Pollinators and Pesticides - Environmental Audit Committee Contents


Neonicotinoids and human health

The approval process for neonicotinoids, as with other pesticides, includes consideration of the potential effects on human health, both through food crop consumption and through direct exposure by agricultural workers and bystanders. Exposure limits are generally set at one-hundredth of the level at which no acute effects are detected in experimental animals.[176] A 2005 report by the then Royal Commission on Environmental Pollution examined the human health risks of pesticides, which identified an association but not a firm causal link:

We have tried to review the evidence afresh and to reconsider the hypothesis that [individuals'] reported ill health may be linked to pesticide exposure. We are not persuaded that the evidence from individual cases is so weak as to rule out this possibility.[177]

There is no dispute that some people who have been exposed to pesticides have become ill. The dispute has concerned the causality and underlying basis for these illnesses. On the evidence that we have received we cannot draw firm conclusions on causality. But we are persuaded that it is possible that some cases of ill health could, on further investigation, be shown to be due to complex effects following exposure to pesticides.[178]

The Advisory Committee on Pesticides concluded that that assessment overstated the risks.[179] Georgina Downs described evidence amassed by the UK Pesticides Campaign and in the academic literature, including research since the 2005 Royal Commission report, on the effects of pesticides on people. The Campaign identified in particular what it sees as strong associations between pesticide use and a wide range of long-term chronic human illnesses.[180]

On neonicotinoids in particular, Georgina Downs told us that that particular type of pesticide was not the focus of the UK Pesticides Campaign.[181] Our agronomist witnesses had seen no link between human health and neonicotinoids:

I have been in the business now since 1976 and have dealt with a lot of farmers across a wide area. I am not aware of any direct or indirect link of the illness on a farm that has arisen as a result of farming operations, other than perhaps being run over by a tractor or something like that.[182]

Professor Vyvyan Howard of Ulster University told us that he had not identified any cases of human health effects specifically from the use of neonicotinoids.[183] Defra explained why such a link was unlikely:

The impacts of neonicotinoids on insects are largely the result of strong binding of the compounds to nicotinic receptors. The available data strongly suggests that the binding of neonicotinoids to mammalian nicotinic receptors is much weaker than to insect receptors. In addition, scientific studies show that neonicotinoids are not as potent in vertebrates (including humans) as they are in insects. Although this does not mean there are no effects in mammals, there is a higher margin between doses required to kill insects and doses of potential concern for people than is the case for some of the older insecticide active substances such as organophosphate compounds.[184]

The ACP added:

There is currently no evidence of harm to human health in either UK surveillance or the published literature following use of neonicotinoid insecticides in accordance with UK approvals. Given the very large margins of safety required in human risk assessment before an authorisation can be recommended, it is unlikely that use in accordance with the UK conditions of authorisation will result in any impacts on human health. However, as no experimental data are available on humans, in addition to the detailed risk assessment, the ACP also considers reports of suspected ill-health associated with pesticide exposure in the UK, and screens the published literature for reports of adverse health impacts that might be of relevance to UK pesticide use. ... None relate to approved use in the UK. Most seem to be reports of attempted suicide, mostly in developing nations. It is notable that the recovery from these events was generally within a matter of days with a relatively low level of mortality being reported. This contrasts to literature reports for some other insecticide classes which might be considered alternatives to neonicotinoids.[185]

The evidence and analysis provided by the ACP related mainly to potential acute effects rather than chronic effects. They told us that while monitoring had not identified reports of ill health in the UK associated with use of the neonicotinoid insecticides in accordance with their authorisations, those surveillance schemes focused on acute ill-health and were not designed to identify long term consequences of pesticide exposure.[186] ACP working groups are examining these issues, namely the Pesticides Adverse Health Effect Surveillance Scheme Working Group and the Bystander Risk Assessment Working Group.[187] This scrutiny is important, because there is some anxiety and concern which needs to be addressed in a timely fashion.

176   Ev 204 Back

177   Royal Commission on Environmental Pollution, Crop Spraying and the Health of Residents and Bystanders, September 2005, para 6.4 Back

178   Royal Commission on Environmental Pollution, Crop Spraying and the Health of Residents and Bystanders, September 2005, para 2.105 Back

179   Advisory Committee on Pesticides, "A commentary on the report published by the Royal Commission on Environmental Pollution in September 2005", December 2005, paras 3.39-3.45 Back

180   Ev 166-191, 241-250 Back

181   Q 543 Back

182   Q 565 Back

183   Q 475 Back

184   Ev 204 Back

185   Ev 220 Back

186   Ibid. Back

187   Ev 182-183 Back

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Prepared 5 April 2013