Extractive Spectrophotometric Assessment Of Diuron Herbicide Leaching Risk In Five Soils

摘要

This paper investigates the adsorption and leachability of diuron herbicide as these processes control its migration from soil to water bodies and consequently influence the surface and groundwater contamination. Adsorption of diuron, using the batch equilibrium technique, has been studied on five soils of different characteristics for which a spectrophotometric methodology has been developed based on the reaction of dimethyl amine (formed from hydrolysis of diuron with potassium tert.-butoxide) with carbon disulphide and nickel (Ⅱ) acetate to form methyl isobutyl ketone (MIBK) extractable yellow nickel (Ⅱ) dimethyl dithiocarbamate [Ni(DTC)_2] complex showing λ_(max) at 428 nm. The method has also been applied to the determination of diuron in a commercial formulation and in residues on agricultural produce and water for the purpose of getting reliable adsorption data and predicting health hazards. The leaching risk of diuron in terms of groundwater ubiquity score (GUS) index was evaluated and shows values in the range 1.97-2.12, which classifies it as a transition leacher and has a potential to contaminate ground and surface water resources. The present study reveals the serious contamination status of surface and groundwater by this herbicide.