Modeling of Contaminants in Aquatic Environment

Abstract

Integrated water management in river basins is accepted as a guiding principle in many countries, including Bulgaria. The challenges faced in watershed modeling have been reflected in the need to consider explicitly linkages among hydrology, geochemistry, environmental biology, meteorology, and climatologic variability. The shortage and pollution of fresh water require application of modern tools for solving the problems. For this reason, the application of technical aids in watershed planning and management is widespread in the world practice at present. Furthermore, due to the same reason public interest in the field of risk analysis, assessment and management has expanded recently. Risk analysis has emerged as an effective comprehensive procedure that supplements and complements the overall management of all aspects of our lives. Management of health care, environment and physical infrastructure systems, e.g. water resources, etc., acquires still greater importance. The use of mathematical models in this domain increases continuously. The application of water quality models is considered and the concept of water body integrity is described. This concept represents the main basis of many methods and mathematical models developed for determining the “real” water systems, so that a balance between the “functioning of water system” and “the impact of the water chain” is achieved. Fate models with or without a risk assessment component and ecotoxicological models are characterized in brief, and the points that should be clarified before entering the modeling procedure are outlined. It is pointed out that the complete solution of ecotoxicological problems requires in principal the consideration of four sub models. The results of modeling nutrient emissions in river systems are given, where main sources and pathways are taken into account to calculate the nutrient input into river systems by the MONERIS model, for example. They could be used for risk assessment of nitrogen and phosphorus export on watershed level.