Geochemical Anomalies in Soils and Surface Waters in an Area Adjacent to a Long-Used Controlled Municipal Landfill

Abstract

Municipal landfills, even when controlled, are potential sources of soil and water pollution in surrounding areas, due to the migration of pollutants through water and air. This research assesses geochemical anomalies of heavy elements and rare earth elements in soils and surface waters in an adjacent area to a controlled municipal landfill near Madrid (Central Spain), under long-term operation. Twenty soil and eighteen water samples were collected in 2017 and 2018 and analyzed for this purpose. Spatial distribution and concentrations of heavy elements (Ag, Cd, Cu, Mn, Ni, Pb, Tl, and Zn) and rare Earth elements (La, Ce, and Gd) are heterogeneous and significantly higher than soil background levels, but below the legal limits to consider intervention. Accumulation of heavy and rare Earth elements in soil nearest the landfill is attributed to occur via wind and wind-driven rain transport, while their accumulation in sediments is attributed to water transport through the creeks. Surface waters show large contamination by organic and inorganic compounds and influence geochemical anomalies in sediments. The water quality is below allowable concentrations for drinking water. The combined evaluation of the soil and water samples performed in the present work is proposed as a pilot study that may be applicable to similar surrounding landfill areas worldwide.