It all started with the disappearance of the bees. Around 10 years ago, naturalists were among the first to catalogue the disappearance of honeybee colonies, then gardeners noticed there were fewer bees in the garden and, by 2006, the phenomenon had a name-colony collapse disorder (CCD). By last year a third of the managed honeybee colonies across the US had died out.
What was causing this growing eco-disaster? Scientists thought it was the combination of several factors: the honeybee's greatest enemy, the parasitic mite Varroa destructor, was spreading more deadly viruses into colonies; bacterial disease was infecting the colonies; the bees were suffering from nutritional deficiencies; and the pesticides we spray on plants and crops were causing DNA damage and affecting the bees' ability to navigate.
Of all these reasons, scientists kept coming back to the last one, and study after study was finding an association between pesticides and bee death. Finally, last month (July) a Europe-wide ban was imposed on all pesticides that contained neonicotinoids, a class of chemicals that seem to have the most devastating effect on bees. The ban will last for two years and will give scientists time to investigate whether colonies start to revive.
Although the disappearance of bees is a potential catastrophe, it's ironic that it's this that has finally forced governments into action when for years they have been handed studies demonstrating the harm that pesticides do to human health.
The most recent was a meta-analysis (a review of many published reports) of more than a hundred studies showing that people who are in regular contact with pesticides and solvents-like gardeners and farm workers-are far more likely to develop Parkinson's, the neurological disease. Depending on their level of exposure, some people were 80 per cent more likely to suffer from the disorder.1
Although it's the most recent evidence, it's not the most alarming. Over the years, studies have shown that the weed killers and insecticides we spray on our farm crops, rose bushes, parks and verges can cause cancer-especially leukaemia in children, brain tumours and prostate cancer-as well as birth defects and arterial damage.
Many pesticides are endocrine disruptors-they interfere with normal hormone production-which can cause a range of chronic conditions especially in developing fetuses, children and people who are more exposed to these toxins, such as farm workers and those living near farms.
Close to home
Pesticide exposure is not a problem limited to farming communities and those living in remote rural locations. Our homes and schools also harbour these pollutants. The pesticides we spray on our potted plants and furnishings are creating an environmental hazard every bit as dangerous as that faced by the farm worker and rural dweller.
We are also using more powerful insecticides on our plants in the garden-one Amazon reviewer described Monsanto's brand-leading herbicide Roundup as "the Darth Vader of weed killers". The spray settles on our clothes and shoes, which is another way they are getting into our homes. Britons spray around 4,306 tonnes of pesticide in their homes each year, while Americans use 34.5 million kg (76 million lb) on their household plants and furnishings.2
Easy does it
Getting approval for a pesticide or insecticide is a relatively inexpensive procedure. Unless a product contains one of the banned active substances on a very short list of only a dozen-most of which were withdrawn because they were carcinogenic (cancer-causing)-it is likely to gain approval.
Even compounds that have a dubious safety record-certainly enough to stop a pharmaceutical application in its tracks-are likely to be approved. The licensing of a pesticide that contains only approved compounds can cost as little as lb20,000 through the UK licensing process for use on Britain's farms, parks and gardens. One that contains a new active ingredient can be approved for around lb200,000 compared with approval costs ranging from lb20 million to lb140 million for a drug.
Not surprisingly, regulators have been swamped by applications. Pesticide manufacturers are taking full advantage of an overloaded EU approvals regime, and 39 pesticides-including the highly toxic 2,4-D and diquat-that have not been assessed for their safety or impact on human health under new safety regulations are today being used throughout Europe. This regulatory 'free ride' is expected to last until 2015, at which time the regulators hope to have caught up with the backlog.
Bring in the experts
In assessing the safety of compounds and setting dosages that are supposedly not a health hazard, regulators depend on evidence from expert groups, but environmental research group Earth Open Source (EOS) says the process is being abused. Data are being manipulated and pesticide manufacturers are funding supposedly 'independent' research groups that command enormous influence among regulators, it claims.
