Eco-warriors have long reported the damage that pesticides have caused the environment. Just earlier this year, US biologists reported that pesticides could be threatening the survival of Salmon in the Pacific. But for many of us in the UK, we carry on eating food grown with the help of pesticides and ignore the claims of the green brigade.
However, researchers from a London University have found that it might not just be the environment that is being harmed by pesticides. These chemicals could be responsible for some human deaths too – suicides in fact, brought on by exposure to a certain type of pesticides.
Okay, so the pesticides at the centre of the study (organophosphate agricultural pesticides) are banned in Western nations, but these chemicals are sadly still used in lower income countries such as China and the findings are certainly worrying. Results have shown that these pesticides can be absorbed even through low-grade exposure by the skin and lungs.
Scientists from King’s College London have found the first evidence through an epidemiological study suggesting a link between pesticide exposure and suicidal thoughts. Their work, which was recently published by the World Health Organisation, found that in China people who were exposed to higher level of certain pesticides were more likely to experience suicidal thoughts.
Preparing to use pesticides on crops. Image courtesy of of Roy Bateman, Wikipedia Commons. Used here under Creative Commons Attribution ShareAlike 3.0 License
Over 9000 residents in Zhejiang province were sampled in the study carried out by KCL in conjunction with the Tongde Hospital of Zhejiang Province. Participants were asked both about the storage of pesticides at their homes and whether they had ever considered suicide within the 2 years before their interview. To detect the presence of any mental disorders the Chinese version of the 12-item General Health Questionnaire was administered and trained psychiatric nurses carried out the interviews.
Alarmingly the researchers found that those people who stored pesticides at home, and therefore suffered more exposure, were more likely to report contemplating suicide. Easy access to the pesticides was associated with thoughts on suicide and the geographical regions with the highest prevalence of pesticides (the rural areas) also had the highest levels of suicidal thoughts in their populations.
Although this study made no attempt to quantify the actual pesticide exposure, the findings are certainly interesting with regard to health policies. Pesticides are frequently used during suicide attempts; in fact, pesticide ingestion was involved in 62% of China suicides between 1996 and 2000. But now it seems they might also be subconsciously linked with suicidal thoughts.
Dr Robert Stewart, from KCL’s Institute of Psychiatry, believes these findings are a cause for concern: “Our research findings that suggest that higher exposure to these chemicals might actually increase the risk of suicidal thoughts provides further support for calls for tighter international restrictions on agricultural pesticide availability and use.”
With these organophosphates so readily available in countries like China more work is needed to firstly understand the causal mechanisms which lead to increased suicidal thoughts and also how best to intervene in this situation to ensure public health is safeguarded. Hopefully, this work and further research may help convince even people in the UK that chemical pesticides are more harmful than first thought and should be eliminated from food production.