Human health concerns of GM agriculture

SGR Submission to the Scottish Parliamentary Health and Community Care Committee, November 2002


The precautionary principle should be invoked to halt the trials, for at least two reasons. The first of these, possible damage to health from GM pollen, is mentioned below. The second reason is the possibility of postponed repercussions on health if the soil in which the GM trial crops have been grown suffers adverse changes.

A warning has been issued1 by a group of nine experts on various aspects of soil ecology and related subjects, who foresee the danger that GM genes leaking out of crops into soil micro-organisms (a process that has been experimentally demonstrated) and transferred directly (‘horizontally’) into different species of micro-organisms (also demonstrated) may result in altered behaviour of the micro-organisms and consequent reduction in soil fertility:

‘1. The suggested mechanism might in the worst case cause irreparable, widespread, cumulative and persistent damage to soil fertility.

‘2. The genes causing the complication might in the worst case spread uncontrollably over vast areas.’

Because these processes are not yet well understood and cannot be quantified, this is a matter that should be urgently investigated. The questions that need to be addressed are:

a. How are the various soil micro-organisms affected by GM plants?

b. How does soil that has once grown GM crops affect future crops grown in it?

c. What effects would there be on the health of plants growing in that soil, and on animals and human beings eating those plants?


Causes for concern are that the GM field trials have been designed by the biotech companies and that they are not required to publish their data. A recent official report on the trials consisted of a derisory two sentences to the effect that no unexpected events had been found, except in one trial where sowing had been late. Challenged by lawyers at Friends of the Earth 2 about the inadequacy of such reporting, the Department of Environment, Food and Rural Affairs replied that they found the report satisfactory. Yet these trials are put forward to the public as scientific experiments designed to test the practical functioning of GM crops. Any other scientific experimenter, particularly one receiving large sums of government (i.e., public) money would be expected to submit an account of the experiment that was sufficiently detailed that independent scientists could examine the data and judge for themselves whether the conclusions are justified. As the Chardon Hearing showed, scientific reports commissioned by the biotechnology industry do not always stand up to such scrutiny.

The trials do not require monitoring the health of the agricultural workers or of the local population who are breathing or handling GM pollen. This should be done. For example, local doctors could report on illnesses, and these reports could be organised so as to focus on exposed farm workers, people who live in a small region centred on a GM farm and those who live downwind of a GM farm. These statistics should be compared with those for the population of those not affected by GM pollen.

That GM pollen should be a source of concern is confirmed by the now-famous laboratory studies3 carried out by Prof John Losey of Cornell University in which larvae of Monarch butterflies were fed on milkweed leaves with either untransformed (non-GM) Bt-maize pollen, in which case none of the larvae died, or GM pollen, in which case 44% died within 4 days. Whatever may be the situation for Monarch butterflies actually in the field, the experiment demonstrates the toxicity of this GM product to at least one animal species. Research has not been carried out to test for toxicity of other GM pollen.

Bees are another biological system that suffer from GM crops. ‘French researchers have discovered that some varieties of transgenic canola [oilseed rape] can harm bees, a farm's most effective pollinator, by destroying their natural ability to recognize flower smells.4

Very many interviews with farmers indicate strongly that GM feed is harmful to the health of animals, and it must be inferred that human health may also be adversely affected by the consumption of GM crops or GM-fed animals or animal products. These reports describe animals refusing to eat GM feed or, if forced to do so for lack of an alternative, of losing weight or otherwise failing to thrive. Some of the more recent ones are cited in a new report, Seeds of Doubt, issued by the Soil Association.5, 6

It is not only the GM crops themselves that have harmful potential; their cultivation usually requires the application of more herbicides than do non-GM varieties, as shown by experience in North America, contrary to the claims of the biotechnology industry. In addition, supplemental (and more toxic) herbicides may need to be applied. An analysis of US crops ‘revealed that the 10 per cent most heavily treated fields (predominantly RR [Roundup Ready] required at least 34 times more herbicide than the bottom 10 per cent (planted to non-GM crops).7 This means that farm workers are at greater risk from these chemicals. ‘A California study showed that [glyphosate] was the third most frequent cause of illness amongst agricultural workers.8 In the UK, supermarkets are eager to phase out the use of herbicides from their produce on grounds of problems they cause to human health. But ‘A single application [of herbicide, as advertised by the industry] has turned out to be impractical as it affected yields; instead farmers are applying herbicide several times in the pursuit of completely ‘clean’ fields, or applying older and more toxic herbicides in addition. New weed problems have emerged with HT [herbicide-tolerant] crops which are leading to a greater need for herbicides. These include the appearance of more weed species which are less affected by herbicides, weeds becoming resistant to herbicide and HT rape volunteer [self-sown] plants.9 The director of the Soil Association, Patrick Holden, was recently in the United States. He states:10 ‘A recent article in the Chicago Tribune said “The medical damage induced on the human intestinal tract and on human health by the ‘pesticides’ genetically contained in grains has become a silent pandemic.”’

Thus there should be concern about the herbicides used in the farm-scale trials and in the future, if the GM crops come into general cultivation.


Attempts to prevent cross-contamination of non-GM crops by GM ones are usually costly and restrictive. Even when such measures are in place, some contamination is very likely — in fact, the UK government has declared it to be inevitable.