In one example concerning the approval of glyphosate, one of many chemical compounds found in Monsanto's Roundup pesticide, EOS has uncovered a trail of cover-up, denial and massaging of data to hide the fact that it causes birth defects. According to EOS, industry researchers were aware of glyphosate's effects as early as the 1980s, but those initial findings were in laboratory animals given high doses. But by 1993, industry researchers discovered that glyphosate had the same effects at low doses, a conclusion also drawn by German government scientists in 1998, but which they minimized by redefining birth defects as "variations". A year later the EU Commission's expert scientific review panel also knew-and the EU Commission itself was aware of it in 2002 when it approved glyphosate's use in Europe.
The public was not told of the true risks posed by glyphosate, and the compound is not likely to be reviewed under the new, more stringent safety checks until 2030.3
The Argentine link
Glyphosate's link to birth defects may have gone unnoticed had it not been for a massive biochemical experiment in Argentina in 1999. Genetically modified (GM) Roundup Ready soybeans were planted on 19 million hectares-around half of Argentina's cultivated land-and sprayed with 200 million litres of Roundup.
In 2002, the year the EU renewed glyphosate's safety licence, doctors started to report an epidemic of health effects in areas surrounding the experimental farms. Common problems included birth defects, infertility, stillbirths, miscarriages and cancers. Livestock and food crops died, and local streams were filled with dead fish.4
By 2009, Professor Andr'es Carrasco from the University of Buenos Aires Medical School, and lead researcher of Argentina's National Council for Scientific and Technical Research, had 'gone public' about his discovery that glyphosate and Roundup caused birth defects in laboratory animals even at very low doses. He published his findings a year later.5
Speaking at a conference at the European Parliament (GMO-Free Regions Conference, European Parliament, September 16-18, 2010), Carrasco said it was common for women living in a GM soy region to experience up to five miscarriages in a row.
On countering Carrasco, Monsanto claimed that its Roundup product had been declared safe under Good Laboratory Practice (GLP) rules. GLP rules were established by the Organisation for Economic Cooperation and Development (OECD), a body that seeks to promote international trade. These rules lay down how an experiment should be carried out with the aim of increasing traceability and accountability. They are not a measure or guarantee of good science, yet they are used by industry and regulators to dismiss the worrying findings of independent non-industry studies, like Carrasco's, that are not done according to GLP rules. Independent studies go through a system of journal peer review and publication which, though far from perfect, is a far more rigorous process than GLP rules.
Other attempts to silence Carrasco have been more sinister. Four representatives of Argentina's crop protection trade association CASAFE reportedly tried to raid his laboratory, and he was also the focus of an orchestrated violent attack in which three people were seriously injured when he went to speak in La Leonesa, an agricultural town in Argentina.
Carrasco escaped injury by locking himself in his car.6
Months after Carrasco's findings were published in 2010, residents in Santa Fe province, one of Argentina's GM soy-producing regions, won a court order banning the use of Roundup sprays near homes. Viviana Peralta, the housewife who spearheaded the lawsuit, said she and her family needed hospital care after fields near her home had been sprayed. Her newborn baby had turned blue, she said, "When I saw my baby like that, I said, 'Enough. This cannot go on.'"7
Even worse reactions were being reported in La Leonesa, the town where Carrasco was attacked. Birth defects had increased fourfold in the region around the town between 2000, when pesticide spraying began, and 2009, and the rate of childhood cancers tripled over the same period. A state commission report identified glyphosate as a major cause.8
Cancer and more
Pesticides don't only cause birth defects and miscarriages. According to a range of independent studies, they also cause cancer, Parkinson's disease, peripheral arterial disease, neurodegenerative diseases like Alzheimer's and asthma.
