Assessment of soil diuron bioavailability to plants and microorganisms through non-exhaustive chemical extractions of the herbicide

Aging of diuron contaminated soil during 100 days drastically decreased the percentage of diuron recovered by the selected extractants in all the tested soils. Results showed statistical correlations between non-exhaustive chemical diuron extraction and biological measurements when the extractant was n-butanol, showing to be the most reliable chemical technique capable of predicting both, diuron bioavailability for microorganisms and for plants. HPBCD was also capable of detecting diuron bioavailability only for microorganism, although with worse statistical data, while the third extractant, CaCl2 aqueous solution, showed to be the least reliable for both assays. The results presented demonstrated that a non-exhaustive chemical extraction using n-butanol as extractant may serve as the basis for a simple and rapid procedure to assess diuron bioavailability in contaminated soils with different characteristics.