As well as high-ionic-strength flocculation, which is a risk in many applications, soil poses a unique challenge as nanoparticles could stick to soil mineral surfaces, which in particular include aluminosilicate and metal oxide surfaces that can present both positive and negative charges. Furthermore, the potential interaction with of soil organic matter is unknown. To investigate the stability of the micelle-templated gold nanoparticles against these effects, a nanoparticle solution was mixed with an air-dried sandy-loam textured agricultural soil (Eutric Cambisol), to create a slurry which was then shaken for 24 h. The soil solids were then removed by centrifugation. Analysis of the supernatant, i.e. the micelle-templated gold nanoparticle solution showed no significant reduction in the gold concentration compared with the original solution (Fig ). This indicates that essentially all the nanoparticles remain in solution, and essentially none have adsorbed to or been taken up by the solid mineral or organic phases, exactly as is required for application in imaging the soil aqueous phase. Labelling of the soil aqueous phase with high stability and contrast in X-CT