and we can not trace what harm the GM food to us,and have a little knowledge about the potential problems which the GM food have.and the safeguards are now just on the assumption ,not in evidence. For example, when the things go wrong or have a cross-contamination occur ,, at that time ,however ,we can not "recall"it.
At the same time, GM food also have an effect on the environment .Intensive agriculture has already led to a significant decline in farmland plants, insects and birds, "although the specific role of herbicides on this process was less clear," the report says. (the labelling GM food, see bibliography 7).
The impact of GM crops which were herbicide tolerant - allowing all other weed plants to be killed - was still being assessed by a government study and the results were eagerly awaited this autumn. However, the report says: "This poses perhaps the most serious potential harm arising from these particular crops." The scientists were also concerned about how farmers would apply this technology under real conditions. In theory, farmers might use less herbicide, less often, allowing weeds to survive longer, but in practice they might use the technology to wipe out all weeds, further reducing the volume of wild plant seed in agricultural areas, and reducing biodiversity further. Another potential danger was the development of crops that were tolerant of drought, heat, salt or other soil conditions which made it impossible to grow crops at present. "Such crops could become more successful as weeds, and there could be economic pressure to cultivate areas with wildlife and conservation value.
For some crops, avoiding contamination may be relatively easy, but for others almost impossible. Separation distances between crops and whether it was possible for both GM and conventional crops to co-exist would be a political decision. Transfer of genes from engineered crops to weeds could produce problem plants into the environment, the report says.
