MedTerms.com defines an herbicide as a chemical product that controls, inhibits or destroys plants, including weeds and grass. It adds that herbicides also kill other plants that you might accidentally spray with them. Herbicides are popular among many gardeners, who find them convenient, effective and easy to use. However, scientific studies have shown some of the chemicals to be harmful to humans, animals and the environment.
Dr. Tyrone Hayes, a professor of biology at the Berkeley campus of University of California, has conducted research on the common herbicide chemical called Atrazine and reports that it can cause human cancers, such as that of the prostate and the breast. Although Atrazine has been banned for use in the European countries, yard maintenance workers and homeowners continue to use this chemical in the United States.
Dr. Tyrone Hayes' research on Atrazine also uncovered reproductive problems in humans, including low fertility rates among people who work in the manufacturing of herbicides containing Atrazine. Another chemical is Glyphosate, an ingredient in the common herbicide Roundup. It can be deadly to human placental cells, according to a 2005 study that Professor Gilles-Eric Seralini of France's University of Caen conducted. This chemical, he reported, causes late, spontaneous abortions in livestock that graze in areas where it has been used and eat plants sprayed with it.
In 2008, Dr. Tyrone Hayes spoke at a lecture series in Kansas and implicated Atrazine in causing the "feminization" of male frogs, both in the wild and in the laboratory. He also tested rodents, and found that they also turned into hermaphrodites, like the frogs affected by this herbicide's runoff into their ponds and other living areas. Atrazine, according to Dr. Hayes, lowers the ability of immune systems to ward off disease. He has also concluded, based on tissue and cell studies, that Atrazine's feminizing effects can also occur with humans who are exposed to large quantities of this chemical over time.
Several other chemicals that herbicides contain have been shown to cause problems and diseases of the digestive organs. For example, Alachlor can harm the liver, kidneys or spleen. Endothall, which is used around sugar beets, potatoes and spinach, causes problems for the stomach and intestines, according to the Web site "History of Water Filters."