MATHEMATICAL-MODELS FOR ESTIMATING FLUXES AT THE SEDIMENT-WATER INTERFACE IN BENTHIC CHAMBER EXPERIMENTS

Experimental data collected by means of benthic chambers have been use d to develop simple mathematical models in order to predict heavy meta l and non-metal fluxes at the sediment-water interface. In particular, two mathematical models have been applied to Ba, Co, Fe, Pb, Mn and C u. Both models estimate benthic fluxes by means of Fick's law but they differ in the modelling of partition between liquid and solid phases. The first model, which is appropriate for Ba and Co, assumes that sor ption is the most important process in determining partition. The seco nd model, which gives discrete results for Fe and Pb, assumes that pre cipitation is the most important process determining the time variatio n of concentrations. Neither model is suitable to explain experimental data for Mn and Cu. This paper demonstrates the benefit of the use of mathematical models in the interpretation of benthic chambers experim ents and in the identification of the relevant processes occurring at the sediment-water interface.