Five fears about GM corn | Science| In-depth reporting on science and technology | DW | 14.04.2014
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Five fears about GM corn

The cultivation of genetically modified corn is being debated throughout the EU. There are big fears about possible health and environmental dangers. Are the worries warranted or unfounded?

Health risks, environmental damage and placards featuring corn cobs grimacing menacingly: the discussion about genetic engineering is ridden above all with anxieties. In a poll from environmental organization Greenpeace, the majority of German consumers strongly opposed the cultivation of the genetically modified (GM) corn variety 1507. This maize has been approved to be grown Europe-wide. DW gets to the bottom of the possible anxieties which regularly arise when it comes to this controversial crop.

No, it doesn't. One of the biggest concerns about the introduction of genetically modified corn is that consuming it could cause illness. But agricultural scientist Friedhelm Taube asserts that, to his knowledge "there are no scientific studies which have documented a danger to health." Furthermore, the vast majority of the corn under the German Farmers' Association ("Deutscher Bauernverband") would be produced as feed for dairy cows; the remainder would be used for the generation of energy in biogas plants. Therefore, the corn cultivated on a large-scale would not end up on the plates of consumers.

What about the cows' milk, though? The TUM Technical University in Munich ("Technische Universität München") proved in 2008 that the genetically modified material in corn could be excluded from being passed on to consumers through milk. In a two-year study, cattle were fed with the genetically modified maize MON810, which like the currently-discussed GM corn variety 1507 has the gene of the naturally occurring bacteria bacillus thuringensis (Bt) introduced into its genetic makeup. The researchers detected neither illness in the cows, nor could they find traces of the genetically-modified material from the corn in the cows' milk.

Yes, it could be dangerous for vermin and other animals. The European Food Safety Authority (EFSA) examined the maize variety 1507 amongst others to see whether the protection from insects, for which it had been genetically modified, also endangered other animals apart from those which posed a danger to corn. The EU body based its statement on expert advice received from member states, for example the German Federal Office of Consumer Protection and Food Safety (BVL). According to that, the pollen of the maize had the highest concentrations of the self-produced insecticide. This successfully killed the damaging European corn borer, but also a related butterfly, the wax moth, which poses no threat to the maize. Greenpeace accused the EFSA of not adequately investigating the negative consequences of the Bt-protein on other types of insects.

For bees, researchers currently see no threat from the GM maize. Animal ecologists from the University of Würzburg have probed the possible effects of Bt-maize pollen on honeybees and their larvae. They could not determine any negative consequences. However, this pollen can end up in the honey which the bees produce. Honey which has been gathered from the flowers of genetically modified plants is no longer allowed to be marketed as organic.

There's no definite answer yet. Corn is a cultivated plant and grows mainly in sunny and warm regions of the world. It originated from Mexico. In Germany, maize, no matter whether it is genetically modified or not, cannot by itself spread out from the land on which it is cultivated. There are no plants native to Germany with which the maize plants can successfully cross-breed. Furthermore, the corn is not able to survive a German winter.

However, agricultural ecologist Rüdiger Graß from the University of Kassel gives some food for thought: "If like this year we have a very mild winter, or the maize becomes ploughed into the earth, the plants could germinate afresh."

All plants have an effect on their environment and the soil, and here genetically modified maize is neither an exception nor a larger danger, adds Graß. "Maize pollen, which is blown into streams and rivers, does however serve as basic nourishment for smaller animals." All possible impacts of the GM corn have not yet been conclusively examined.

Possibly. In Germany about 2.5 million hectares of maize will be cultivated, that covers about a fifth of the country's total arable land. Europe-wide there are more than 500 maize varieties and hybrids. So, is it possible to prevent genetically modified maize from mixing with other maize types?

Wild pigs, bees and other animals could have a hand in mixing up maize varieties, says plant researcher Rüdiger Graß, who believes, however, that the flight of pollen is the biggest contamination risk: "In areas of law relating to genetic modification technology there is talk about different minimum distances between the fields. At the same time, no-one can seriously answer how much of a gap is safe." Whether maize pollen can travel for 100 or 1000 meters, the agricultural scientist says, depends among other things on the wind strength and air temperature - and has nothing to do with the type of maize.

That depends on your point of view. "A healthy skepticism is always appropriate," thinks Friedhelm Taube from the University of Kiel in response to German consumers' reservations about genetically modified maize. Taube has also been engaged in the ethical elements of what's called "green genetic engineering". He adds that "at the same time, it is important the whole debate is focused on the facts again." In the agricultural sector, unreliable publications from environmental protection organizations present more belief than real scientific expertise.

The worries of consumers should be taken seriously. Emotional aspects certainly seem to play a major role in the debate about genetically modified maize. That's why a rational discussion is a basic prerequisite for a realistic consideration of all the pros and cons.

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