A new study from the GenOk Centre for Biosafety in Tromso show a reduced fitness of Daphnia magna fed on Bt maize MON810. Daphnias fed on MON810 had a higher mortality rate, less females reached sexual maturation, and the overall egg production was lower compared to D. magna fed isogenic maize. Since this reduced fitness after feeding on Bt maize coincided with an earlier onset of reproduction, the scientists concluded a toxic effect rather than a lower nutritional value of the GM-maize.
After adverse effects of Bt maize on caddis flies last year, this is no the second study showing possible adverse effects of Bt maize on aquatic organisms. Meanwhile the environmental risk assessment of GM crops in the EU does not include aquatic ecosystems.
Bøhn T, Primicerio R, Hessen DO & Traavik T (2008): Reduced Fitness of Daphnia magna Fed a Bt-Transgenic Maize Variety. Archives of Environmental Contamination and Toxicology, DOI 10.1007/s00244-008-9150-5.

Im folgenden Report werden einige mögliche Auswirkungen des Bt-Maises auf die Umwelt dargestellt. Selbst nach mehr als 10 Jahren kommerziellen Anbaus von Bt-Mais gibt es nur wenige Studien zur Risikoabschätzung. Zugleich werfen die meisten dieser Studien mehr neue Fragen auf, als sie beantworten.