Sep
29
2010

The poison blood of mutated plants is in your water! Or something.

Not real: Not even close. So don't go thinking that what's happening in this picture is real.
Not real: Not even close. So don't go thinking that what's happening in this picture is real.Courtesy Paranoid
Check this out, my little ducks: Scientists have genetically modified corn, so that it produces a deadly toxin. And that toxin is now appearing in waterways across the country.

O.M.G.

But you should also check this out, my little chickpeas: That toxin (called “BT toxin”) is also naturally produced by the soil-dwelling bacteria Bacillus thuringiensis, which is already found sort of all over the place, including on leaves of plants. Also, all evidence indicates that while the toxin is deadly to certain insect species, it is utterly harmless to vertebrates (including people). Which is good, because most of the corn planted in this country has been engineered to produce the toxin in its leaves and stems,a nd that’s the way it’s been for years. And that may be good itself, because the bug killing toxin the plants produce can allow farmers to use a lot less synthetic, broad-spectrum pesticides (broad spectrum pesticides kill off lots of different bugs, instead of a specific few).

And consider this, my little Turkish delights: Those manufactured pesticides definitely run off fields into ground and surface water. See? So it seems like pointing out that the chemicals produced by the plants themselves also find their way into the water is a little bit of a “well, duh,” situation.

But science doesn’t run on “duhs,” my little Faberge eggs, it runs on empirically confirming or disproving explanations and ideas, whether or not they initially seem obvious. Because the toxin was contained in the leaves and stalks of the plants, it seemed less likely to get washed away in the same way sprayed-on pesticides usually are. But it got washed away nonetheless.

It got washed away, my little candy apples, but not in the same way—the toxin was present in streams 6 months after harvest, inside the floating detritus from cornfields. That is, the toxin was inside the bits of leaves and stems that had washed off cornfields, and into streams.

That doesn’t mean that the BT toxin is harmless, my little floral prints, but nor does it mean that it’s necessarily harmful. BT toxin appears to be a pretty environmentally safe pesticide on land, but that doesn’t say much about effects it could have in an aquatic ecosystem. It could be that the presence of BT toxin in the water is still much safer than the alternative (chemical pesticides), or it could be that it will have far reaching effects—Corn Belt streams end up in the Mississippi and Missouri River basins, and eventually in the Gulf of Mexico, after all.

So, my little rabbits’ feet, we should try not to be all, “well, duh,” or to get too freaked out about the whole situation. Before that happens, scientists will have to figure out what environmental effects the BT toxin has, and how those compare to other pesticide run-off, and how each might balance against our need for crops that haven’t been eaten by bugs.

Scientific American’s brief article on the presence of BT toxin in streams also brings up the issue of no-till farming. Scraps from corn fields ending up in streams is very common, apparently, but the SA article suggests that no-till farming might be increasing the amount of that kind of organic matter that end up in the water. No-till farming is a method of farming where the soil isn’t regularly plowed or turned over, and scraps from crops (crop residue) are left on the field after harvesting to increase soil quality. No-till can increase the amount of water in the soil and decrease erosion, but the remaining crop residue might end up in nearby streams to a greater extent.

If this is the case, my little supernovas, it makes me wonder if the crop residue from no-till fields is worse for the water than soil washed off of tilled fields (and whatever washed away with that soil).

I also wonder what becomes of the toxins in BT-producing crops when the crop residue is not left on the field. Because, of course, that stuff doesn’t just disappear. Crop residue can be burned on the field, or processed into ethanol fuel, burned in a power plant to generate electricity, or maybe dumped into the ocean. So, my little chitterlings, even without bringing our thirst for fuel and electricity into the mix, what happens to BT toxin in those scenarios? Probably nothing, for the most part, but, again, we don’t want to invest too much time in saying “duh.”

It’s all very complicated. But you knew that already, didn’t you, my little safety goggles?

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Your Comments, Thoughts, Questions, Ideas

JGordon's picture
JGordon says:

Whoops. I don't know if I ever linked to this: the report the Scientific American article was based on. So there it is.

posted on Wed, 09/29/2010 - 2:50pm
Shana's picture
Shana says:

I wonder, too, how no-till impacts sediment loads in the rivers. On the Mississippi, sediments have already been cut in half since the 1800s-ish thanks to dams and the like, and this is part of the problem with inundation in the delta. If fields aren't eroding, does that make it even worse?

posted on Wed, 09/29/2010 - 4:25pm
JGordon's picture
JGordon says:

I wouldn't think so, but I don't know much about it. I imagine that no-till fields are quite a bit closer to a "natural" rate of erosion. Even so, I bet they still lose a lot more top soil to wind and rain than wooded areas or uncultivated fields.

And... (now that I'm thinking out loud), I wonder how much of a difference this amount of sediment makes if it couldn't get to the delta in the first place. I mean, if agriculture (and erosion) has increased over all in the last couple hundred years, but the sediment load has gone way down, I suppose the dams are a much more significant part of the problem.

posted on Wed, 09/29/2010 - 4:43pm

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