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    No. 7 · Safe Food Campaign Newsletter ·July/August 2000


    Pesticides in food: why go organic?

    An analysis of New Zealand's latest Total Diet Survey by Alison White

    Pesticide Action Network NZ/Safe Food Campaign NZ Paper presented to the Organics 2020 Conference, Unitech, Auckland, 20 May 2000

    Executive summary

    The Ministry of Health assures us that "the pesticide residue levels found in [the latest Total Diet Survey] are unlikely to have any adverse health implications for the New Zealand population." Their conclusions are based on the assumption that pesticide levels below the Acceptable Daily Intake are safe. But this is based in turn on several unscientific assumptions, such as that we are exposed to only one chemical at a time. Results from the survey are furthermore questionable with the very small sample sizes being analysed: 86% of the 114 foods tested had a mere two composite samples analysed.

    Young children in New Zealand are getting about five times more pesticide residues than young American children. A sizable proportion of young NZ children could suffer from acute organophosphate poisoning from the residues in their food. The young child, aged 1­3 years old, takes in more pesticide residues than other age-sex groups, more than two and a half times more than men, for example.

    Fig. 1 Young child pesticide daily intake: comparison of US and NZ data

    3 organochlorides, 5 organophosphates and 5 fungicides analysed

    Source: NZ Total Diet Survey 1997/98, US Total Diet Survey 1986-91

    The percentage of total samples with pesticide residues is significantly greater than some other countries, for example, the UK and the US. Wine, grains, especially wheat, and meat are more likely to contain pesticide residues than other food groups. When ranked according to the number of pesticides in combination with the percentage containing residues, bread and wheat products, wine, fruit and salad vegetables come out worst.

    Recent findings concerning the endocrine disrupting potential of certain pesticides, eight of which are found in this survey, are a matter of grave concern, with disturbing consequences for the future of the individual, the family and society as a whole. A group of fungicides of concern, the most common of which is mancozeb, a known endocrine disruptor, continue to be used on a wide range of fruit and vegetables.

    Analysis of the latest Total Diet Survey reveals tragically unnecessary pesticide residues in the New Zealand diet. With co-operation from regulatory authorities and growers and farmers, New Zealand can become an organic nation by 2020.

    Young children at risk

    Young children in NZ are still getting about five times more pesticide residues than young American children. A similar calculation was made from data in the last survey, but this time comparing 13 pesticides. (See Figure 1) While organo-chlorine levels continue to fall, and are now similar to US levels of the late 80s, the levels for organophosphates and fungicides have both disturbingly risen to almost twice the level, expressed as estimated daily intake for young children in micrograms/kg bw/day.

    Young children are at special risk from acute poisoning from pesticide residues in food, especially from organophos-phates. In this total diet survey young children are estimated to consume almost three times as many organophosphate residues as men. (See Figure 2) US researchers from the National Research Council concluded that young children could suffer from acute poisoning from the residues in their food. They actually calculated that two-year-olds could exceed the Acceptable Daily Intake (ADI) (of chlorpyrifos) 4.1% of the time, basing their figures on just five pesticides and eight foods (NRC 1993).

    In Figure 1 we can see how the estimated daily intake of organophosphates in NZ young children is more than 20 times that of young US children. This means that a certain sizable proportion of NZ children could suffer from acute organophosphate poisoning. Common symptoms include tingling mouth, increased saliva, blurring of vision, sore stomach, nausea, diarrhoea. Two of the organophosphates found at high levels, pirimiphos methyl and chlorpyrifos methyl, are applied post harvest to grain in storage. Of concern is that young children have increased their intake of the organophosphate chlorpyrifos methyl more than elevenfold compared to the last total diet survey. This pesticide is now found in a wider range of foods (anything containing wheat) and at higher levels.

    Young NZ children consume an estimated 20 times more fungicide when five fungicides are compared to US data (chlorothalonil, dichloran, diphenyl-amine, iprodione and vinclozolin).

    Compared to other age-sex groups, young children (1­3 year olds) have the highest levels of pesticide residues in their diets. In Figure 2 it can be seen that they have an estimated daily intake of pesticides which is more than two and a half times more than men. This is mainly because children eat more food in proportion to their body weight than other groups, but also because they tend to eat more food like fruit which is highly sprayed.
    Interestingly, lacto-ovo-vegetarian females (dairy and egg eating), measured for the first time in this survey, consume about 50% more pesticide residues than other females. This seems to be due to the estimation that they eat more bread, more fruit and more of certain vegetables. This group does take in lower levels of DDT and other organochlorines due to their not eating meat.

    Fig. 2 Estimated pesticide daily intake

    Totals of 17 pesticides for age-sex groups

    Source: NZ Total Diet Survey 1997/98

    Which foods have more pesticide residues?

    Wine, grains and animals are more likely to contain pesticide residues than other food groups. Animals analysed included chicken, eggs, fish, meat as well as pizza. 79% of animal samples analysed had DDE, the persistent metabolite of DDT. The highest levels were found in butter, luncheon sausage and beef sausage

    DDT is the main contaminant of dairy products as well, especially ones with fat like butter, cheese, and whole milk. A comparison between American dairy products and New Zealand ones is startling: New Zealand's rate of contamination is so much higher: 68.2% as opposed to 3.4%.

