6.1 INTRODUCTION

The ever-increasing amount of micropollutants emitted from agriculture, households, and industry into our environments may endanger the functioning of ecosystems. The evaluation of the ecotoxicological impact of the micro-pollutants calls for an assessment of the combined accumulation, advection, diffusion, and reaction processes that determine the exposure of the biota to the micropollutants within the ecosystem.

   My aim is to point out the possibilities and limits to predicting the exposure concentrations that might realistically exist within individual compartments of a terrestrial ecosystem. I concentrate my attention on the compartmental distribution of trace pollutants as a result of more or less long-term and back- ground pollution