Ivars Neretnieks

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A conceptual model, which is a unitary and continuous description of the overall processes in waste deposits, has been developed. In the model the most important processes governing the long-term fate of organic matter in landfills and the transport and retention of toxic metals are included. With the model as a base, a number of scenarios with different(More)
The long-term chemical evolution in waste deposits and the release of toxic metals was investigated. The degradation of organic matter and hence the potential efflux of heavy metals in a long-term perspective was studied by defining some scenarios for waste deposits containing organic compounds, different longevity and functions of covers and different(More)
The Oostriku peat bog (central Estonia) has been exposed to metal-rich groundwater discharge over a long period of time and has accumulated high concentrations of Fe (up to 40 wt-%), heavy metals (e.g. Pb, Zn, Mn, Cu), and As. In this study, the peat was characterised with respect to composition and metal content with depth. The peat pore water was analysed(More)
Some of the basic assumptions of the advection-dispersion model (AD-model) are revisited. This model assumes a continuous mixing along the flowpath similar to Fickian diffusion. This implies that there is a constant dispersion length irrespective of observation distance. This is contrary to most field observations. The properties of an alternative model(More)
Some recent converging tracer tests with sorbing tracers at the Aspö Hard Rock Laboratory in Sweden, the TRUE tests, have been predicted using only laboratory data and hydraulic data from borehole measurements. No model parameters were adjusted to obtain a better fit with the experiments. The independent data were fracture frequency and transmissivity data(More)
In this paper, a new in situ method for obtaining the formation factor, which is essential for the matrix diffusion, is described and tested in intrusive igneous rock. The method is based on electrical resistivity measurements in rock where the pore water and rock resistivities are essential parameters. The method is based on electromigration instead of(More)
Two new methods for determining sorption coefficients in large rock samples have been developed. The methods use electromigration as a means to speed up the transport process, allowing for fast equilibration between rock sample and tracer solution. An electrical potential gradient acts as a driving force for transport in addition to the concentration(More)
Within the framework of density functional theory, a weighted correlation approach is developed in order to obtain the density distributions of an inhomogeneous fluid. It results in a formally exact expression, by means of the concept of a weighted pair correlation function, used to evaluate the change of the single-particle direct correlation function of(More)
A model is developed to describe solute transport and retention in fractured rocks. It accounts for advection along the fracture, molecular diffusion from the fracture to the rock matrix composed of several geological layers, adsorption on the fracture surface, adsorption in the rock matrix layers and radioactive decay-chains. The analytical solution,(More)