Objectives: To obtain better insight into the factors regulating the fate, distribution and impact of organic and inorganic pollutants in the coastal zones of Costa Rica. To develop useful normalization procedures for organic and inorganic pollution monitoring in tropical regions. For organic pollutants, the presence of specific lipid classes in biota and sediments will be considered. For inorganic pollutants, the importance of metal speciation and metal binding sites will be emphasized. The influence of environmental factors (temperature, pH, the presence of particulate and dissolved organic matter (POM and DOM) on the distribution and bioavailability of organic and inorganic pollutants will be discussed. To develop accumulation models for organic and inorganic pollutants, useful in pollution impact assessment studies. Possibilities for extrapolation of pollution monitoring data among biological compartments, among ecologically different ecosystems and towards other organic compounds will be evaluated. 4) To obtain basic information on the state of the Costa Rican marine environment through pollution improved management policies.