeps bees in Scotland, shares my concern. “We are witnessing an ecological collapse in all the wildlife that used to live in fields, hedgerows, ponds and streams. All the common species we knew as children are being wiped out from the face of the countryside. Canadian wildlife biologist Neil Dawe says he wouldn’t be surprised if the generation after him witnesses the extinction of humanity. All around him, even in a place as beautiful as the Little Qualicum River estuary, his office for 30 years as a biologist for the Canadian Wildlife Service, he sees the unravelling of “the web of life.” “It’s a veritable desert here.” The loss to the food web is a loss to the web of life, he says, and people are a huge part of that web.
A central question confronting scientists investigating the causes of bee decline is the impact of the low concentrations of neonics now widespread in the environment that honey bees are likely to encounter. A new review paper by Francisco Sanchez-Bayo and myself in the journal Toxicology (Volume 309, July 5, 2013, pages 39–51, attached) suggests that very low concentrations of neonics can have devastating effects on bees and—here’s the most important part—that conventional risk assessment approaches can miss or underestimate those effects.
According to the paper, neonics are in a group of chemicals, called time-dependent chemicals, whose toxic effects build up during long exposure times. The paper suggests that time-dependent phenomena occur when an insecticide binds very tightly or irreversibly to critical receptors in the target organism. Given a long enough exposure, even very low levels of time-dependent chemicals can kill. Standard toxicity tests, which focus on the concentration of toxins for relatively short time periods, do not pick up time-dependent effects because they fail to expose target organisms to very low concentrations of a toxin over long enough periods of time.
We use imidacloprid as a test case to demonstrate how standard risk assessment protocols can miss the harmful effects low levels of the chemicals can have on honey bees. The paper assessed the impact of imidacloprid on honey bees by determining the time it took for 50 percent of the bees to die (t50) when exposed for varying time intervals to low doses of the chemical. It then related the exposure data to the pesticide concentrations typically found as plant residues under field conditions and calculated that 50 percent of worker bees would die within seven to ten days if they fed on a such a field. By contrast, we assert that standard risk assessments suggest field concentrations of imidacloprid pose no risks at all to honey bees. We propose a new risk assessment protocol based on t50s to evaluate the effects of time-dependent chemicals and recommend that going forward regulatory agencies employ such protocols to assess the harmful effects of neonics. Regulators should consider these recommendations. Pollinators are too important to agriculture and other ecosystems, and neonics too widely used, for regulators to be ignorant of the threats low levels of these pesticides pose.
I summarize my deep concerns: “The article reviews a paradigm shift in the science of toxicology. The dose : response characteristics of neonicotinoid insecticides turn out to be identical to those of genotoxic carcinogens, which are the most dangerous substances we know. Such poisons can have detrimental effects at any concentration level. Current pesticide risk assessment procedures are flawed and have failed to protect the environment. Traditional approaches that consider toxic effects at fixed exposure times are unable to allow extrapolation from measured endpoints to effects that may occur at other times of exposure. Time-to-effect approaches that provide information on the doses and exposure times needed to produce toxic effects on tested organisms are required for prediction of toxic effects for any combination of concentration and time in the environment.”
Katherine E. Gibbs et al. ( Diversity and Distributions (2009) 15: 242–253) statistically compared areas in Canada where imperiled species currently occur, versus areas where they have been lost. Using multiple regressions, they related the numbers of species that had suffered range reductions in an ecoregion to variables that represent present habitat loss, pesticide use and human population density. They found high losses of imperiled species in regions with high proportions of agricultural land cover. However, losses of imperiled species were significantly more strongly related to the proportion of the region treated with agricultural pesticides. The relationship between species losses and area treated with pesticides remained significant after controlling for area in agriculture. Their results are consistent with the hypothesis that agricultural pesticide use has contributed significantly to the decline of imperiled species in Canada. Habitat conversion per se may be a less important cause of species declines than how that converted habitat is used.
Many groups of organisms found in agricultural areas are experiencing catastrophic declines, including: birds (e.g., Nebel, S. et al. 2010. Declines of aerial insectivores in North America follow a geographic gradient. Avian Conserv. Ecol. 5(2): 1. [online]); bats (e.g., Wickramasinghe, L.P. et al. 2004. Abundance and species richness of nocturnal insects on organic and conventional farms: effects of agricultural intensification on bat foraging. Conserv. Biol. 18: 1283–1292); amphibians (e.g., Blaustein, A.R. 2011. The complexity of amphibian population declines: understanding the role of cofactors in driving amphibian losses. Ann. N. Y. Acad. Sci. 1223: 108-119); bumblebees (e.g., Cameron, S.A. et al. 2011. Patterns of widespread decline in North American bumble bees. Proc. Nat. Acad. Sci. 108(2): 662-667); butterflies (e.g., Van Dyck, H. et al. 2009. Declines in common, widespread butterflies in a landscape under intense human use. Conserv. Biol. 23(4): 957-965); moths (e.g., Conrad, K.F. et al. 2006. Rapid declines of common, widespread British moths provide evidence of an insect biodiversity crisis. Biol. Conserv. 132(3): 271-291); and carabid beetles (Brooks, D. R. et al. 2012. Large carabid beetle declines in a United Kingdom monitoring network increases evidence for a widespread loss in insect biodiversity. J. Appl. Ecol. 49(5): 1009-1019). Exposure to neonicotinoid insecticides is likely to be contributing to these declines, and exposure to these chemicals may be interacting with other negative pressures on biodiversity in agricultural areas.
A huge proportion of Canada’s bird species are in serious decline. Overall, there’s been a 12 per cent drop in bird populations since 1970, says the 36-page report, entitled The State of Canada’s Birds 2012. Forty-four per cent of Canada’s 460-plus species have fallen in number, 66 of them so dramatically they are considered endangered. At the top of the list of most endangered birds is the spotted owl Strix occidentalis, whose numbers have dropped to a mere “handful”, and the great sage grouse Centrocercus urophasianus, with fewer than 100 males, down from thousands 20 years ago. Populations of grassland birds, such as meadowlarks and bobolinks Dolichonyx oryzivorus, have fallen by 45 per cent since 1970; some species that thrive in the long grasses of the Prairies or the farms of Eastern Canada are vulnerable, with numbers that have dropped by 90 per cent. Birds known as aerial insectivores — basically such species as barn swallows Hirundo rustica, chimney swifts Chaetura pelagica and flycatchers that snatch insects on the wing — are still relatively common, but have seen an overall descent in numbers of 64 per cent. I suggest that neonicotinoid insecticides are contributing to these declines.
Yours sincerely
Dr. H. A. (Henk) Tennekes
Consultant in Toxicology
Experimental Toxicology Services (ETS) Nederland BV
Frankensteeg 4
7201KN Zutphen, The Netherlands
www.toxicology.nl
www.disasterinthemaking.com
www.farmlandbirds.net
Tel. +31 575545500
