GROUNDWATER AND SURFACE WATER QUALITY ASSESSMENT NEAR THE CLOSED MUNICIPAL LANDFILL

Abstract

During the current research the level of groundwater (piezometers P2,P3,P4) and surface water (reservoir B) contamination during landfill operation and after its closure were examined. 113 samples of groundwater and surface water were collected from spring 2005 until spring 2012, i.e. three years after the landfill closure. The samples were analyzed for pH, EC, PAH, TOC and six heavy metals: Cr, Hg, Zn, Pb, Cd, Cu. The heavy metal concentration in groundwater and surface water both during landfill operations and after the landfill closure remained on a similar level and did not exceed permissible levels determined by WHO. Cr was an exception, because its concentration, during landfill exploitation, reached the value of 0.028 mg/l in surface water. In all examined after the landfill was closed a decrease in the EC value was observed. With the landfill closure the TOC concentration in groundwater increased from 1.8–3.4 to 2.07–3.6 mg/l and the PAH concentration from 0.01 to 0.02 mikrog/l. It may be attributed to a slowdown of decomposition in landfill. An additional PAH source for ground and surface water are surface run-offs form road pavements, yards and parking lots. The remaining high TOC level in a surface reservoir after the landfill closure is also a result of eurotrophisation, which enriches water with organic substances. Seasonal changes in the concentration of pollutants were observed, resulting both from their dilution by atmospheric precipitation (EC, pH, Cd, Cu) and due to washing them out from neighboring areas and enriching with them the analyzed water (Cu, PAH, Hg).