The challenge of managing water and material balances in relation to eutrophication

Eutrophication is the result of overfertilisation of the aquatic environment. In other words, the detrimental effects derived from increased anthropogenic release of nutrients to the environment. By modern concepts of environmental abatement this is no longer only a question of identifying and purifying discharges. It is a question of keeping track of the system of nutrient mining, utilisation, recycle, transport, conversion, containment and release in the modern society - in effect, the total balance of nutrients in society. In Denmark, the point sources of nutrient release have been reduced by an order of magnitude. That has contributed to some improvements, but the diffuse sources have turned out to be more significant than originally expected. They are harder to reduce. That is why more integrated approaches have to be analysed. Four approaches will be analysed: the DPSIR-approach, the 5-options approach, the cause-effect relationship and the material balance analysis.