A MODELING PROCEDURE TO EVALUATE THE COHERENCE OF INDEPENDENTLY DERIVED ENVIRONMENTAL-QUALITY OBJECTIVES FOR AIR, WATER AND SOIL

Sets of independently derived environmental quality objectives (EQOs) for air, water, and soil may not be coherent in that maintaining the c oncentration at EQO level in one compartment may lead to exceeding EQO levels in other compartments. A methodology to evaluate this coherenc e is suggested. Starting from a steady concentration in the compartmen t of focus (the primary compartment), steady-state concentrations in t he adjacent (secondary) compartments are estimated using a multimedia fate model. If air is the primary compartment, steady-state concentrat ions in water and soil close to the equilibrium concentrations can be expected, and coherence of EQOs can be evaluated easily by means of an extended equilibrium partitioning procedure. If water or soil is the primary compartment, the steady-stale concentration in air is usually well below the equilibrium concentration. Subequilibrium steady-state concentrations are sensitive to assumed model parameters. The procedur e is illustrated with the results of a coherence analysis for seven ch emicals for The Netherlands.