Landfilling is the most popular method of waste treatment in Poland. Old and usually uninsulated landfills constitute a major source of contaminants, which are leached by precipitation waters. As rainwater percolates through a landfill, suspended and dissolved components, waste decomposition products and various microorganisms are leached. Given the lack of any protection against leachate contacting groundwater, contaminants spread over a distance ranging from dozens of meters to several kilometers. The purpose of this paper was to determine the degree of contamination of leachate and groundwater with heavy metals (manganese, iron, nickel, chromium, zinc, copper, lead and cadmium) in the surroundings of the Maoelice municipal landfill site in Wroc³aw. The landfill was created without prior insulation of its base, and it has accumulated ca 2.4 mln m3 of waste in over thirty years of its use. Studies on the groundwater were carried out from 1995 to 2008, and the examination of the leachate was concluded in 2004. The analysis of the results shows that the groundwater flowing to the research object is already contaminated. While water percolates through the uninsulated base of the landfill, its quality continues to deteriorate. A large quantity of accumulated waste contributes to the severe contamination of the groundwater. Leachate from the insulated part of the landfill displayed properties that correspond to “old” landfills. Inside such landfills, the processes occurring during the methanogenic phase of waste decomposition are abundant. Concentrations of heavy metals found during the research (except some characteristic values of iron and chromium) were within the limits that allow discharge to sewage facilities, surface waters or soil. Changes in the content of analyzed heavy metals in the leachate and groundwater give a reason to suppose that in the years to come the amount of leached contamination may grow. Thus, it is necessary to continue the research – even in a scope broader than required by regulations concerning the monitoring of landfills.

17.4.2012