EPA-Expo-Box (A Toolbox for Exposure Assessors)
EPA currently regulates thousands of pesticide active ingredients used in agricultural, commercial, or consumer products. (See the Consumer Products Module in the Media Tool Set of EPA-Expo-Box for additional information and resources.) Pesticides can be grouped according to chemical class, the type of pest they control, the method by which they are derived, or the sites at which they are used (e.g., agricultural, residential).
- Chemical class—Chemical classes to which pesticides may belong include organophosphates, neonicotinoids, pyrethroids, and many others. Within the general class of pesticides, subcategories are sometimes defined according to a common chemical characteristic or functional group. For example, organophosphate pesticides are those that contain an ester of phosphoric acid. Subcategories that are defined by chemical characteristics may well share common qualities that would be useful when conducting an exposure assessment. Organophosphate pesticides, for example, tend to degrade relatively rapidly via hydrolysis reactions once released into the environment. See text box for more information on pesticides grouped by chemical class.
- Type of pest—Pesticides are often classified according to the type of pest they control. These groups include insecticides (to control insects and other arthropods), herbicides (to eliminate weeds), fungicides (to kill fungi), rodenticides (to control mice and other rodents), and bactericides (to disinfect or sanitize), among others. These pesticides have household, industrial, and agricultural applications; for example, insecticides may target crop-eating insects or a cockroach house infestation.
- Derivation—Pesticides can also be classified as synthetically-derived (e.g., organophosphate pesticides and organochlorine insecticides) or derived from a natural source or production method (e.g., biopesticides). Many biopesticides are derived from natural materials such as plants (e.g., citrus oil, diatomaceous earth, neem oil); bacteria (e.g., Bacillus thuringiensis toxin); or minerals (e.g., boric acid).
- Use sites—Pesticides may be registered for different types of use sites. Some are used in agricultural settings on certain types of crops. Others are used in residential settings (e.g., home and garden).
Major Groups of Pesticides Based on Chemical Class
Organophosphates and Carbamates are used as contact and systemic insecticides in agriculture and in homes. Examples include malathion, carbaryl, and chlorpyrifos.
Pyrethroids are synthetic versions similar to pyrethrins, an extract from the chrysanthemum flower.
Organochlorines and other "legacy" pesticides have historically been widely used to protect crops, livestock, buildings and households from insects. Examples include DDT, dieldrin, lindane, 2,4-D. Many of the organochlorine pesticides, including DDT, have been banned in the United States, but remain at detectable levels in the environment.