Separation distances now set by Government regulations between GM crops and non-GM crops are grossly inadequate. Maize pollen, for example, although it is one of the largest grain pollens, can travel for hundreds of metres (and, at lower concentration, even many kilometres) and remain viable for as long as several days at cool temperatures.11 In field observations of outcrossing, one experiment12,13 measured a mean level of 0.32 percent at 500 m. Another set of observations 10,14 found 0.21 percent outcrossing at 805 m, and this level of concentration was not systematically decreasing with distance; it doubtless persisted to even greater distances. Research in progress15 on computer simulations of the experiments of Jones and Brooks and similar field trials reveals that patches of higher density of pollen can occur well beyond the distance at which the average amount of pollen has fallen to a given level. As expected, the distance over which pollen is carried is strongly dependent on the velocity of the wind.

The Soil Association has recently produced a major report, entitled Seeds of Doubt — North American farmers’ experiences of GM crops.16 It reveals that few of the claims made for GM crops by the biotechnology industry have been realised. A copy of this publication is being supplied separately to the Committee. The following quotations and references are extracted from this report.

Contamination of crops has reached disastrous proportions in Canada, where ‘contamination of the oilseed rape crop has reached such a level that most organic farmers in Saskatchewan, the province with the most organic farming, have given up growing rape.17 The ‘levels of background contamination are such that the whole organic sector feels that it is losing the ability to control contamination.’18

Contamination of seeds is likewise disastrous in North America. ‘The US organic certifier Farm Verified Organic has stated that GM contamination of maize, oilseed rape and soya is now so pervasive that they believe it is no longer possible for farmers in North America to source GM-free seed.19. The Canadian Seed Trade Association believes that all non-GM varieties of crops, where GM varieties are available, are contaminated with an average of one per cent GM seed.’20 . An organic farmer in Saskatchewan said, ‘We don’t grow canola … there were organic farmers growing it and most have dropped it as it is nearly impossible to get clean seed.21

The following excerpts from the current issue of the Soil Association’s magazine Living Earth 22 voice some of the grievances of farmers who choose non-GM agriculture:

‘“GM gives the farmer no room to play — it’s a pollutant,” said Canadian organic farmer Arnold Taylor …. Almost no more organic oilseed rape (canola) can be grown in Saskatchewan.

‘Arnold Taylor is president of Saskatchewan Organic Directorate, one of Canada’s leading organic industry groups. …

‘The group is seeking compensation for the destruction of the province’s organic oilseed rape market that resulted from the spread of Roundup Ready GM rape into organic varieties. It is also seeking an injunction to prevent Monsanto from introducing GM wheat into the state. … It is possible that the government may also be included in the suit because of its role in allowing the introduction of transgenic crops.’

North Dakotan organic farmer Theresa Podoll, executive director of the Northern Plains Sustainable Agriculture Society, said, ‘GM is like a cancer that has no boundaries. It’s like giving farmers a death sentence. Our organic producers are living a nightmare — please don't allow our nightmare to become yours.’

Dr Eva Novotny, Co-ordinator for GM Issues; Dr Stuart Parkinson, Chair


1, ‘Genetically Engineered Crops — A Threat to Soil Fertility?’, April 2001; summary in .


2 Written correspondence between DEFRA and Friends of the Earth, September 2002.

3 Nature, 1999, vol. 399, p. 214

4 Nikiforuk, Andrew, Oct. 1997, ‘The Bad Seed’, Canadian Business; as quoted in The Ecologist, vol. 28, No. 5, 1998, p.273.

5 Seeds of Doubt — North American farmers’ experiences of GM crops, report issued by the Soil Association, September 2002 (ISBN 0 905200 89 6).

6 ibid., pp.35-36.

7 Benbrook, C., 3 May 2001, AgBioTech InfoNet technical paper no. 4, ‘Troubled times amid commercial success for Roundup soybeans — Glyphosate efficacy is slipping and unstable transgene expression erodes plant defenses and yields’.

8 Seeds of Doubt, September 2002, p. 16.

9 Seeds of Doubt, p.17.

10 Living Earth, (winter 2002, p. 3; this is the Soil Association’s magazine.

11 Emberlin, J., Adams-Groom, B. and Tidmarsh, J., January 1999, A Report on the Dispersal of Maize Pollen, National Pollen Research Unit, University College, Worcester; commissioned by the Soil Association; p. 3, 11, 12.

12 Jones M. D., Brookes J.S., 1950, Oklahoma Agricultural Experimental Station Technical Bulletin No. 38.

13 Emberlin, J., Adams-Groom, B. and Tidmarsh, J., January 1999, A Report on the Dispersal of Maize Pollen, National Pollen Research Unit, University College, Worcester; commissioned by the Soil Association; p. 8.

14 Salamov, A.B., 1940, Sel. i. Sem, 3 (See also the preceding note, Jones and Brooks, 1950, p. 4)

15 Novotny, E. and Perdang, J., A Model for Pollen Transport by Wind, to be submitted for publication.

16 Seeds of Doubt — North American farmers’ experiences of GM crops, report issued by the Soil Association, September 2002 (ISBN 0 905200 89 6).

17 Seeds of Doubt, p. 27.

18 Survey of 10 US certifiers, Soil Association, June 2002; Seeds of Doubt, p. 32.

19, 30 April 2001, ‘GM pollution now pervasive’; Seeds of Doubt, p. 25 .

20 The Western Producer, 6 September 2001, ‘GM volunteer canola causes havoc’; Seeds of Doubt, p. 25.

21 Interview with Ian Cushon, 2 February 2002; Seeds of Doubt, p. 26.

22 Living Earth, winter 2002, pp 13.


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