The rhizosphere contains important factors controlling nutrient dynamics in this zone and the mineral nutrition of plants. Nutrient dynamics also influence the environment of the rhizosphere. The nutrients and heavy metals in the rhizosphere change when soil is amended with sewage sludge. However, little attention has been given to the extent to which plant roots affect the availability and distribution of heavy metals near roots in soils amended with sludge. The objectives of the present study were to investigate the distribution of heavy metals and nutrients in the rhizosphere of Brassica campestris grown in sludge-amended soil, and to predict the availability of metals in sludge-amended soil. The distribution of nutrients and heavy metals in the rhizosphere in sludge-amended soil was investigated using the root mat and a frozen thin slicing technique to provide indications regarding the activation of heavy metals. DTPA-extractable Zn, Cd, Ni, and Mn, available P and K, and ammonium nitrogen in the rhizosphere were markedly depleted when soil was amended with sludge. There was no conspicuous depletion or accumulation of DTPA-extractable Cu in the rhizosphere when the soil was amended with sludge. The pH value in the rhizosphere increased with distance from the roots when soil was amended with larger amounts of sludge. The exchangeable fraction of Cu in the rhizosphere was depleted whether or not the soil was treated with sludge. Carbonate, oxide, organic, and residual fractions of Cu and Zn were depleted in the rhizosphere at a distance of 0-2 mm from the roots when soil was amended with 50% sludge. Application of sewage sludge had a positive effect on Brassica campestris growth. With an increase in sludge amounts, the concentrations of Cu and Zn in aboveground parts of Brassica campestris did not change. Soil amendments with less than 25% sludge did not increase the availability or mobility of heavy metals. The depletion in rhizospheric DTPA-extractable Zn, Cd, and Ni indicated that with the sole exception of Cu, release of metals from sludge-amended soil was very limited.