Cancer in children.Cases of cancer caused by pesticides seem to be especially prevalent in children possibly because of their lower body weight and exposure while in the womb and from breast milk. Leukaemia appears to affect children whose mother was exposed to pesticides in the prenatal period, while brain cancers seem to happen more in children whose father was exposed. The risk for both cancers is significant, say researchers.9
Several studies have found that children are also more susceptible to pesticides used in the home and garden. One review, which analyzed data collected between 1950 and 2009, found a direct correlation between childhood leukaemia and pesticides and insecticides used in the home and garden, and sometimes with herbicides as well.10
Cancer in adults.Adults are not immune to the toxic effects of pesticides, especially if they have been regularly exposed to them through their work. Orchard workers, who are in daily contact with pesticides, are more likely to develop brain cancer. One study of 432 patients with brain tumours discovered that 389 of them had worked in an orchard.11 Prostate cancer is also more prevalent in homes close to farms in areas of intensive agriculture. A study in California's Central Valley estimated that the risk rises by up to 1.64 times in areas with intensive farming.12 Even those who use pesticides in their homes on their potted plants double their risk of brain tumours, a French study found.13
Parkinson's disease.Pesticides such as ziram, maneb and paraquat increase the risk of Parkinson's by up to three times, say researchers who analyzed the homes and workplaces of 362 Parkinson's patients living in central California. The risk was worse at workplaces-usually farm buildings-and when a person was exposed to all three pesticides, but a greater risk was still seen in homes, albeit to a lesser extent.14 Even for those who don't work on farms, pesticides in the air we breathe can be a cause of a range of neurodegenerative diseases, including Parkinson's, Alzheimer's and multiple sclerosis, Spanish researchers have discovered. In a study of 17,429 patients with neurodegenerative diseases, rates were far higher in areas where there was more intensive use of pesticides.15
Peripheral arterial diseasePesticides play a significant role in the development of peripheral arterial disease (PAD), especially in obese people. In one study levels of five organochlorine pesticides were measured in 2,032 patients, and the risk was considerably increased for three of them (trans-nonachlor, oxychlordane and dieldrin). Pesticides did not increase PAD risk in those who were not obese.16
Asthma.Pesticides can not only increase the chances of developing asthma, but also bring on an attack in sufferers by increasing bronchial hyperresponsiveness, say researchers. The main culprit seems to be household pesticides delivered by spray cans and aerosols.17
Mental development.Pesticides can also affect mental development and reasoning skills, as researchers discovered when they analyzed parental exposures to pesticides in 404 children born in New York City between 1998 and 2002. Problems with reasoning and problem-solving continued into childhood and particularly affected those whose parents had the highest levels of pesticides in their blood.18
Follow the money
The pesticide industry is very big business. It generates around $45 billion in global sales every year, and this figure is expected to rise by 2.9 per cent each year until 2014.19
To protect these vast sales-many of which are made to developing countries, where environmental and safety controls are poor-the chemicals industry ensures it is part of the regulatory process through initiatives such as the GLP and ILSI. Any worrying results can be 'lost' or diminished by changing a study's definitions, as happened with glyphosate.
The influence of ILSI
The International Life Sciences Institute (ILSI) is a highly influential 'scientific' group that also happens to be almost entirely funded by multinational pesticide, chemical, GM (genetically modified) seed and food companies like Monsanto, Unilever, Nestl'e and DuPont.
ILSI experts work closely with European Food Safety Authority (EFSA) regulators in shaping and redesigning risk-assessment procedures for its benefactors' products. EFSA regulators are also associated with ILSI affiliates by publishing papers in scientific journals. However, these papers almost never report on the safety of chemicals but instead are continually proposing changes to those risk assessment procedures.1
The World Health Organization (WHO) has been a bit more cautious in choosing its friends. In 2006 it barred ILSI from participating in the setting up of microbiological and chemical standards for food and water because of its industry funding. The US Natural Resources Defense Council is also distrustful of ILSI. Its senior scientist Jennifer Sass has said in a letter to the WHO that ILSI "has demonstrated a history of putting the interests of its exclusively corporate membership ahead of science and health concerns".2
1. Europe's pesticide and food safety regulators: Who do they work for? Earth Open Source (online), 2011
Even without the interference of biased groups, safety trials are generally inadequate, relying almost exclusively on very limited laboratory tests involving experimental animals.
