Atrazine is an herbicide that is widely used to selectively control annual grasses and broadleaf weeds before they emerge in several agricultural crops, with the highest use on field corn, sweet corn, sorghum, and sugarcane. It is also used on wheat, macadamia nuts, and guava, as well as non-agricultural uses such as nursery/ornamental and turf. Atrazine is part of the triazine family of herbicides, and it is chemically related to two other herbicides, simazine and propazine. It is also used to control weeds in residential lawns and on golf courses.

Atrazine is a surface water and groundwater contaminant that can enter waterways in agricultural runoff from row crops. It can reduce primary production in aquatic communities by inhibiting photosynthesis, has been linked to adverse reproductive effects in amphibians and other wildlife, and is currently being studied as a potential endocrine disruptor and carcinogen to both aquatic and human life.

Atrazine is slightly to moderately toxic to fish, including guppies and rainbow trout, following exposures of four days or less. It is highly toxic to freshwater invertebrates and very highly toxic to marine invertebrates, including midges and marine shrimp. It is slightly toxic to water fleas. Atrazine is practically non-toxic to honeybees through short-term contact or ingestion. It is very low in toxicity to earthworms.

In summary, atrazine is an herbicide used to selectively control annual grasses and broadleaf weeds before they emerge in several agricultural crops, as well as non-agricultural uses such as nursery/ornamental and turf. It is also used to control weeds in residential lawns and on golf courses. However, it is a surface water and groundwater contaminant that can enter waterways in agricultural runoff from row crops and has been linked to adverse reproductive effects in amphibians and other wildlife.