Long term, low-level exposure to these widely used pesticides have a significant impact on brain function and memory

Organophosphate pesticides harm memory, say scientists

5 December, 2012

By Staff Writer
Natural Health News

Natural Health News — Here’s yet another good argument in favour of organic farming: exposure to organophosphate pesticides can cause lasting damage to your memory, according to new research.

Investigators from University College London (UCL) and the Open University analysed at data from 14 studies involving 1,600 participants to get a clear overview of literature on the subject.

The results showed that low-level exposure to organophosphate pesticides (OPs) produces lasting damage to the nervous system and brain. The findings showed that, in particular, memory and information processing speeds are more impacted by exposure to organophosphate pesticides – which are used to prevent people from contracting disease and to combat starvation – than other cognitive functions such as language.

This review, published in the journal Critical Reviews in Toxicology, is the first to attempt a quantitative evaluation of the existing data, say the scientists.

“The analysis reveals that the majority of well-designed studies undertaken over the last 20 years find a significant association between low-level exposure to organophosphates and impaired cognitive function,” says lead author Dr Sarah Mackenzie Ross of UCL’s Clinical, Educational & Health Psychology department.

Derived from World War II nerve gas agents, organophosphate pesticides are the most widely used insecticides in the world. They are used extensively in agriculture, by the military and also for domestic purposes.

According to the World Health Organization (WHO) organophosphate pesticides are one of the most hazardous pesticides to vertebrate animals, responsible for many cases of poisoning worldwide.

The toxic effects of high level poisoning are well established but the possibility that long-term low-level exposure to OPs in doses below that causing acute toxicity causes ill health is controversial.

“In the UK a number of occupational groups have expressed concern that their health has been affected by exposure to organophosphates,” explains Dr Virginia Harrison (Open University), co-author of the study.

These include sheep farmers, who between 1988 and 1991 were required to dip sheep yearly in pesticide formulations containing OPs. Between 1985 and 1998 more than 600 reports of ill health following exposure to sheep dip were received by a government adverse reaction surveillance scheme.

Other groups affected include Gulf War Veterans, who were exposed to pesticides on a daily basis during their tour of duty to protect them from pests such as sand flies, mosquitoes and fleas which carry infectious diseases and airline pilots and cabin crew, who can be exposed to organophosphates in engine oil.

The researchers hope their findings will be of interest to those who believe their health has been affected by exposure to OPs and to Government advisory committees and departments who are currently reviewing the neurotoxicity of low level exposure to OPs.