Introduction

Abstract

The determination of the total content of contaminants in soils is clearly important. However, quantification of the bioavailable fraction of the contaminants is equally, if not more important as it is this fraction which determines the effective risk from the contaminated material. The readily soluble fraction of a contaminant is generally considered to be bioavailable but there is growing realization that current methods of assessment of readily soluble and bioavailable need re-evaluation and that bioavailability of a contaminant may vary both in time and space. There is also growing interest in the movements and transfers of contaminants between compartments/pools in the soil-plant ecosystem and to linked systems. Modelling of transfers from sources to targets (e.g. plants, microorganisms, mesofauna, fish) requires knowledge of the relevant mechanisms and factors which govern the speciation and bioavailability of contaminants and their transfers.