Discussion Session 8 | Life Cycle Innovation in the Chemical Sector

Presenter

[youzer_author_box user_id=”6093″ layout=’yzb-author-v5′ networks_type=”colorful” networks_format=”flat”]

Co-Author:

Peter Fantke

Abstract

Introduction: Biochemicals are in many cases a suitable alternative to petrochemicals, in line with global policy targets to boost a green transition and build a viable bioeconomy. However, producing chemicals from bio-feedstocks does not automatically ensure their environmental sustainability or – in cases – even better sustainability performance than petrochemicals. To address this challenge, we need to understand the sustainability performance of biochemicals when compared to functionally equivalent petrochemicals, assess the environmental hotspots of different biochemicals over their entire life cycle, and identify relevant trade-offs between environmental and economic sustainability at an early stage of development.
Methods: Building on existing studies, we evaluated reported environmental sustainability performance for main building block biochemicals against the performance of functionally equivalent petrochemicals. Then, we developed a systematic framework for assessing the life cycle environmental impacts of lactic acid production systems using different bio-feedstock generations, to identify feedstock-specific impact hotspots. Finally, we combine indicators for environmental sustainability with techno-economic performance in a consistent framework to support overall optimization of biochemical production systems.
Results: Comparing environmental sustainability performance of biochemicals and functionally equivalent petrochemicals reveals that biochemicals can perform better or worse across various impact categories. Where biochemicals can show higher impacts than petrochemical equivalents are mainly land use impacts (feedstock production, end-of-life treatment), particulate matter formation (refining), and even global warming impacts (polymerization, end-of-life treatment) [1]. Comparing environmental performance of biochemical production systems for lactic acid shows that feedstock production and biorefinery processes dominate overall impacts, while each feedstock generation has its own impact hotspots, e.g. biomass drying dominating impact profiles when using macroalgae as feedstock [2]. Finally, combining environmental with techno-economic performance demonstrates that there are significant trade-offs; hence, an overall performance optimization requires the consideration of both aspects.
Conclusions: We recommend to systematically incorporate environmental sustainability performance for optimizing biochemical production systems, building on the broader set of impact categories and all life cycle stages. We further recommend to focus on the hotspots within each feedstock generation. Finally, we recommend to align environmental and economic performance to address relevant tradeoffs. This will help to overall optimizing biochemical production systems in support of boosting a viable and sustainable bioeconomy, and contributing to meeting local-to-global targets for sustainable development that are aligned with ecological capacities for chemical pollution [3].

References:

[1] Ögmundarson Ó, Herrgård MJ, Förster J, Hauschild MZ, Fantke P, 2020. Addressing environmental sustainability of biochemicals. Nat Sustain, in press
[2] Ögmundarson Ó, Sukumara S, Laurent A, Fantke P, 2020. Environmental hotspots of different lactic acid production systems. GCB Bioenergy 12:19-38
[3] Fantke P, Illner N, 2019. Goods that are good enough: Introducing an absolute sustainability perspective for managing chemicals in consumer products. Curr Opin Green Sustain Chem 15:91-97

Presenter

[youzer_author_box user_id=”114″ layout=’yzb-author-v5′ networks_type=”colorful” networks_format=”flat”]

Co-Authors

Neil Brown

Benjamin Coleman

Abstract

The accumulation of plastics waste in the environment is a complex problem that has captured the attention of consumers, regulatory agencies, and corporations. It is also a problem that is not easily addressed by current mechanical recycling and waste management. To address this issue, companies must demonstrate meaningful commitments for transition of their product portfolios from “take, make, dispose” models to those that contribute to a truly Circular Economy. Eastman has recently announced investments in two distinct chemical recycling technologies: Polyester Renewal Technology and Carbon Renewal Technology. These two chemical recycling technologies position Eastman to feed waste plastic materials to its manufacturing facilities. In addition to investing in the chemical recycling technologies themselves, Eastman has achieved third party certification for a mass balance accounting methodology, thereby allowing both of these technologies to advance the Circular Economy in meaningful ways. Furthermore, Eastman recognizes the potential for environmental tradeoffs and therefore has conducted, and received third party certification for, Life Cycle Assessments (LCAs) of these chemical recycling technologies. Eastman’s presentation will review the chemical recycling technologies, the relevant resulting environmental impacts from the LCAs, and discuss how LCA can contribute to the ongoing conversation around the development of circularity initiatives.

Presenter

[youzer_author_box user_id=”6077″ layout=’yzb-author-v5′ networks_type=”colorful” networks_format=”flat”]

