EFFECT OF MUNICIPAL LANDFILL LEACHATE ON THE CONTENT OF NITROGEN FORMS IN UNDERGROUND AND SURFACE WATERS

The study has been carried out on the grounds of a municipal landfill in Brodnica. Water samples were collected from 6 sites in different locations. It has been demonstrated that the values of total nitrogen concentrations as well as mineral forms of this element in leachates, ground and surface water were highly varied. In the landfill leachate, the total nitrogen content reached 216.7 mg N dm(-3), of which 91.6 % consisted of ammonia nitrogen, 2.9 % was nitrate(V) nitrogen and 0.08 % was nitrate(III) nitrogen. The quality of deep groundwater sampled from an observation borehole drilled on a site where groundwater flows towards the landfill basin corresponded to water purity class I, but fell to class V for groundwater collected from a piezometer situated behind the landfill basin, where the water flows away from it. The total nitrogen and mineral nitrogen forms in groundwater depended on a sampling site. Further away from the landfill cap, concentrations of total and ammonia nitrogen were lower. Considering the above parameters, the quality of groundwater sampled from a piezometer closer to the landfill was within class V, but water samples taken from a piezometer situated further away from the landfill were assigned class II or III. No negative influence of the landfill on the quality of surface waters has been observed as over 94 % of the determinations of biogenic substances did not exceed the threshold values established for water purity class I.