Groundwater contamination plume monitoring in sealed waste dumps

Sealing waste dumps does not mean that they are no longer an environmental hazard, since almost all of them were constructed many years ago, without taking into account environmental regulations. Therefore, after being closed, a monitoring plan should be implemented and, when necessary, characterization studies must be undertaken to avoid unforeseen problems.To design monitoring plans for these areas, it is essential to have knowledge of local geology and hydrogeology, since potential contamination of soils and groundwater depends essentially on the physical characteristics of the area (e.g. porosity and permeability) and local dynamic of fluids (e.g. groundwater level, flow direction).This paper presents a methodology for monitoring the surrounding area of sealed waste dumps and for determining the presence of contamination in groundwater, based on Portuguese experience.