Chemical Alternatives Assessment Research Articles

Exposure and toxicity characterization of chemical emissions and chemicals in products: global recommendations and implementation in USEtox

PurposeReducing chemical pressure on human and environmental health is an integral part of the global sustainability agenda. Guidelines for deriving globally applicable, life cycle–based indicators are required to consistently quantify toxicity impacts from chemical emissions as well as from chemicals in consumer products. In response, we elaborate the methodological framework and present recommendations for advancing near-field/far-field exposure and toxicity characterization, and for implementing these recommendations into the scientific consensus model USEtox.MethodsAn expert taskforce was convened by the Life Cycle Initiative hosted by UN Environment to expand existing guidance for evaluating human toxicity impacts from exposure to chemical substances. This taskforce evaluated scientific advances since the original release of USEtox and identified two major aspects that required refinement, namely integrating near-field and far-field exposure, and improving human dose-response modeling. Dedicated efforts have led to a set of recommendations to address these aspects in an update of USEtox, while ensuring consistency with the boundary conditions for characterizing life cycle toxicity impacts and being aligned with recommendations from agencies that regulate chemical exposure. The proposed updated USEtox framework was tested in an illustrative rice production and consumption case study.Results and discussionOn 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. Consumer exposure is addressed via sub-models for each product type to account for product type-specific characteristics and exposure settings. Case study results illustrate that product use–related exposure dominates overall life cycle exposure. 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. This approach allows for explicitly considering both uncertainty and human variability in toxicity effect factors. Factors reflecting disease severity are proposed to distinguish cancer from non-cancer effects and within the latter to discriminate reproductive/developmental and other non-cancer effects. All proposed aspects have been consistently implemented into the original USEtox framework.ConclusionsThe recommended methodological advancements address several key limitations in earlier approaches. Next steps are to test the new characterization framework in additional case studies and to close remaining research gaps. Our framework is applicable for evaluating chemical emissions and product-related exposure in life cycle assessment, chemical alternatives assessment and chemical substitution, consumer exposure and risk screening, and high-throughput chemical prioritization.

Combining In Silico Tools with Multicriteria Analysis for Alternatives Assessment of Hazardous Chemicals: Accounting for the Transformation Products of decaBDE and Its Alternatives

Transformation products ought to be an important consideration in chemical alternatives assessment. In this study, a recently established hazard ranking tool for alternatives assessment based on in silico data and multicriteria decision analysis (MCDA) methods was further developed to include chemical transformation products. Decabromodiphenyl ether (decaBDE) and five proposed alternatives were selected as case chemicals; biotic and abiotic transformation reactions were considered using five in silico tools. A workflow was developed to select transformation products with the highest occurrence potential. The most probable transformation products of the alternative chemicals were often similarly persistent but more mobile in aquatic environments, which implies an increasing exposure potential. When persistence (P), bioaccumulation (B), mobility in the aquatic environment (M), and toxicity (T) are considered (via PBT, PMT, or PBMT composite scoring), all six flame retardants have at least one transformation product that can be considered more hazardous, across diverse MCDA. Even when considering transformation products, the considered alternatives remain less hazardous than decaBDE, though the range of hazard of the five alternatives was reduced. The least hazardous of the considered alternatives were melamine and bis(2-ethylhexyl)-tetrabromophthalate. This developed tool could be integrated within holistic alternatives assessments considering use and life cycle impacts or additionally prioritizing transformation products within (bio)monitoring screening studies.

A decision‐analytic approach to screening in chemical alternatives assessment

AbstractMaterial selection in the chemistry value chain involves consideration of many objectives, including cost, performance, health risk, and environmental impact. Alternatives assessment is an emerging tool for guiding complex decisions with respect to these goals. As a relatively new method, the process is not yet well developed, especially with respect to how trade‐offs among objectives can be assessed accurately and inexpensively. Using paint strippers alternatives assessment as an illustrative example, we show how an established decision‐analytic method, known as comparative screening, allows for a multistep process with gradually increasing information needs. Compared with existing methodological approaches, comparative screening instills flexible and consistent treatment of trade‐offs. This is important because it maximizes the potential for a robust assessment while minimizing arduous data collection. Further, its use in the alternatives assessment process can support the selection of more sustainable materials.

