Fig. 4. Three dimensional reconstructs of the sulforhodamine B 20 mg L^-1 total concentration isosurfaces and that of the large pores or less dense regions in two soil cores from the 0.5- to 0.6-m layer and one from the 0.2- to 0.3-m layer. The concentration isosurfaces were derived from concentration maps on horizontal core cross sections and the large pores or less dense regions from binarized x-ray computer tomography (CT) images.