Landfill leachate quantity and attenuation distance of inorganic contaminants in the groundwater of different hydrogeological systems: a case study of Lithuania

Abstract

This study examines the relationship between the quantity of landfill leachate and attenuation distance of inorganic contaminants in the groundwater of open, semi-open and closed hydrogeological systems. Nearly 2,000 groundwater samples were collected and 12 inorganic chemical parameters were investigated, of which NH4+, K+ and Fe were considered to be the most groundwater polluting chemical parameters. Analytical modelling of pollution migration, multivariate statistical techniques and a single factor pollution index method were applied for data processing. The results showed that irrespective of waste volume, the degradation coefficients of NH4+, K+ and Fe were by 36–90% higher in the groundwater of open hydrogeological systems, where attenuation distances were by 14–56% shorter compared with those in closed hydrogeological systems. Also, the degradation coefficients of NH4+, K+ and Fe+ in the groundwater of very small and small landfills were by 37–90% higher and attenuation distances were by 38–99% shorter compared with those in the groundwater of large and very large landfills. In the groundwater of very small and small landfills the difference between NH4+, Fe and K+ attenuation distance in open and closed hydrogeological systems was about 89–97% lower than the difference in large and very large landfills. This finding indicates that the quantity of leachate is the main factor of attenuation of contaminants in groundwater. The results obtained in this research may be used to predict the dispersion of pollution in the groundwater of landfills located in similar hydrogeological systems and to take environmental protection measures.