Herbicides

We have recently been surveying what chemicals the local farmers in East Sussex use each year. Chemicals applied to two fairly typical fields, one with winter oilseed rape, one with winter wheat, in a single growing season (2012/13). I should stress that these are perfectly normal farms; not especially intensive, situated on the edge of the South Downs, an area of gentle hills, hedgerows and wooded valleys. Beautiful, rural England; Constable would have liked it here. But let’s look at it from a bee’s perspective, focussing on the oilseed rape, since this is a crop they will feed on when it flowers: firstly, the crop is sown in late summer with a seed dressing containing the insecticide thiamethoxam. This is a systemic neonicotinoid, with exceedingly high toxicity to bees. We know it is taken up by the plant, and that detectable levels will be in the nectar and pollen gathered by bees in the following spring. In November, despite the supposed protection of the neonicotinoid, the crop is sprayed with another insecticide, the charmingly named Gandalf. Gandalf contains beta-cyfluthrin, a pyrethroid. Pyrethroids are highly toxic to bees and other insects, but there should be no bees about in November so that is probably OK. The following May, when it is flowering, the crop is sprayed with another pyrethroid, alpha-cypermethrin. Less than three weeks later, the crop is blitzed with three more pyrethroids, all mixed together, a real belt-and-braces approach. Why use one when three will do? The crop is still flowering at this point (it was a late year), and would be covered in foraging bumblebees and other pollinators. In between, the crop is also treated with a barrage of herbicides, fungicides, molluscicides and fertilizers – 22 different chemicals in total.

Pesticides have been linked to Parkinson’s disease, declines in cognitive performance, developmental disorders, and attention-deficit/hyperactivity disorder in children. Their application has also been tied to environmental issues, such as the collapse of honeybee colonies and the development of resistant pests and weeds. But we know surprisingly little about population-wide health effects of the low doses that are in the foods we eat every day, panelists at the Harvard School of Public Health said Thursday. “We can’t tell for sure if you eat a bowl of salad today for lunch if it will lead to cancer in 10 to 20 years,” said Chensheng Lu, an associate professor of environmental exposure biology at the Harvard School of Public Health. Lu, whose recent research has tracked the mysterious collapse of honeybee colonies to a class of pesticides called neonicotinoids, said that broad studies on the effects of pesticide residue in foods are difficult to do. Funding is hard to attract because there isn’t a specific health impact being investigated. Also, there are daunting challenges to designing a scientifically valid study, stemming from the fact that so much of the population has been raised on foods treated with chemicals.

L'éditeur de Food and Chemical Toxicology applique deux poids deux mesures en matière de publication en faveur de l'industrie. Face à ce flagrant délit, le groupe Elsevier l'a obligé à publier un droit de réponse de l'équipe Séralini & al. Plus d’un an après publication, le rédacteur en chef de Food and Chemical Toxicology (FCT), Dr A. Wallace Hayes, retirait l'étude de toxicologie de long terme sur deux produits de Monsanto, le maïs OGM (NK603) et son herbicide associé (Roundup) de l'équipe Séralini & al, tout en reconnaissant ni fraude ni mauvaise interprétation intentionnelle. Dans un nouvel article publié dans les colonnes de FCT, grâce à la pression du groupe éditorial Elsevier, les chercheurs expliquent pourquoi ils n’acceptent pas les conclusions du Dr Hayes : ils dénoncent l’absence de sérieux des raisons scientifiques évoquées, réfutent la prétendue sensibilité des rats et précisent les statistiques approfondies portant sur les paramètres sanguins et urinaires perturbés, confirmant les pathologies hépatiques, rénales, et les tumeurs mammaires.

The editor of Food and Chemical Toxicology (FCT) uses double standards when it comes to publishing in favour of the industry, Prof. Séralini’s team say. Now the journal’s publisher Elsevier has compelled him to publish a right of reply by the Séralini team. More than a year after its publication, the editor of Food and Chemical Toxicology (FCT), Dr A. Wallace Hayes, retracted the long-term toxicity study on two Monsanto products, the NK603 GM maize and its associated herbicide Roundup by Séralini et al. He did so despite the fact that he found neither fraud nor conscious misinterpretation in the study. In a new article published in FCT, following pressure from the journal’s publisher Elsevier, the scientists explain why they do not accept Dr Hayes’ conclusion. They denounce the lack of scientific validity of the reasons given for the reatraction, explain why the Sprague-Dawley rat strain used is appropriate, and describe the statistical results in depth concerning the blood and urine parameters affected, proving that the liver and kidney pathologies and the mammary tumours are solidly based.

EFSA has published new guidance that enables scientists to carry out a specialised aspect of environmental exposure assessment for pesticides. The guidance document provides a clear methodology for evaluating studies that measure the time required for the actual degradation of 50 % of a chemical pesticide and its transformation products in soil. This is known as the DegT50 value. Importantly, it allows users to exclude the effects of dissipation, another process that causes pesticide residues to disappear from soil. The guidance is aimed primarily at risk assessors and industry applicants and allows them to derive DegT50 values, critical information for the safety evaluation of pesticides. EFSA has developed the guidance document as part of its ongoing work in the field of pesticides to safeguard the environment. The methodology can be also applied to chemicals released into soil from non-pesticide uses.