Stories tagged pesticides

Sep
29
2010

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?

Apr
22
2009

Big wheel keep on turnin': Modern agriculture produces more food on less space than traditional forms.
Big wheel keep on turnin': Modern agriculture produces more food on less space than traditional forms.Courtesy Andrew Stawarz

Continuing our string of counter-intuitive ecological findings, today we read an article which argues that factory farms are good for the environment. It turns out that people need food. And the 6-billion-plus people on the planet today need a LOT of food. So much so, that 38% of the Earth’s land surface is dedicated to farming. That’s a lot. But, thanks to innovations like pest-resistant foods, artificial fertilizers, pesticides and herbicides, and expanding irrigation, it’s less than half the area that would be necessary under more traditional farming methods.

(Genetically modified crops are particularly beneficial, as they require fewer chemicals, less fertilizer and help reduce erosion.)

This is not to say that big farms are not without their environmental impact. But that impact is a lot less than it would have been without these innovations. So, on this Earth Day, let us give thanks to the farmers for feeding us, and for doing it so efficiently.

Most insecticides work by killing bugs before they get the chance to grow and reproduce, but a new research study suggests that when it comes to mosquitos and malaria, this strategy might be part of the problem. Killing young mosquitoes increases the selective pressure on the population to develop resistance to pesticides. This means that any given pesticide will stop working shortly after it is introduced, making it harder to fight the disease, which is caused by parasites and spread by mosquitoes. By killing the mosquitoes when they are older, but before they are old enough to spread Malaria, scientists believe they can prolong the effectiveness of pesticides and save lives. This article explains more about their ideas. Learn more about malaria and share your thoughts on Science Buzz.

May
27
2007

Rachel Carson, inspiration for the modern environmental movement: Photo from US Fish & Wildlife Service
Rachel Carson, inspiration for the modern environmental movement: Photo from US Fish & Wildlife Service

Today is the 100th anniversary of the birth of Rachel Carson, whom many credit as the inspiration for the modern environmental movement. Her 1962 book Silent Spring warned the world of the dangers of environmental degradation, especially due to the overuse of chemical pesticides. The book stirred millions of people worldwide to take action. In the United States, we saw the passage of the Clean Air Act, the Endangered Species Act, and the establishment of the Environmental Protection Agency – all the result of the movement Carson inspired.

Today, our air and water are cleaner thanks to these actions, and dangerous chemicals are more closely regulated. But some people are re-evaluating Carson’s legacy, especially with regards to the pesticide DDT. Carson explained how insects absorbed the poisonous chemical. Birds which ate enough insects often died themselves, or would have trouble hatching eggs. Carson promoted restricting the use of DDT.

However, some of her followers went further, pushing for a total ban of DDT in many countries. Unfortunately, DDT is extremely effective at killing mosquitoes that spread malaria – a disease that kills some one million people each year. Responsible, limited use of DDT could save millions of lives.

(Science Buzz has discussed malaria here and here,and the possible effects of preventative measures such as mosquito nets, drugs, and genetic engineering.)

Carson’s legacy reminds us not only of the importance of protecting our environment, but also that one person can have a tremendous impact. It also reminds us that even the best ideas can have unintended consequences, and any major changes need to be undertaken in a balanced, rational and flexible manner.