These tasks are mostly carried out in relation to the removal of various environmental disasters or old environmental liabilities. These usually are simulations of the transport of solutes of some organic (fuels, solvents, oils or residues from various industrial production) or inorganic contaminants (usually heavy metals), which interact with the aquifer environment thereby affecting the chemical composition of waters as well as causing changes in the composition of the contaminants themselves. The contaminants may sorb to clay particles or organic material, or they can also be subject to chemical and/or natural degradation intensified by bacteria that are present in the aquifer. All these processes, along with advection and hydrodynamic dispersion, are well known and documented, and as such can be simulated by means of mathematical models.
