Synoptic Risk Assessment of Groundwater Contamination from Landfills

Abstract

Waste management in Europe has improved in recent years, reducing the amount of waste disposed at landfills. However, there are still many landfills in the countries. It is well known that landfills that do not have measures in place to control leachate entering groundwater can contaminate groundwater long after the landfill is closed. Collecting monitoring results from all landfills allows permitting and management agencies to improve action plans. This relies on a synoptic risk assessment that allows prioritization and milestones to be set for required actions. The developed method of synoptic risk assessment is based on a conceptual model of the landfill and the results of chemical groundwater monitoring tested at 69 landfills in Slovenia. The study confirms that most landfills have a direct or indirect impact on groundwater quality. All landfills were classified into three priority classes on the basis of the synoptic risk assessment. The results show that a total of 24 landfills have a clearly pronounced impact on groundwater. A total of 31 landfills have a less pronounced impact due to the favorable natural attenuation capacity of the soil or the technically appropriate design of the landfill itself. A total of 14 landfills have a less pronounced or negligible impact on groundwater.

Impact assessment of the Gajke and Brstje landfills on groundwater status using stable and radioactive isotopes

“…The lowest activities were found upstream of the Brstje landfill and downstream of the Gajke landfill. Downstream of Gajke, 3 H deviates at G-4 (7.3 TU), and the southward changes show the same trend as the change in boron concentration (Cerar et al, 2019). The spatial distribution of 3 H in groundwater shows similar characteristics to TA and δ 13 C DIC (Figs.…”

“…3). The reason for the deviating values of the electrical conductivity on GAP-10/13 are the additional pressures on the groundwater caused by the Brstje landfill, which were already identified in the study by Cerar et al (2019).…”

“…The nearest surface water is the Rogoznica stream, which f lows into the Drava River southeast of the landfill (Fig. 1) (Cerar et al, 2019).…”

“…Depending on the depth of the deposited waste and the groundwater table, it is an indirect input of pollutants since the landfill is in or above the unsaturated zone. During the f lood period, the bottom of the deposit body (the outside of the liner system) is occasionally in contact with groundwater (Cerar et al, 2019).…”

“…One operational landfill in Slovenia is the Gajke landfill, where in the recharge area about 500 m upstream, there is also the closed Brstje landfill for non-hazardous waste. The results of the operational monitoring of groundwater status at the Brstje landfill showed that it has an impact on groundwater status, as warning levels for pollutants have been exceeded for several years (Cerar et al, 2019). When analysing the spatial distribution of pollutants in groundwater, it should be considered that pollutants in groundwater in the area of the Gajke landfill may originate from leachate or may be the result of contact between groundwater and waste or may already f low into the area of the landfill via groundwater from the Brstje landfill upstream.…”