Abstract
Through the introduction of the research on the dynamics of chemicals on a regional scale and research on the partition of chemicals between sediments and their overlying waters, a method for predicting the fate of persistent organic pollutants is discussed. First, we show observations on the diffusion and deposition near roads, the photolysis on the ground and the runoff during rainfall, the dynamics in Hiroshima Bay and its watershed, and the uptake by fish, with special reference to Polycyclic Aromatic Hydrocarbons (PAHs) . It is suggested that the diffusion in the air over the regional environment, the runoff of the deposited ones, and sedimentation in the bay are the key processes in the case of PAHs. Second, we show a method for predicting the partition coefficients of persistent chemicals between sediments and water and/or between particulate and dissolved components, using both the analysis on the relationship between sediments and overlying waters based on the report “Chemicals and Environments”, and the measurement of PAHs and Organicphosphoric acid triesters (OPEs) in the natural environment and the experiments regarding sorption and desorption. It is indicated that the sorption to inorganic components and/or the extent apart from the chemical equilibrium are crucial to estimate the partition coefficients.
