Laboratory leaching tests are indispensable for waste acceptance, compliance screening and materialcharacterisation, but they are poor predictors of landfill behaviour when used as stand-alone field-emissionindicators. Their results are protocol-conditioned measurements of potential release, obtained under controlledliquid-to-solid ratio, pH, contact time, flow configuration and specimen geometry. They therefore describelaboratory release functions, not the time-dependent concentration or flux that will occur in an evolving landfillbody. This distinction is critical because Council Decision 2003/33/EC establishes waste acceptance criteriapursuant to Directive 1999/31/EC, including leaching limit values for granular wastes and equivalent protectionrequirements for monolithic wastes, but these legal thresholds define admissibility under standardised conditionsrather than long-term landfill emissions 1819.This paper reviews the principal leaching methods used in waste and landfill assessment, including TCLP Method1311, EN 12457 batch tests, EN 14429 pH-dependence tests, EN 14405 percolation tests, EN 15863 monolithicleaching tests and the LEAF 1313–1316 methods 5–17. It distinguishes compliance screening, materialcharacterisation, process-based source-term derivation and field prediction. The central argument is that elutioncurves become scientifically and engineeringly meaningful only when transformed into model-based source termsthrough hydrological scaling and reactive-transport interpretation 1–5. A numerical literature-based case studyillustrates this point: for a 3 m waste layer compacted to 1500 kg-dry·m⁻³ under 0.25 m·y⁻¹ net infiltration,laboratory L/S values of 0.2, 0.5, 2, 5 and 10 L·kg⁻¹ correspond to approximately 3.6, 9, 36, 90 and 180 years offield percolation, respectively 5. Consequently, direct comparison between eluate concentrations and fieldleachate concentrations is physically misleading unless L/S is mapped to time, water flux and deposit geometry.The paper further shows that landfills behave as evolving reactive porous media in which porosity, permeability,tortuosity, pH/Eh conditions, dissolved organic carbon, biofilm development, mineral precipitation–dissolution andreactive sink capacity change over time 2320–2429–34. These processes modify contaminant accessibility,retention and remobilisation, so that field release depends on coupled flow, reaction and structural evolutionrather than on the laboratory curve alone. The review concludes that leaching tests remain necessary boundarycondition tools, but reliable landfill assessment requires process-based translation into source terms andsubsequent coupling with water-balance, geochemical and reactive-transport models.
Sebastiano et al. (Wed,) studied this question.