Glyphosate is the active ingredient in many non-selective plant herbicides for use in gardens and cropfields. It is sold in products with names like Round Up, Rodeo and PondMaster. It is considered a general use pesticide and, although technically an organophosphate compound, its molecular structure does not cause disruption of the nervous system in mammals if absorbed (unlike some types of dangerous chemicals that are restricted-use). Nonetheless, a warning label accompanies products with glyphosate to promote proper ethical use of the chemical.
When glyphosate is sprayed in liquid solution onto plant leaves, flowers or stems, it is absorbed into the tissues and eventually transported throughout the entire plant via the vascular system. According to the California Department of Pesticide Regulation, glyphosate inhibits plant growth by disrupting production of growth hormones and other amino acids. Effects of the chemical on plants starts with wilting of foliage, then yellowing of the same. Lastly, the above-ground plant parts die and turn brown, and the roots die. Depending on weather conditions, chemical dosage, and thickness of any protective cuticle on plant leaves, the effects on plants begin to be visible within four days and result in plant death seven to 14 days later.
According to the Extension Toxicology Network, glyphosate is slightly toxic to animals. Waterfowl are at most risk to the chemical, but overall glyphosate is not readily absorbed by animals via their skin or gastrointestinal tracts. Great dosages are required for negative consequences, and the dosage recommended on pesticide labels in the United States do not pose threats if followed ethically. Moreover, freshwater fish, rodents, songbirds and insects are not harmed by glyphosate. The chemical molecules bind to soil particles well, do not leach into soil and will naturally degrade in no more than 14 days.
As with animals, glyphosate does not pose dire harm to humans if bare skin comes in contact with solutions made according to product label directions. If taken internally, the chemical passes through humans (and other mammals) intact and expelled in their organic waste. According to the Extension Toxicology Network, there is little potential for glyphosate accumulate in tissues like fat or muscle. The California Department of Pesticide Regulation comments that the U.S. Environmental Protection Agency in 1988 concluded that there is little evidence or data to suggest glyphosate that occurs in drinking water poses a risk for cancer. Therefore, it is in Group D in the EPA's list of cancer risk materials.