Measured and Estimated Volatilisation of Naphthalene from a Sandy Soil

The non-steady-state fluxes of naphthalene from an artificially contaminated sandy soil at different water contents were measured in the laboratory, at 10°C. The soil contained 1.1% of organic carbon and the water content varied between 2.8 and 14% w/w. The diffusive flux of naphthalene from the soil was modelled by the numerical code RIOCATS assuming instantaneous equilibrium of naphthalene between soil air, soil water and soil solids. The latter equilibrium was described by a linear or a Freundlich isotherm experimentally determined for the actual soil. The model generally overestimated the fluxes by a factor of 1.5 to 6.4. The largest deviation between predicted and observed dynamic fluxes was found at high water contents. For the cover soil, half-life times of 1 to 2 days were estimated by the model for naphthalene degradation.