non-target organism

In the beginning everything was simple. Bt maize was supposed to be just on the field, and nothing else would be affected: No organism that wasn't on the field, no organisms that would prey on maize pests. But over the years things became more complicated and now it's common knowledge that parts of the Bt plants make it off the field themselves, that predators can be affected indirectly in the food web. And still the question whether the field crop maize could also water organisms seems to be one step too far for most risk assessments.

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.

The report presented here shows the many ways Bt maize impacts the environment. Even after more then a decade of commercial growing of Bt maize crops, the risk assessment studies are still few and most of them tend to raise more open questions than solving concerns.

Rosi-Marshal et al. (2007) just published a long overdue study about whether Bt plant residues got into headwaters during or after cultivation, and whether the Bt-toxin would have adverse effects on water insects like caddies flies, close relatives to butterflies. In both cases the answer was yes. This laboratory study gives enough indication to at least include water insects in the monitoring of Bt crops.

Scientists in the UK put 16 lines of three different GM potatoes under a range of stress situations and then studied the quantities of two main groups of secondary, toxic metabolites. They found significant differences. An argument why it is necessary to study GM crops under realistic conditions.