Home gardeners and large commercial enterprises both use herbicides to control unwanted plants, commonly called weeds. Herbicides are generally easy to apply and their manufacturers claim that they are safe to use if their safety instructions are followed. However, people who work with herbicides, and receive large exposures of the chemicals they contain, can develop certain diseases. And the plants and animals these products contact can also have adverse reactions.
Types of Herbicides and How They Work
When you use an herbicide, typically you spray it on unwanted plants. Several chemicals are used in commercial herbicides. Glyphosate is found in common products, such as Roundup. Atrazine is also found in commercial herbicides. Alachlor and endothall are two other chemicals contained in some herbicide products. A systemic herbicide that contains the chemical picloram disrupts the cell growth of plants, leading to their death. Purdue University states that this chemical injures plant growth when it moves into the roots.
Effects on Plants
Herbicides do not discriminate when it comes to the kinds of plants they kill: they will kill any plant they contact. The instructions on herbicide packages include cautions and warnings: one of these is to avoid using such products on windy days. If a weed is growing next to a plant you value, consider pulling it by hand rather than using an herbicide, because your favorite herb or vegetable might die if the herbicide penetrates the soil where its roots are growing.
Effects on Animals
Atrazine has been implicated in harming frogs in areas where this herbicide is used. Dr. Tyrone Hayes, a professor of biology at the University of California reported in 2008 that atrazine reduces animals' immune functions and has caused "feminization" of male frogs. Glyphosate has caused miscarriages in livestock that graze in sprayed areas, according to the journal "Environmental Health Perspectives" in March 2005.
Effects on Humans
Humans who have high exposure to herbicides have fallen ill and died, according to the Chemical Watch Factsheet, which reported that nine of 56 Japanese nationals who consumed glyphosate died. The findings implicated an inert ingredient in Roundup, polyoxyethyleneamine (POEA). In 1999 the American Cancer Society reported that people who have frequent contact with glyphosate are nearly three times as likely to come down with non-Hodgkin lymphoma than are those who have no exposure to this chemical. Researchers in Finland reported in 2000 that human liver and intestinal enzymes are adversely affected due to exposure to glyphosate.
Effects on the Environment
The contamination of surface water is one of the effects that glyphosate has on the environment, according to the U.S. Environmental Protection Agency. This chemical can remain for 84 days in rivers, streams, ponds and lakes. Any organisms that the chemical contacts can die: they include amphibians, small mammals, earthworms, insects, fish and birds. In 2005 the University of Pittsburgh concluded that glyphosate has "extremely lethal" effects on amphibians. Soil retains glyphosate for years, according to the website Mindfully.org, enabling it to move into groundwater systems and affect nearby plants.