I can give you two cases. Last year, the health inspection service discovered large quantities of poison in both red grapes and spinach, from pesticide use. On the grapes, the poison wasn't just on the outside, but the prolonged use of pesticides had infected the ground and the poison had entered the grapes that way. We have very strict checks on this, but never the less one or two supermarkets kept selling them as long as a year after. This is partly why the use of pests' natural enemies (e.g. lady bugs against lice) has become a very popular alternative to pesticides. Though funnily enough this has other ramifications too - for instance Japanese lady bugs have been very popular for this, but escape and turn out to do quite well in our natural habitat, so that they threaten to supplant the native species. Since the native species is a little more friendly to humans (the multi-coloured Asian ones tend to build large nests inside houses, for one), they are now looking to use that one instead.
Poison builds up in your body in several ways and has many long term effects. Research of mother milk has shown that pesticides and many other sorts of pollution build up in women's breasts for instance and can even be traced back into mother milk. This has reached such an extent that the advantages of mother milk (transference of bacterial resistance, good hormones and such) are canceled out by this pollution and articifially produced baby milk is now considered at least as healthy as mother milk, because although it doesn't hold the advantages of mother's milk, it also doesn't hold the disadvantages.
Intestinal cancer is another result from extended exposure to pesticides. This was proven, ironically, by research of South-Americans who primarily eat beans. Beans are slightly poisonous by nature and it was shown that several forms of colon cancer were much more common around age 40 and upwards.
Incidentally, I don't believe in Soy-beans either - it shares certain aspects with growth hormone rife meat (use of which is prohibited here btw, but not for instance in Belgium), in that soy-beans contain a proteine that is so similar to the female hormone oestrogen that the body reacts to it almost identically.
The girl I cited (this was in Australia, if I remember correctly) was just an example of how excessive and out of proportion it can get, but most of the dangers are long-term effects like cancer.
As far as GM goes, I know there's a trade-off between development and economic interest, but the light-bulb example isn't one of indecision, conservatism, or excessive socialism. It is an example of the great impact that inventions can have on society, and just clear evidence that care is in order. So are things like SARS, or Creutzfeld-Jakob, the latter of which could have been incredibly devastating because the dramatic effects become known so long after the infection - just recently it was determined that more people than previously thought are vulnerable to the (pretty horrible!) condition, and it's still very possible that we'll see 10.000 or more deaths as a result. Even then, it doesn't take a lot of imagination to realise that it could have been much, much worse.
I just read today about a GM experiment with a tree (apple tree I think) that was better resistent to bugs, but while testing it as also modified so it wouldn't produce any flowers, so it couldn't infect the environment with its spores. It's a small effort to take a little bit more care, and economic advantage doesn't make everything right. If I shoot you in the back and steal your wallet after all there's also a clear economic advantage (well, if you have any money that is
).
- as I no longer have access to BIDS or WoS, I can't pull any papers to check on this, but the theory was still "active" in 1997 when I was required to write about it for my BSc. You didn't ask for cast iron causes though - only cases where pesticide use was linked to health problems.