Co-Authors

Peter Fantke

Lei Huang

Olivier Jolliet

Abstract

Introduction: Numerous chemicals are used as additives in plastics, including toys, fulfilling certain functions, such as plasticizers, flame-retardants, or colorants. However, several additives may pose risks to children via various exposure pathways. Moreover, in recycled plastics supporting a circular economy, several additive residuals can end up in recyclates, leading to additional exposures [1]. The combination of harmful additives and residues constitute a challenge to be urgently addressed for implementing a circular economy for plastics [2]. Key is the identification of priority chemicals targeted for reduced use in virgin and recycled plastic toys.
Methods: We identify chemicals reported to occur in virgin and recycled plastic toys. For these chemicals, we combine concentrations in plastics with toy consumption data. We then estimate related cancer and non-cancer risks for children by adapting a high-throughput exposure framework combined with toxicity information [3, 4]. From raking the risks, we produce prioritization lists of chemicals in toys, determine the contribution of possible residues from previous uses, and compare our results with other lists.
Results: Children’s risks from exposure to chemicals in plastic toys are dominated by additives (mainly phthalate plasticizers and some brominated flame-retardants), with cancer and non-cancer risks exceeding acceptable levels for multiple chemicals. Risks from residues in recycled toys are substantially lower and often negligible. While some of our priority chemicals appear in other lists, we also identified additional priority chemicals that are not yet covered elsewhere and require further attention. For ensuring full coverage and reduce uncertainty, it is key to obtain high-quality and comprehensive data on chemical content in plastics and recyclates, and to ensure the applicability to other chemical classes, e.g. metals.
Conclusions: We recommend deriving maximum allowable concentrations for hazardous chemicals in toys, to ensure that both remaining cancer and non-cancer risks are below acceptable risk levels for children. This will enable producers to test whether a certain grade of recycled plastic is usable for toys manufacturing. Chemical ingredients, such as some plasticizers, whose effective content at which they fulfil their function is above these maximum allowable concentrations, should be avoided or possibly banned when also reported in other priority lists, or further scrutinized otherwise. Our approach can help identify priority chemicals also in other products (e.g. food contact and building materials) and should be applied to screen chemicals already in material design [5], to boost a viable circular economy for plastic toys.

References:

[1] Ionas AC, Dirtu AC, Anthonissen T, Neels H, Covaci A, 2014. Downsides of the recycling process: Harmful organic chemicals in children’s toys. Environ Int 65:54-62
[2] Fantke P, Illner N, 2019. Goods that are good enough: Introducing an absolute sustainability perspective for managing chemicals in consumer products. Curr Opin Green Sustain Chem 15:91-97
[3] Fantke P, Ernstoff AS, Huang L, Csiszar SA, Jolliet O, 2016. Coupled near-field and far-field exposure assessment framework for chemicals in consumer products. Environ Int 94:508-518
[4] Aurisano N, Huang L, Jolliet O, Mila i Canals L, Fantke P, 2020. Chemicals of concern in plastic toys. Environ Sci Technol (submitted)
[5] Fantke P, Weber R, Scheringer M, 2015. From incremental to fundamental substitution in chemical alternatives assessment. Sustain Chem Pharm 1:1-8

Presenter

[youzer_author_box user_id=”6007″ layout=’yzb-author-v5′ networks_type=”colorful” networks_format=”flat”]

Co-Authors

Michael Overcash

Lei Huang

Olivier Jolliet

Abstract

Background: Life cycle assessment (LCA) aims at identifying optimal environmental performance of products and systems, while chemical alternatives assessment (CAA) aims at substituting harmful chemicals in products. Human exposure and toxicity are important components in both, yet they only focus on selected elements or sum up inconsistent metrics, which leaves relevant exposure-related trade-offs unaddressed, potentially leading to misleading decisions across product and chemical comparisons [1]. These trade-offs occur particularly between exposure to various chemicals during use of multiple consumer products, and exposure to environmental emissions along entire chemical and product life cycles. To close this gap, consumer exposure and emission-based exposures need to be consistently integrated and combined with toxicity impacts.
Methodology: Following latest recommendations from the UNEP/SETAC Life Cycle Initiative, we propose a quantitative, high-throughput framework, coupling near-field consumer exposures with emission-based far-field population exposures in a single mass-balance, and link exposures consistently to an adapted, consensus-based, probabilistic approach for characterizing toxicity [2]. Our framework uses the product intake fraction (PiF) metric as reference for comparing exposure pathways and populations on the basis of chemical mass in products [3], builds on and is fully compatible with the scientific consensus model USEtox (usetox.org), and incorporates latest WHO recommendations for non-linear human toxicity modelling under uncertainty [4]. It finally summarizes mechanistically-based results into easily interpretable comparative impact scores, expressed on a log-scale (like 1 to 10).
Results: Applying our framework in an LCA on rice production, we demonstrate that phthalate plasticizers found in rice packaging lead to consumer exposures that dominate overall life cycle toxicity impacts, being 2 orders of magnitude higher than cradle-to-gate population impacts. Applying the same framework to substitute for example the hazardous plasticizer DEHP, using in part the EGIP database to derive mass-balanced chemical supply chain emissions [5], yielded up to a factor 30 lower toxicity impacts for the non-phthalate plasticizers DEHA and 97A based on also considering exposures over the entire chemical and product supply chains. Our results illustrate the importance and feasibility to quantitatively integrate consumer and population impacts on a consistent mass-balance basis, allowing for an appropriate comparison of all contributing pathways, as well as to transparently identify suitable alternatives to harmful chemicals in consumer products.
Conclusions: As data and models for consumer exposure become more and more available, this USEtox-compatible approach constitutes an appropriate basis for characterizing human toxicity impacts from both consumer and population exposures, for use in LCA and chemical substitution.

References:

[1] Fantke P, et al. 2018. Advancements in life cycle human exposure and toxicity characterization. Environ Health Perspect 126:125001
[2] Global Guidance on Environmental Life Cycle Impact Assessment Indicators: Vol 2, Chapter 4: Human Toxicity. UNEP/SETAC Life Cycle Initiative, 2019. Paris, France, pp. 80-103
[3] Fantke P, et al. 2016. Coupled near-field and far-field exposure assessment framework for chemicals in consumer products. Environ Int 94:508-518
[4] Guidance document on evaluating and expressing uncertainty in hazard characterization. World Health Organization, Geneva, Switzerland
[5] Overcash M, 2016. Environmental genome of industrial products (EGIP): The missing link for human health. Green Chem 18:3600-3606