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Bite the dust, the pesticides in a healthy eater's shopping basket
Joanna Blythman
Guardian Unlimited
10th May 2003
If you follow the Food Standards Agency's advice on healthy eating, you'll be picking up a lot of beneficial nutrients but unfortunately your intake of pesticide residues will be significant too. About a third of all the food and 40% of all the fruit and vegetables we eat contains pesticide residues.
The government's Pesticides Residue Committee says they are usually "at very low levels" and "do not present a concern for consumer health". But other experts are not so sanguine. They point out that tests look at pesticides individually but that our knowledge of the "cocktail effect" of different contaminants is very limited.
According to Dr Vyvyan Howard, a leading toxicologist at the University of Liverpool who has studied the effects of pesticide combinations on unborn children, "Pregnant women are now exposed to completely novel molecules that their grandmothers were not. Quite a number of these are capable of hormone disruption and various scientists' work shows that it takes only extremely low doses to cause effects." For example, the cocktail effect could be related to the decreased age of puberty in girls, which is known to have implications for breast cancer later. Incidence of breast cancer has risen dramatically since the 1960s. "This could be due to the imprinting of chemical disrupters in the womb," Dr Howard says. He recommends buying organic.
In 2001, government tests found pesticide residues in 1,148 samples of conventionally grown food. Only six organic samples contained residues. Most supermarkets say they are working to reduce pesticide use. M&S and the Co-op have taken the lead: M&S is committed to phasing out the 79 most hazardous pesticides, with 60 already banned; the Co-op has banned 20 and restricted 30 more.
Lettuce
Leafy vegetables are particularly likely to contain residues. Lettuce is no exception: half contain residues. The most recent survey of "winter lettuces", (grown in glasshouses to permit a year-round supply) revealed that 18% contained residues above the "maximum residue limit" while 6% contained "non-approved" (illegally used) pesticides. "What is most worrying is that in two cases where residue levels were considered by the Pesticide Safety Directorate to be possible safety risks, the growers had simply followed label instructions from the pesticide company," says Sandra Bell of Friends of the Earth. Illegally used pesticides found included insecticide dimethoate, from a group of organophosphorous chemicals that are toxic to the nervous system. Dimethoate is listed by the EU as a "suspected hormone disrupter".
Oranges
An orange might give you a healthy shot of antioxidant vitamin C, flavonoids and fibre but 2002 government results show that 100% of soft citrus contain residues. Pesticides used include 2,4-D , one of a number of endocrine disrupting chemicals. Research links EDCs in humans to declining sperm counts, breast and testicular cancer. The Royal Society says that "human exposure to EDCs (especially during pregnancy), should be minimised on grounds of prudence".
Bananas
Popular with children and often recommended as a healthy snack and good source of potassium, more than half of bananas tested in 2002 contained residues. One of the pesticides commonly identified is imazilil, a post-harvest fungicide described by the US Environmental Protection Agency as "likely to be carcinogenic [cancer-causing] in humans". Tropical fruit and vegetables seem to be particularly likely to contain residues.
Apples
In 2001, tests found that 72% of apples had residues. Latest tests suggest that may be improving, with residues now cropping up in 27%. One pesticide found is chlorpyrifos, one of the world's most used insecticides, an organophosphate which kills insects by disrupting their nervous system. The US government restricted its use in 2000 to protect children's health. The UK government has not yet introduced restrictions. UK growers say they have to use more pesticides on apples than they would like to meet retailers' cosmetic appearance requirements.
Pears
Government tests carried out in 2002 show that 63% of pears contain residues. Pears have a history of pesticide contamination. Since 1995, tests have shown illegal use of the growth regulator, chlormequat, which is used on pears purely to produce a uniform size of fruit. Folpet, listed by the US Environmental Protection Agency as a "probable human carcinogen", was also found above safety levels in Portuguese pears.
Stone fruit
Rich in vitamin C and beta-carotene, stone fruit has much to recommend it but it does seem residue-prone. In 2001 government tests an average 50% of peaches and nectarines contained residues. One of the most common pesticides found in stone fruit is the broad spectrum fungicide, iprodione, a suspected endocrine disrupter or "gender-bending" chemical. It is also used to grow potatoes, brassicas, lettuce and tomatoes. In 2002 tests, 63% of apricots had pesticide residues. The organophosphate chlorpyrifos (see apples) was found over legal limits in apricots, as was the hormone disrupter, carbendazim.
Potatoes
The latest government results for 2002 showed residues in about half of maincrop and new potatoes. These include the insecticide aldicarb, a nerve poison, classified by the World Health Organisation as "extremely hazardous". In a special survey in 1999, a sample of microwaved potatoes exceeded the government safety limit for toddlers. This means it could cause "immediate health effects" in any toddler who ate it. One of what is known internationally as the "dirty dozen" pesticides, the EU agreed to ban aldicarb if a majority of member states voted in favour of a ban. The UK supported its retention.
Oily fish
While it is a rich source of omega-three fatty acids and vitamin D, 97% of fresh salmon studied in 2001 contained residues of organochlorine residues such as lindane, a known hormone disrupter strongly linked to breast cancer, and DDT, which is banned in the UK. Both pesticides are known to have particularly long-persistence and bioaccumulate in fatty tissue. The pesticide residue committee says that residues in salmon are extremely low and "not of concern for human health".
In 2001, one in every five farmed salmon and trout also contained traces of malachite green, a synthetic fabric dye that kills parasites. Suspected of causing genetic mutations that can lead to malignant tumours in humans, it was banned on US fish farms in 1991. In 2002, it was banned in the UK following an inspection by EU vets who reported that, although it had no market authorisation in the UK, "it is commonly used in salmon and trout production, with the full knowledge of the competent authorities". Since then government scientists have detected it in four samples of Scottish salmon.
Cereals and bread
Cereal bars, though generally high in sugar, are promoted as a healthy breakfast "on the move". In 2001, an average 67% of cereal bars and 29% of breakfast cereals contained residues. In the same year 38% of bread contained residues. In 2002, more tests carried out on part-baked bread found residues in 66%. If you follow advice to eat wholemeal products, your exposure to residues will be higher than if you eat less healthy refined white products. Studies suggest that wholegrain products may be two to fives times more likely to have residues than refined, processed grains. Pesticides commonly detected in cereals and bread include chlormequat (see pears) and the organophosphate pirimiphos-methyl.
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