The activities of mankind which introduce excess nutrients and/or pollutants of various kinds into lakes, streams, estuaries, soils and the air, can, and often do, cause significant changes in aquatic and terrestrial environments world-wide. The pollution problem is critical because of the pressures of increasing populations, industrial growth and intensification of agricultural production. Conflicts of interest arise everywhere as challenges to resource use and natural state (‘beauty’) are turned into public issues.