Once they're used on our farms, gardens, parks and in our homes, the harmful effects of pesticides on our health are insidious. They are often slow to build up over time, so no one can be absolutely certain that these chemicals are the culprits.
Only when a massive biochemical experiment takes place, as happened in Argentina, do we see the true harmful potential of the toxins we breathe in and eat every day.
The pesticides industry is a major contributor to the epidemic of chronic diseases that began early in the last century. Many pesticide manufacturers have some corporate affiliation to a pharmaceutical company and together they invariably put profits before people. In this, they are aided by regulators whom we pay to look after our health.
Most of the life-threatening diseases mentioned in the main article are the result of sustained and long-term exposure to pesticides. But an acute reaction-one that strikes within minutes or hours after pesticide exposure-is also possible. Here's a list of the more common symptoms:
Skin and eye irritation
Chills or fever
Numbness, tingling sensations
Changes in heart rhythm (arrhythmia)
Nausea, vomiting, diarrhoea.
Life without pesticides
Environmentalists are urging farmers to adopt the principles of Integrated Pest Management (IPM), which encourages the use of less toxic products, and adopting practices that harness processes that are more natural.
The ladybird (ladybug) is a natural enemy to many insects, for example, and encouraging its spread provides a non-toxic antidote.
There's plenty you can do around your garden, too:
o Beer-and stale beer in particular-is a great way to keep slugs and snails under control.
o Boric acid can be dusted on cracks and crevices.
o Neem oil is a natural pest deterrent, but always remember to wash all vegetables first before eating as the oil shouldn't be consumed.
o Essential oils make a safe and effective spray for plants and flowers in your garden.
o Marigolds are natural magnets for pests. If you're growing fruit and veg, plant the flowers nearby to keep pests away.
The best and the worst
Washing fruit and vegetables before we eat them isn't always enough to get rid of all pesticide residues. Some are more contaminated than others and most are covered in residues of multiple pesticides. Many pesticides are systemic-they aren't just on the food but in it, having been absorbed into the plant as it grows-so no amount of washing can remove those poisons.
Here are the best and worst according to their levels of pesticide.
% with residues
% with multiple residues
Fruits with little or no pesticide residues
Fruits with the most pesticide residues
Vegetables with little or no pesticide residues
Corn on the cob
Vegetables with the most pesticide residues
Beans in pod
Peas in pod
Natural Resources Defense Council (www.nrdc.org)
Beyond Pesticides (www.beyondpesticides.org)
The Healthy House (www.healthy-house.co.uk)
The Pure H20 company (www.pureh2o.co.uk)
1. Neurology, 2013; 80: 2035-41
2. Pediatr Clin North Am, 2001; 48: 1185-98, ix
3. Roundup and birth defects: Is the public being kept in the dark? Earth Open Source (online), June 2011; J Environ Anal Toxicol, 2012; S: 4
4. New Scientist, 2004; 182: 40-3
5. Chem Res Toxicol, 2010; 23: 1586-95
8. Comision Provincial de Invesigacion de Contaminantes del Agua, 2010; in English at http://www.gmwatch.eu/files/Chaco_Government_Report_English.pdf
9. Occup Environ Med, 2011; 68: 694-702
10. Cien Saude Colet, 2011; 16: 1915-31
11. Indian J Med Paediatr Oncol, 2010; 31: 110-20
12. Am J Epidemiol, 2011; 173: 1280-8
13. Occup Environ Med, 2007; 64: 509-14
14. Eur J Epidemiol, 2011; 26: 547-55
15. Toxicol Appl Pharmacol, 2011; 256: 379-85
16. Atherosclerosis, 2011; 218: 200-6
17. Curr Opin Allergy Clin Immunol, 2011; 11: 90-6
18. Environ Health Perspect, 2011; 119: 1182-8