A strategy for the assessment of continuous and pulsed contaminants in river and estuary ecosystems in the Arctic

A transfer of contaminants from the land through the rivers forms a significant part of the Arctic seas' pollution. A whole ecosystem is the target of this harmful action. The response of the ecosystem can be considered as the measure of the impact. To assess this impact we designed a mathematical approach based on the Liebig-Shelford law of tolerance, the "narrow path" principle and the Shannon index of diversity to evaluate a prosperity function and a comprehensive risk index for a river or estuary ecosystem. To illustrate this general approach we consider the propagation of the pollutant along the river bed after (1) continuous and (2) pulsed release of a pollutant. The results of calculations show good correspondence with the actual behaviour of natural ecosystems. Further studies are necessary to find out the actual values of the parameters for different pollutants.