Are Herbicides Toxic?

An herbicide is an agent used to prevent vegetation from growing. Although there are many at home remedies that can be used for this purpose, herbicides are primarily synthetic chemicals manufactured for use in the agriculture, industrial, and ornamental and turf industries.

The stigma of herbicides is that since they are toxic to plants, they must be toxic to humans. In the past, most herbicides were dangerous to handle and potentially toxic, but most of these products have since been replaced with a toxic-free product. Pesticides now must go through rigorous testing by the U.S. Environmental Protection Agency (EPA) before they can be sold. Many household cleaning products now hold a much higher toxicity level than herbicides being used on plants!

Herbicides target highly specific biological processes within plants (think: photosynthesis). However, mammals, including humans, do not photosynthesize, making herbicides that target photosynthesis have very little impact. Therefore, since these herbicides are not able to be used in our bodies, they are often excreted in urine within 24 hours of the dose. This flushing of the herbicide does not allow concentrations to build up to toxic levels within the body. Our bodies are well equipped to safely dispose of accidental exposure to many common herbicides.

In this table, put together by the faculty at the University of Florida, LD50 levels are compared between commonly used products and herbices. LD50 values is a measurement used to document toxicity. LD50 is the amount of chemical required to provide a “lethal dose” to 50% of the test population. LD50 is measured in mg of chemical administered per kg of body weight. The lower the LD50 value, the less chemical that is required to reach lethality.