    "The Dirty Dozen"

    Which foods is it especially good to avoid if non-organic and make an effort to buy organically? The 12 worst foods from the point of view of number of pesticides and percentage with pesticide residues were:

    • bread,
    • wine,
    • pears,
    • broccoli & cauliflower,
    • cabbage,
    • onions,
    • nectarines,
    • celery,
    • tomatoes,
    • cucumber,
    • apples,
    • sultanas/raisins.

    The ranking of the other foods on the dirty dozen list isn't necessarily very accurate because of the small number in each sample.

    Bread and wheat products are at the top of the list, with residues detected in 94.4% of 90 samples. Wheat products include bran cereal, biscuits, flour, noodles, spaghetti, wheatbix, cake, pizza, sausages, luncheon sausage, muesli, hamburger, meat pie and the batter around fish. The chances are you are also taking in organophosphate or insecticide residues most of the time you eat something with flour in it. Most of these residues result from the post harvest application of a fumigant on the stored grain (chlorpyrifos methyl, pirimiphos-methyl, piperonyl butoxide, fenitrothion,). The level of these insecticides does not seem to have decreased overall since the Total Diet Survey in 1990/91, even though NZ's residues are much higher than either the UK or US. The US had residues in 27% of wheat and wheat products, in contrast to New Zealand's 94%, for example! Other countries are increasingly using non-pesticide means of storage for their grain, for example, cold storage or carbon dioxide.

    Wine is second on the list, with all 12 samples having iprodione, a fungicide in them. The good news is that the levels of vinclozolin, a known endocrine disruptor, have fallen. (It has just recently been deregistered.) The bad news is that grape growers seem to be substituting another fungicide, using more iprodione instead. Overall, levels of iprodione in food have increased 80% since the last Total Diet Survey. Iprodione, a chemical cousin to vinclozolin, can cause cancer.

    Close contenders for the dirty dozen list were lettuce, dairy products, meat and potatoes.

    Health effects of these pesticides

    Many of the pesticides found as residues in our food have been found in independent studies to have serious long term effects including hormonal disruption, cancer, immune system suppression, nervous system damage, genetic damage and birth defects.

    Children are at special risk with any substance capable of causing cancer and nervous system damage. A number of animal studies have shown that animals are at greater risk of developing cancer if exposure began in infancy rather than later in life. Of 14 carcinogens reviewed by the US Natural Resources Defense Council, the young were more susceptible to 12 (Whyatt 1989). The reason for such susceptibility may be linked with rapid cell division entailed in development and growth. Also children have more of their lives still to live during which exposure and carcinogenic action may occur.

    The young are especially susceptible to the acute effects of organophosphate insecticides.

    Endocrine disruption

    Recent research has brought to light another class of adverse effects from various pesticides and other chemicals. Several pesticides (as well as some widely used industrial chemicals) can disrupt the body's endocrine or hormonal system ­ so crucial in growth and development. These endocrine disruptors can mimic or disrupt the normal functions of hormones, and tamper with this delicately balanced signaling system in the body, which governs a range of functions and developmental processes.

    Though their effects in human beings are still being debated, the evidence is mounting. From wildlife and animal studies in laboratories, there is growing concern that these endocrine disruptors can cause developmental, reproductive, behavioural, immunological and physiological changes.

    Particularly worrisome is the threat that endocrine disruptors pose on the unborn. When acting on a developing foetus at critical periods, they can cause lasting damage at minute doses, which were previously not thought to be harmful. Theo Colborn, researcher and author of the book "Our Stolen Future", expressed: "We are neutering the population; we are making females more masculine and males more feminine."

    Eight pesticides found in this survey are known endocrine disruptors: DDT, dicofol, endosulfan, chlorpyrifos, di-methoate, fenitrothion, mancozeb (as dithiocarbamates) and vinclozolin. There are various other pesticides structurally related to these which are suspect.

    The dithiocarbamates are a group of fungicides including mancozeb, metiram, zineb and ziram which have a metabolite called ethylene thiourea (ETU). This breakdown product is a known endocrine disruptor, carcinogen, mutagen and teratogen, and can concentrate upon processing and heating. In other words, if you cook a vegetable which has been sprayed with mancozeb (the most common), you will be increasing the amount of the dangerous metabolite.

    Over 60% of the 138 samples of fruit and vegetables analysed for dithio-carbamates in the latest total diet survey contained them. The 17 fruit and vegetables ranked in order according to occurrence and mean concentration are:

      broccoli, cabbage, tomato, celery, lettuce, onions, cucumber, apples, oranges, mushrooms, potatoes, courgettes, kumara, nectarines, pears, capsicum and kiwifruit.


    The young, those who suffer from chronic illness and anyone who eats more bread, fruit and vegetables than average are more at risk both short term and long term from pesticide residues in their diet. For these people particularly, it is important to increase the amount of organic food eaten, especially those foods which are heavily sprayed.
    In general, if you are trying to reduce pesticide residues in your diet, especially seek out organic bread, fruit and salad vegetables, meat and butter. It is especially important for pregnant women and women who may conceive to eat organic wheat, fruit, vegetables, meat, cheese and butter. Ideally, a woman would detoxify before conceiving (pesticides are passed through the placenta and breast milk).

    We can help protect ourselves from a toxic environment by eating organic food, and by demanding a benign system of agriculture and an economy and infrastructure that does not depend on pouring pollutants into the atmosphere, rivers and seas.SF

  1. A full copy of Alison's "Total Diet Survey Analysis" can be obtained by sending a s.a.e. to the Safe Food Campaign.

    July 2000

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