atrazine

Atrazine is a chlorinated triazine herbicide widely used for selective weed control in crops such as maize (corn), sorghum, and sugarcane. Chemically, atrazine is 2-chloro-4-ethylamino-6-isopropylamino-s-triazine, with the molecular formula C8H14ClN5. It is typically applied as a foliar spray or soil-applied formulation and is one of the most commonly used herbicides worldwide.

Mode of action: It inhibits photosystem II in plants by binding to the plastoquinone-binding site, blocking electron transport and preventing the formation of energy and reducing growth, leading to death of susceptible weeds. Because some crop varieties, notably certain maize lines, can metabolize atrazine effectively, the herbicide affords selective control when used with appropriate management.

Environmental fate: Atrazine is moderately persistent in soil and can leach to groundwater under certain conditions. It degrades via hydrolysis, photolysis, and microbial action, with degradation products such as deethylatrazine and deisopropylatrazine commonly detected in water near treated fields. Its behavior depends on soil texture, rainfall, and temperature.

Health and regulation: Human health risks are generally associated with long-term or high-level exposure, and drinking-water monitoring programs commonly assess atrazine residues. Regulators in many countries require labeling and may impose restrictions or bans in sensitive watersheds, with some jurisdictions prohibiting its use or phasing it out entirely while others maintain registered uses with conditions.

Atrazine remains widely used but subject to ongoing regulatory review and environmental monitoring to address water quality and ecological concerns.