The bulk diffusion co-efficient in the soil environment can be compared with the single particle diffusion co-efficient for the gold nanoparticles in water. we have done earlier, the diffusion coefficient is found by measuring thermal fluctuations that can alternatively be processed to output a diffusion constant. The measured diffusion constant, Dsingle of the micelle-templated gold nanoparticles in dilute solution (3.24 mg(Au)/ml) is 1.50  10 -11 m 2 s -1 (Table ). Intriguingly this is nearly an order of magnitude smaller than the bulk diffusion constant measured in soil. This contradicts intuitive expectations, since one would expect the more respected space of the soil environment to lower rather than raise the speed of diffusion.