May 14, 2007

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Sale of MON810 maize restricted

New risks to the environment? Confusion surrounds BVL notification.

The sale of seed of the genetically modified maize variety MON810 is prohibited in Germany with immediate effect until such time as the producer, Monsanto, submits an up-to-date monitoring plan. This does not however affect maize already planted in this year’s cropping period. The official explanation for this decision is causing confusion: It states that new findings indicate that the cultivation of MON810 maize could harm the environment. While anti-genetic engineering associations called on agriculture minister Seehofer to ban MON810 maize immediately, scientists were puzzled by the sudden U-turn in the safety assessment.

On 27 April 2007 the Federal Office of Consumer Protection and Food Safety (BVL) sent a formal notification to agro-biotech company Monsanto. In it, the BVL, the authority responsible for genetic engineering in Germany, orders an immediate sales ban on seed from genetically modified MON810 maize. Sales may resume only when the company submits a suitable monitoring plan for monitoring undesirable effects on the environment and identifying them in good time. The notification lists nine points for checking, including what happens to the Bt toxin produced by MON810 maize in the soil, impacts on non-target organisms and long-term effects on biodiversity.

MON810 maize has been authorised in the EU since 1998 and is the only GM plant currently grown commercially in Germany and many other EU countries. At the beginning of February 2007, farmers – particularly those in the eastern German states – had registered a total cultivation area of 3700 hectares in the site register, although some of these were later withdrawn.

At the time the BVL sent the notification with the sales ban, most farmers had already sown their MON810 seed. “Seed already delivered to farmers or sown is not affected by this ruling,” the BVL clarified in a press release. And there are no plans to restrict use of the harvest for food and feed. This means that the ruling will not make any difference to farmers planting fields with MON810 maize this year. Cultivation is still permitted with no restrictions, Monsanto explained. The company also claimed it was already carrying out a monitoring programme “that fully complies with the future requirements.”

“New and additional scientific findings”

What triggered heated public discussion was the explanation given for the measures. In its explanatory statement, the BVL cited “new and additional scientific findings” that “provide justified grounds for assuming that the cultivation of MON810 represents a danger to the environment.” A large number of scientific studies are listed to justify this claim. The response was immediate.

• On the one hand, organisations against genetic engineering, and organic farming associations called on agriculture minister Seehofer to draw the conclusions from the BVL explanation and ban the cultivation of MON810 immediately.
• On the other hand, scientists in particular were puzzled that the authority responsible in Germany is now assuming that there is a change in the environmental safety assessment of MON810.

As recently as the end of 2006, the expert panel of the European Food Safety Authority (EFSA) looked in a detailed statement at the national MON810 ban in Greece, which is based largely on the same scientific sources as the explanatory statement for the sales ban in Germany. The EFSA experts examined all the current scientific data on MON810 and the Bt toxin produced in the plant and found no indications to justify revising the cultivation authorisation for MON810.

What is most surprising though is that for many years the German government has been promoting a biological safety research programme. Numerous projects and field trials spanning several years have investigated, among other things, potential environmental effects of Bt maize – mostly MON810. However, the results, which have since been published in scientific journals, have not been taken into account in the BVL explanation.

This mentions two areas in which “new and additional information” give grounds for a re-evaluation of the environmental risks posed by MON810: “risks for the soil” and “risks for non-target organisms”, i.e. all organisms apart from the targeted pest that come into contact with Bt maize directly or indirectly.

Predatory insects: Ingest Bt toxin with their prey, but no clear indications of risk

According to the explanation of the BVL notification, it is only more recent research that has shown “that Bt toxin reaches higher links of the food chain and to what extent.” By “higher links” they mean e.g. predatory insects that ingest Bt toxin indirectly with their prey. An evaluation of numerous laboratory investigations (Lövei & Arpaia 2005) showed that negative effects were measured in 41 per cent of the parameters investigated for predatory insects, including lifespan, development time and breeding rate.

• However, on closer inspection, it appears that the majority of the 44 studies evaluated were not dealing with Bt toxin but with other proteins used to combat pests, such as protease inhibitors and lectins (insect resistance). Many of the studies did not investigate the Bt toxin used in MON810 (Cry1Ab), but looked instead at other variants – and not just in Bt maize, but also in insect-resistant potatoes, cotton and rice.
• Many studies do in fact show that Bt toxin ends up in organisms in the higher levels of the food chain. But there appear to be hardly any clear scientific findings that demonstrate a harmful effect of the Bt toxin. Another review (Romeis et al. 2006), which is also mentioned in the BVL explanatory statement, comes to the conclusion that negative effects of the Bt toxin on predatory insects are observed only when the prey in question is fed with Bt toxin and is sensitive to it. Only in cases where the prey is obviously weakened by the Bt toxin does this have a negative effect on their predators, as is to be expected. There is much to suggest that Bt toxin does not in general have any direct toxic effect on the predatory insects.
• As part of the BMBF-funded biological safety research programme, numerous field studies have been conducted to investigate potential effects on non-target organisms. The elaborate experiment design meant that it was possible to make statistically reliable statements. In total, around a million organisms were collected, identified and assessed. The few Bt effects that were detected were slight and much smaller than the effects of conventional insecticide treatments.

Butterflies: Only a few trials with MON810 maize

The Bt toxin produced in MON810 is found to have “clearly harmful effects on caterpillars”, according to the BVL explanation. However, almost all the studies used to support this statement relate to Bt176, a different insect-resistant maize. However, this variety has not been sold for a long time now, since it has an unnecessarily high Bt concentration in its pollen, 150-250 times higher than that found in MON810.

Only one of the studies listed (Diveley et al. 2004) actually relates to MON810. It looks at potential negative effects on the Monarch butterfly, a popular butterfly in North America. And in fact, it was found that one-quarter fewer butterflies reach the larval stage if they are exposed to the Bt toxin in high doses. Although negative effects were observed in individual caterpillars, the effects on the Monarch population as a whole are limited. No more than 2.4 per cent of the Monarch population in the American corn belt was thought to be affected. In view of natural fluctuations, e.g. as a result of climate change, the study authors felt that the effects of MON810 cultivation were negligible. In Germany comparable research carried out over three consecutive years found no harmful effects even on the most sensitive species of butterfly.

Bt toxin in the soil: persistence, but no accumulation

The effect and persistence of Bt toxin in the soil is “currently unclear,” so the BVL claims in its notification, but “holds considerable potential for ecological consequences.” Bt toxin can enter the soil through plant remains or secretions in the root area.

The behaviour of Bt toxins from plants is, however, basically no different from that of conventional Bt preparations that are used as biological pesticides. Regardless of the form of application, the active Bt substance can be detected in the soil for several months. After the cultivation of Bt plants, traces of Bt toxin can persist in the soil in plant remains for a whole growing season – this too was shown by a BMBF-funded biosafety research project. But the concentrations are so small that no harmful effects can be detected on soil life. This means that there are no indications that the Bt toxin could accumulate in the soil and so reach toxicologically relevant concentrations.