The state-of-the-art of available methods for predicting the effects of high chemical concentrations on the properties, processes, functions, cycles, and responses of terrestrial and aquatic ecosystems was reviewed. Environmental problems associated with high chemical concentrations can occur in soil and water at landfills; landfarms; spill sites; and sites where chemicals were produced, used, stored, or discarded. Considerable information is available on effects of trace chemical contaminants, such as pesticides, polychlorinated biphenyls, chlorinated hydrocarbons, and metal ions, in the respective ecosystems. Predictive techniques are becoming available to describe transport and transformation of such contaminants and, thus, their fate and distribution in certain components of the environment. Present predictive methods and models that trace transport and transformation of chemical species are based on 'natural' soil and water properties such as density, porosity, infiltration, permeability, viscosity, hydrophobicity, and diffusivity.