Effects of Herbicides

Herbicides are better known as weed killers and have been in widespread agricultural use since the 1930s. Early herbicides did not discriminate; they would kill any plant species they touched and were little more than poison. However, science has gotten more sophisticated. Combined with the genetic modification of food crops, scientists have come up with herbicides that are genetically targeted to attack the cells of weeds with no negative effect on crops. Herbicides have helped to significantly increase crop yields worldwide.

History

• Many common herbicides, especially in third-world countries, are older formulas that were developed before the focus on genetic research. These herbicides were created simply by testing a bunch of different chemicals to see which ones worked in killing the weed, then finding the derivative that gave the best results. Many of these older formulas have been banned for use in European countries and in North America since little effort was spent during development to gauge the long-term effect of these products. Yet there are still some common herbicides in use that have shown significant negative health and environmental impact in both the medium and long term.

Atrazine

• Atrazine, commonly used on corn, has been shown to cause reproductive defects in frogs that are exposed to it in runoff. The male frogs in the study, which was conducted by Tyrone Hayes from the University of California at Berkeley, developed both male and female sexual organs and had lower levels of testosterone than the females. These effects were found in levels 40 times lower than that allowed in drinking water and hundreds less than that found in agricultural runoff. Studies like this one have raised concern about the effect atrazine has on fetuses, infants and prepubescent children. While legal in the U.S., it is currently banned in France, Germany, Italy, Sweden and Norway.

Glufosinate

• Glufosinate is an herbicide used with genetically modified plants. It is known to cause convulsions in humans as well as birth defects to children born of a father who has been exposed to it. There have been numerous studies with rats that display an even wider range of birth defects resulting from exposure. Glufosinate has the side effect of killing many of the beneficial insects in the area, increasing the population of harmful insects and the use of pesticides to combat them. There is concern that because the chemical does not harm the crop, farmers tend to overuse the product and cause higher levels than necessary to be released into the environment.

Glyphosate

• Glyphosate, the active ingredient in Roundup brand weed killer, makes people sick. It is a widely reported cause of illness in California agricultural workers. Symptoms include eye and skin irritation, headaches, nausea and heart palpitations. Studies show glyphosate also has a detrimental effect on surrounding plant and soil health.

Roundup

• A 1998 study, published in Environmental and Molecular Mutagenesis, found that an unidentified ingredient in Roundup triggered genetic damage in exposed mice's livers and kidneys. Because of the manufacturer's patent, which prevents researchers from accessing the full list of ingredients and their concentrations, the actual chemical responsible remains unknown.