The chemical status of groundwater in unconfined and highly permeable aquifers depends on natural and anthropogenic influences. Anthropogenic sources of increased mineralization are often landfills, where dissolved ions and minerals are distributed throughout the aquifer depending on the direction of groundwater flow.
The Črneče municipal landfill is located in the north of Slovenia, near the village of Črneče. The analysed area is a highly permeable alluvial plain consisting of Quaternary sediments deposited over bedrock of poorly permeable metamorphic rocks. There are two surface water flows in this area. The irregular groundwater flow and high permeability of the area allow the migration of contaminants throughout the area. The chemical composition of groundwater in Črneče is determined at four observation boreholes. The concentration of inorganic species can determine the natural background of the studied area, but their elevated values can also reflect the pollution of groundwater. In our study we investigated the presence of trends of temporal dependence of parameter concentrations, trends of parameter concentrations as a function of groundwater level and the presence of trends of co-dependence of concentrations of different parameters. Data processing confirmed the presence of these trends, but they vary depending on the hydrogeological site. Subsequent hydrogeochemical analysis confirmed the equilibrium of groundwater with minerals calcite and dolomite, mineralization increases in the downstream direction. The results of statistical and hydrogeochemical analysis showed that the dynamics of groundwater is reflected in its chemical status. Increased concentration of inorganic ions and increased mineralization at the downstream boreholes indicate the influence of the landfill, moreover, the scatter of the values of the observation borehole POČ-1 reflects the additional influence of Drava River. The chemical status of groundwater at upstream borehole POČ-2 indicates the amount and chemical status of precipitation and inflow of groundwater from the southern hinterland. Stable conditions are evident in observation borehole POČ-3, which is not influenced by external factors. Groundwater at this site reflects the natural condition of groundwater in the observation area.
Area coordinates (D48/GK): GKX: 161235,56 GKY: 499585,85; GKX: 161095,15 GKY: 499556,80; GKX: 161100,98 GKY: 499732,60; GKX: 161194,4, GKY: 499708,87.
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