Herbicide---Diuron

Diuron is used as an herbicide for weed control on noncrop lands and agricultural crops such as asparagus, pineapple, cotton, and sugarcane. It is also used as a sterilant in soil, a mildewcide in paints and stains, and an algicide in fish production.

Mechanism of Toxicity  

Diuron is stable to hydrolysis (pH 5–9) and photolysis and is therefore persistent in the environment. Diuron has generally low adsorption to soils, but it is mobile, relatively persistent, and capable of transport in surface runoff to groundwater. Mobility of diuron in the soil is related to organic matter content. It has the potential to leach into ground and to contaminate ground and surface waters. Diuron, however, has low water solubility (42 ppm). It has a low vapor pressure and low probability of dispersal in air or volatilization from water or soil.

Environmental Fate

For decades, diuron has been one of the top 25 conventional agricultural pesticides used in the United States, and it is used extensively worldwide to control pre- and postemergence weeds. The annual usage of diuron in the US agriculture has recently ranged from 2 to 6 million pounds per year. It generally ranks in the top 5–7th pesticides in usage in the United States for industrial and commercial applications. Diuron is also used as biocide in antifouling paints.

Uses

Diuron is a selective inhibitor of the Hill reaction in plant photosynthesis. In some mammalian carcinogenic studies, repeated high-dose exposure to diuron appeared to work as a tumor promoter, and diuron may elicit tumor formation by inducing cytotoxicity with subsequent sustained cell proliferation.