The influence of landfills located in different hydrogeological systems on Lithuanian groundwater quality

The article presents data on influence of non-operational landfills located in different hydrogeological systems on Lithuania groundwater quality. The landfills are located in open, semi-open, semi-closed and closed hydrogeological systems. The prevailing values of total dissolved solids (TDS) in the most intensive groundwater pollution zones of landfills can be divided into four TDS levels: low (400-3000 mg/l), moderate (TDS 3000-5000 mg/l), high (TDS 5000-20000 mg/l) and very high (TDS 20000-32000 mg/l). Groundwater with a low TDS level prevails in the most intensive groundwater pollution zones of landfills in open and semi open hydrogeological systems. Groundwater with high and very high TDS levels characterizes about 3% of landfills in open and semi-open hydrogeological systems. The landfills in semi-closed and closed hydrogeological systems are also characterised by groundwater with a low TDS level. No landfills with a very high TDS level were found in semi-closed and closed hydrogeological systems.