Human Toxicological Impacts in Life Cycle Assessment of Circular Economy of the Built Environment: A Case Study of Denmark

Caroline Wielandt Egemose,Joshua L Sohn,Xavier Fretté,Morten Birkved,Diane Bastien

doi:10.3390/buildings12020130

Caroline Wielandt Egemose, Joshua L Sohn + Show 3 more

Open Access

https://doi.org/10.3390/buildings12020130

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Abstract

The circular economy has become an important topic in the building industry, and life cycle assessment (LCA) is often used to quantify its benefits. Through chemical analysis, this article demonstrates that the current LCA is not yet well-adapted to assess the circular economy of building materials and components. It is shown that current inventory data and models are insufficient because they do not consider the uptake and emission of chemicals during use, the migration of chemicals within the value chain across the multiple phases in the circular economy, and because current characterization models lack a large fraction of the potentially emitted chemicals from said uptake and emission identified in the tested building material samples. Thus, it is shown that impacts relevant for LCA in the circular economy of buildings remain unaddressed because they are currently either omitted in the LCA that covers a limited number of impact indicators, or are ostensibly covered in the LCA covering a full set of indicators but missed due to inadequate characterization models. To ameliorate this, a definition of embedded toxicity and its relationship to the toxicological footprint is presented and a method for measurement is proposed, illustrating how assessing embedded toxicity can yield information for facilitating safe building-material reuse. Finally, a suggestion for the improvement of life cycle impact assessment methods is proposed.

Highlights

In the built environment, conventional life cycle assessment (LCA) can be used to assess the environmental impacts of building materials from cradle-to-grave in order to assist in the selection of materials, components, and designs based on environmental performance indicators [1]
It is striking that characterization factors for quantification of human toxicological impact potentials have only been identified for 5 out of the 18 chemicals identified during the experimental analyzes developed for assessing embedded toxicity
Considering that the human indoor exposure during the use phase of a building material/component is only rarely taken into account no matter what LCA methodology applied, our results indicate that this omission should be a priority with regard to future research, as the use phase has the potential to contribute significantly to the total human toxicological impacts of these building materials

Summary

Introduction

Conventional life cycle assessment (LCA) can be used to assess the environmental impacts of building materials from cradle-to-grave in order to assist in the selection of materials, components, and designs based on environmental performance indicators [1]. Conventional LCA, as applied within the built environment, was developed for the assessment of product systems following a linear economic life cycle (i.e., production, use, and disposal of material) [2]. In relation to the topic of this discussion, the building industry is moving towards a circular economy [4]. This shift requires prioritization based on environmental and performance criteria to ensure that materials/components for the built environment are chosen while considering both previous and future uses for optimizing their environmental performance

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