Beyond the material grave: Life Cycle Impact Assessment of leaching from secondary materials in road and earth constructions

Life cycle assessment of construction and demolition waste management

“…Similarly for human toxicity, pathways for soils might involve processes such as ingestion or dermal contact, which might be relevant for topsoils, but not for subsoil. As a consequence, the fraction of pollutants remaining in the subsoil (Table 2) could not be assigned CFs for emissions to ''soil''; thus, we chose to use CFs for emissions to ''freshwater'' for the fraction immobilised in the soil (that is, the numbers shown in Table 2), following the approach of Schwab et al (2014). Therefore, the fractions reported in Table 2 represent the amount of pollutants immobilised by the soil (due to sorption processes) within 100 years, but which could potentially be released to shallow groundwater (eventually ending up in a freshwater body and affecting human health and ecosystem) in the future; hence, they should be regarded as ''stored'' freshwater and human toxicity.…”

“…The leaching emissions may be accounted for in different ways: the leachate may be assumed to be released directly into a soil compartment (Chowdhury et al, 2010) or directly into a water compartment (Olsson et al, 2006;Toller et al, 2009). Due to the way in which leaching has been modelled thus far in LCA, the potential immobilisation processes in the subsoil immediately below the mineral residue layer -for example, a road construction scenario -have not been taken into account, apart from two recent studies for MSWI BA and different granular secondary materials (Allegrini et al, 2015;Schwab et al, 2014). In the context of C&DW, this might be particularly critical for Cr, which has been identified as one of the elements of main concern in leachates from C&DW in relation to utilisation in construction works (Butera et al, , 2015avan der Sloot, 2000;Wahlström et al, 2000), and which has been shown to be retained by subsoils (Butera et al, 2015b).…”

Evaluating landfill aftercare strategies: A life cycle assessment approach

“…Furthermore, USEtox does not provide specific characterisation factors for emissions to groundwater. Here, these potential impacts were approximated using the characterisation factors for emissions to freshwater, an approach consistent with that of Schwab et al (2014). Based on Doka (2009), the fate of all emissions through the liner was assumed to be the groundwater receptor.…”

“…Furthermore, the results of the scenario analysis (see 3.4.2) show that, if the partitioning of emissions via Qg is split evenly between the groundwater and soil receptors (rather than 100% reaching groundwater), the potential impacts of emissions via Qg decrease substantially and the total potential impacts for S1 in the 'worst case' are greatly reduced. To minimise this uncertainty and enhance the reliability of the results, more sophisticated contaminant fate and transport modelling that considers the partitioning and speciation of emissions between and in environmental media is required (Hellweg et al, 2005;Schwab et al, 2014).…”

“…pH, redox potential, or background concentrations),which are influential in contaminant fate modelling (Hellweg et al, 2005;Pizzol et al, 2011;Plouffe et al, 2015). For micro-scale studies of particular landfill sites, the LCA approach could be complimented by the use of risk assessment techniques (Lemming et al, 2012;Schwab et al, 2014).…”