USES-LCA 2.0—a global nested multi-media fate, exposure, and effects model

Abstract

1 The USES-LCA 2.0 modelThe Uniform System for the Evaluation of Substancesadapted for LCA purposes, in short USES-LCA, is a multi-media fate, exposure, and effects model (Huijbregts et al.2000). The model USES-LCA is based on the (E)USESmodel family applied for risk assessment purposes in theEuropean Union (Vermeire et al. 2005). It is one of themodels involved in the development of LCIA toxicityconsensus model USEtox (Rosenbaum et al. 2008). USES-LCA has recently been updated to USES-LCA 2.0 andcontains a database of 3,396 chemicals. With this version,the user has now access to an easy-to-use model thatcalculates characterization factors for ecotoxicity andhuman toxicity on both the midpoint and endpoint level.For human toxicity, characterization factors for carcino-gens, for non-carcinogens, and overall characterizationfactors are provided. Separate ecotoxicological character-ization factors are provided for terrestrial, freshwater, andmarine ecosystems. To obtain an overall ecotoxicologicalcharacterization factor on endpoint level, they are furtheraggregated on the basis of species density of terrestrial,freshwater, and marine ecosystems separately. Figure 1gives a schematic overview of USES-LCA 2.0.Compared to consensus model USEtox, the main extrafeatures of USES-LCA are (a) next to midpoint character-ization factors, endpoint characterization factors are alsocalculated; (b) next to freshwater ecotoxicity, seawater andterrestrial ecotoxicity are also addressed; and (c) variousscenario assumptions can be tested by changing scenariosettings (further details described below).This note summarizes the USES-LCA 2.0 model asdeveloped from the junction of the individual fate andintake part (Huijbregts et al. 2005b), human toxicologicalpart (Huijbregts et al. 2005a), and ecotoxicological part(Van de Meent and Huijbregts 2005; Van Zelm et al. 2007;Van Zelm et al. 2009). Any further information on thecalculation of the separate parts of the characterizationfactors can be found in these articles.2 Fate and exposure factorsFor ten emission compartments, including urban air, rural air,freshwater,andagriculturalsoil,USES-LCA2.0calculatesbydefault environmental fate and exposure factors in multiplecompartmentsandhumanintakefactorsforinhalationandoralintake using an infinite time horizon. Environmental fate andexposure factors express the change in the dissolved concen-tration in an environmental compartment due to an emissionchange. Human intake factors express the change in exposureof the total human population at continental, moderate, arctic,or tropic scale via ingestion, or inhalation due to an emissionchange in a compartment. Rain–no rain conditions areimplemented in USES-LCA 2.0 according to the intermittentrain model as outlined by Jolliet and Hauschild (2005).Due to the large uncertainty of modeling metal behaviorin the environment, USES-LCA 2.0 includes the possibilityto test the sensitivity of the metal characterization factorsaccording to the following user-specific scenario options:1. Oral intake via food by humans can be excluded for allmetals, as it has been shown that the concept ofbioconcentration, generally applicable for organic pollu-