Abstract Determinations of constituents present in soils and soil solutions at trace concentrations are conducted primarily because of interest in soil as a medium for plant growth or because of its influence upon the solute chemistry of fresh waters and ground waters. Interest may arise from concern over potential toxicity effects or over adverse effects of deficiency of trace nutrient elements essential to soil or freshwater biota. In the above context, total amounts of elements present in soil are generally of less interest than water-soluble or labile, plant available forms (Marr & Cresser 1983). Rhizosphere soil may be more relevant than bulk soil in assessing plant availability. Over recent decades, optimal chemical extractants (such as EDTA or DTPA for Zn and Cu) have been selected which reflect plant availability of trace elements in terms of high correlations between plant tissue and soil extract concentrations. Occasionally full speciation is conducted. M. S. Cresser & E. El-Sayad (unpublished results), for example, have measured water-soluble, exchangeable and organically bound trace elements, and those in carbonate and amorphorus and crystalline iron and manganese oxides, and residual sand, silt and clay minerals. Such detailed analysis is valuable in elucidation of soil pedogenesis (El-Sayad et al. 1988).