Fri March 12, 2010
Popular Herbicide Under Scrutiny
By Angela Hatton
Murray, KY – The weather is starting to warm and farmers in western Kentucky are preparing for the spring growing season. Part of that preparation is ordering chemicals to spray on the fields. Atrazine is a weed-killer corn and sorghum farmers have used widely for over fifty years. Continuing scientific studies question atrazine's impact on animal life. A recent study suggests atrazine changes hormones in male frogs, turning 1 in 10 into egg-producing females. In October of last year, the Environmental Protection Agency launched a re-evaluation of atrazine and its effects on humans. But atrazine is well-entrenched in the U-S agricultural system, and many farmers see the studies as an attack on their livelihood.
In Kentucky, between 75 and 80 percent of farmers use atrazine on their corn, and nearly the same use it on sorghum. University of Kentucky Weed Specialist Doctor Jim Martin says there are three simple reasons for that.
"I call it the three E's. Atrazine's extremely effective, it's economical, and it's easy to use, and if you meet those three criteria you're on a gold mine. You've got something that's gonna be used by lots of growers."
Martin says atrazine kills half of the twenty common weeds. It costs between 3 and 6 dollars an acre and all farmers have to do is spray it on their field when they plant their seed. He says the active ingredients in atrazine usually won't harm corn and sorghum. As for the land, water, and wildlife, the main atrazine manufacturer Syngenta claims over six thousand studies have been done.
"There's really no other herbicide that has been studied as extensively as atrazine."
Most of those studies cluster around 1990, when the EPA put strictures on where atrazine could be used. The atrazine companies commissioned the studies to measure safe zones and safe contamination levels.
"Y'know don't use it in these areas where it's prone. Don't use it certain number of feet close to, um, rivers or reservoirs or likewise with sinkholes there are what we call buffer zones."
Some scientists question the validity of any study paid for by a weed-killer manufacturer. Many are concerned with more than zones. Murray State University Associate Biology Professor Claire Fuller studies toxins. Her most recent project is atrazine and how it affects insects.
"I think that's one of the common misconceptions, that herbicides are only going to affect the plants. But in fact, we're so similar, plants and animals, that what affects the plants is very likely going to affect the animals."
Fuller says before she started her study, she looked at the studies that were already out there. She says many exist, but most only looked at certain groups of animals and focused on atrazine concentrations that would kill.
"What I think is lacking is does it harm them in a way that could affect their reproduction and y'know, just harm the environment and the community of organisms."
Fuller says when looking at what affect atrazine might have on humans, the need is for long-term studies.
"One thing you have to take into account is these animals are very short lived. So they're exposed to more than we would be, but they're also exposed over a shorter period of time. Whereas with us, if we are getting it we're exposing ourselves for much longer periods, so it's hard to tell what's happening."
The EPA is conducting a scientific review of atrazine's effects on humans, and advisory panel members meet next in April. Some corn growers' organizations are worried about review. In a written statement, Kentucky Corn Growers Association President Phil McCoun says "strong efforts are underway to remove this valuable herbicide. . . ." Organic farmer Brad Lowe admits that without chemicals, he can't go large-scale. Large scale farmers depend on herbicides, pesticides, and fungicides to make their annual yields. Lowe says organic farming is more labor intensive, but he prefers the small farm model.
"Y'know the small farms are getting swallowed up by large corporate enterprises. I don't know if you can call them farms. They're like agra-business parcels."
UK Weed Specialist Jim Martin says expectations have changed in the past twenty years. He says land owners who lease acres to farmers equate weed-free fields with quality.
"When they go by and they look at their fields and say you know what, this guy's doing me a good job. I'm going to lease with him again next year. That helps the grower. But you take a year when all a sudden and there's lot of weeds out there. Now the rules have changed and the land owner, he's thinkin' you know what, I'm not impressed with this guy. I think I'll go down to the next farmer down the road and lease my ground to him."
A report on the EPA's review is set for the end of this year. Groups on both sides of the issue are eager to hear the results. But so far, there's no indication how far EPA officials will go to restrict atrazine.