Konieczność walidacji monitoringu wód podziemnych w rejonach starych składowisk na przykładzie składowiska fosfogipsów w Wiślince (Żuławy Gdańskie)

Abstract

The necessity of validation of groundwater monitoring in the regions of old dumping sites – a case study of a phosphogypsum dump at Wiślinka (Vistula Delta Plain).A b s t r a c t. The phosphogypsum waste dump near Gdańsk was located within the Vistula delta depression on alluvial and lacustrine deposits close to the Dead Vistula River in the early 1970s. More than 16 million tonnes of waste deposits was accumulated until 2009. The loam outcrop of the old brick-yard was used for phosphogypsum. The leachates from the waste deposits causes the migration of contaminants due to density and hydraulic gradients down to the Vistula delta aquifers. The leachate is characterised by low pH, very high concentrations of phosphates and sulphates, metal ions, and radioactive elements. The waste dump was ultimately closed in 2009. The dump’s surface has been covered with municipal sewage sludge, as the so-called biological reclamation reduces the dustiness of phosphogypsym and the quantity of leachate, but generated additional threat resulting from the chemical compounds of the sludge. The matter from the municipal sewage sludge, dumped on the surface of the phosphogypsum waste heap, contained hormone disruptive compounds (EDCs), nitrogen compounds, viruses, bacteria and other pathogens. The existing groundwater monitoring started in the mid-1970s and was projected and constructed in a very simple way. The observation wells and piezometers have been screened over a short distance at the bottom. Contaminants of different densities, liberated to the aquifers underneath, cannot be properly detected. The new analytical procedures are implemented in chemical laboratories and new methods of monitoring, e.g. low flow sampling, are now in practice. Also the climate changes and sea level rise along the Baltic coast require a new approach and validation of groundwater monitoring in the surroundings of the old waste dumps of chemical and mining industry.