A robust testing system for imidazolinone residues is to be developed using Diffusive Gradient in Thin-Films (DGT) technology. This tool will provide information on bioavailability of herbicide residues independent of soil type characteristics. The DGT tool will be validated in spiked soils, in a range of soil types and two water regimes. The DGT tool for glyphosate residue is also to be assessed.