Experiments were undertaken to investigate the influence of different soil amendments and plant species on rhizosphere pH, water-soluble metals (Cd, Cr, Cu, Ni, Pb, Zn) and ammonium nitrate-extractable metals in rhizosphere soil. Plants were grown in specially constructed root study containers designed to enable sampling of soil at 0.5 mm increments from the root mat. The rhizosphere soil was sectioned using a rotary microtome. The soil used in these experiments had received several applications of biosolids over a period of 30 years, and contained substantial concentrations of heavy metals. The plants grown were sunflower, wheat, spinach, mustard and rape. Soil amendments included different rates of ammonium sulphate, ammonium nitrate and citric acid. The thin-slicing technique proved to be generally successful for sampling incremental rhizosphere soil samples, however, soil from several replicate root study containers had to be bulked to obtain sufficient soil for analysis. The results showed that in all cases, rhizosphere pH decreased towards the plant root, although the extent of the pH change varied between plant species and soil treatment. pH values in the 0.5 mm increment closest to the plant root were generally 1 unit lower than in the bulk soil at a distance of between 3.0 to 4.0 mm from the root. In contrast, most water-soluble and ammonium nitrate-extractable metal concentrations decreased with distance from the root surface. However, there was one marked exception for copper, in the presence of citric acid, where a depletion zone close to the root was observed.