Another specific need is the improvement of dose-response assessment for non-cancer toxicity that would benefit from latest progress in stochastic dose-response modelling ( WHO 2014, 2017, Chiu & Slob 2015, WHO 2017, Chiu et al. Hence, including pathways related to chemicals in consumer products into the original LCIA framework is crucial for considering all relevant life cycle toxicity impacts. 2016, Fantke & Jolliet 2016, Csiszar et al. Furthermore, a series of recent studies has demonstrated that environmentally-mediated exposures from chemical emissions are less important for overall exposure than consumer exposure to chemical constituents in products ( Shin et al. 2018a, b, Kirchhübel & Fantke 2019, Crenna et al. Such improvements are mainly related to increasing the spatiotemporal and population-level resolution of impact estimates and extending the coverage and quality of substance, exposure, and dose-response data and models ( Fantke et al. 2008), the original toxicity characterization framework has limitations, calling for further improvement based on scientific progress. However, despite reflecting-as a scientific consensus model-mature science ( Hauschild et al. It includes inhalation and ingestion exposure, and related health effects from emissions into far-field compartments (air, water, soil) or into a generic indoor compartment. Current practice for characterizing human toxicity and freshwater ecotoxicity impacts in LCIA is implemented in this model. In response to these needs, the Life Cycle Initiative, which is hosted at the UN Environment Programme, developed and endorsed the scientific consensus model USEtox ( Rosenbaum et al. 2018a), while being aligned with chemicals-management recommendations from regulatory entities ( Saouter et al. Therefore, it is important that related recommendations are consistent with the boundary conditions of characterizing toxicity impacts in life cycle impact assessment (LCIA) ( Fantke et al. ![]() Such guidelines should focus especially on providing recommendations for globally applicable and life-cycle-based indicators and underlying methods that are most suitable for the quantitative characterization of human and ecological toxicity impacts associated with chemical emissions and exposure. Harmonized guidelines are required to consistently quantify life cycle toxicity impacts from chemical emissions as well as from exposure to chemicals in products or articles (hereafter referred to as ‘products’). This includes the reduction of chemical emissions into the natural environment along product life cycles as well as the reduction of human exposure to chemicals used in consumer goods, as laid out in the United Nations (UN) Sustainable Development Goals ( UN 2020) and in the UN Environment Programme’s Strategic Approach to International Chemicals Management ( UNEP 2015). Reducing chemical pressure on human and ecological health is an integral part of the global sustainability agenda. All proposed aspects have been consistently implemented into the original USEtox framework. Factors reflecting disease severity are proposed to distinguish cancer from non-cancer effects, and within the latter discriminate reproductive/developmental and other non-cancer effects. This approach allows for explicitly considering both uncertainty and human variability in effect factors. ![]() On the effect side, a probabilistic dose-response approach combined with a decision tree for identifying reliable points of departure is proposed for non-cancer effects, following recent guidance from the World Health Organization. Case study results illustrate that product-use related exposure dominates overall life cycle exposure. Consumer exposure is addressed via submodels for each product type to account for product characteristics and exposure settings. On the exposure side, a matrix system is proposed and recommended to integrate far-field exposure from environmental emissions with near-field exposure from chemicals in various consumer product types.
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