Building shared information infrastructure for chemical alternatives assessment

The substitution of hazardous substances with safer alternatives is being driven by policy pressures and business demands. As a result, scientific techniques for chemical alternatives assessment (CAA) have been established and communities of practice are emerging. Interest in safer chemical substitution is widely shared throughout a range of stakeholder groups across science, industry, public policy, and advocacy. Yet there is an unmet need for intentionally designed public information infrastructure to support the highly knowledge-intensive nature of CAA. We report here on the process of developing the Chemical Hazard Data Commons, an experimental project intended to support a diverse community of practitioners by providing publicly accessible chemical hazard data and tools for understanding it. In an arena where market forces and regulatory regimes have largely failed to generate the necessary knowledge, this project represents a novel application of a commons-based approach emphasizing building shared intellectual and technical capacity for CAA. The Data Commons—now a part of the related Pharos Project—includes an online portal providing simultaneous access to many different sources of information and enabling effective interactions with it. Foremost among these interactions are search and retrieval of hazard information about chemical substances, uniform display of the most relevant information, and the ability to automatically screen substances against consistent and transparent hazard-based criteria. We describe the motivation for the project and report on the principles and key considerations that guided its design as a participatory information infrastructure. We present our approach to organizing chemical information; the process of community engagement and planning; and how we constructed the system to provide functional tools. We discuss the outcomes of the project and highlight important challenges—such as fostering active participation and planning for long-term governance. With this article, we hope to inform future efforts for the collaborative development of knowledge resources for chemical alternatives assessment.

Environmental impact assessment model for substitution of hazardous substances by using life cycle approach

Regulations that are indirectly driving the substitution of hazardous chemicals, such as the EU REACH regulation, necessitate improvements in chemical alternatives assessment frameworks. In those frameworks, life cycle thinking lacks some important aspects such as systematic and quantitative occupational safety methods and risks from intermediate chemicals that are not released to the environment under normal operating conditions. Concerns of companies about regulatory drivers regarding substances of very high concern often lead to inadequate evaluation of the baseline situation; an issue also overlooked by the frameworks. Moreover, life cycle assessment is optional for assessors with limited resources, such as small and medium enterprises. However, the success of substitution should not be evaluated without life cycle concerns. An environmental impact assessment model has been suggested to overcome these shortcomings of the chemical alternatives assessment frameworks. The model was applied to a case study of primed metal sheet production, where the company was driven to substitute reprotoxic 2-methoxypropanol used in their formulations. The results show that the proposed model is promising for solving the mentioned shortcomings, informing the assessor about substances of very high concern along the life cycle, and it has the potential to be further improved with the help of supporting software and databases. Particularly, in the occupational safety area that concerns risks of accidents at work, improvements to the EU occupational health database can drastically increase the accuracy of the assessments. Besides, the development of methodologies for the quantification of the impacts of reprotoxic, bioaccumulative and endocrine disruptor substances is necessary.

Chemical alternatives assessment of selected low aromatic C7–C18 isoparaffin solvents, a class of UVCB substances

Chemical alternatives assessment of selected low aromatic C7–C18 isoparaffin solvents, a class of UVCB substances

Facing the rain after the phase out: Performance evaluation of alternative fluorinated and non-fluorinated durable water repellents for outdoor fabrics

Fluorinated durable water repellent (DWR) agents are used to obtain water and stain repellent textiles. Due to the on-going phase-out of DWRs based on side-chain fluorinated polymers (SFP) with “long” perfluoroalkyl chains, the textile industry lacks suitable alternatives with comparable material characteristics. The constant development and optimization of SFPs for textile applications initiated more than half a century ago has resulted in a robust and very efficient DWR-technology and textiles with exceptional hydro- and oleo-phobic properties. The industry is now in the predicament that the long-chain SFPs with the best technical performance have undesirable toxicological and environmental behaviour. This study provides a comprehensive overview of the technical performance of presently available fluorinated and non-fluorinated DWRs as part of a chemical alternatives assessment (CAA). The results are based on a study with synthetic outdoor fabrics treated with alternative DWRs and tested for repellency using industrial standard and complementary methods. Using this approach, the complex structure-property relationships of DWR-polymers could be explained on a molecular level. Both short-chain SFPs and non-fluorinated DWRs showed excellent water repellency and durability in some cases while short-chain SFPs were the more robust of the alternatives to long-chain SFPs. A strong decline in oil repellency and durability with perfluoroalkyl chain length was shown for SFP DWRs. Non-fluorinated alternatives were unable to repel oil, which might limit their potential for substitution in textile application that require repellency towards non-polar liquids.

Approaches to chemical alternatives assessment (CAA) for the substitution of hazardous substances in small- and medium-sized enterprises (SMEs)

Six alternatives assessment frameworks have been reviewed for specific features that might affect the implementation of alternatives assessment and cause regrettable substitution. These features are: the assessments included, the assessment flowchart structure, the inclusion of the assessors with limited resources (e.g., SMEs) in terms of resource intensity, the tools and methods included or guided to, and the indicators. The purpose of this review was to point out the existing important differences among the frameworks and also to stress the possibility of future improvements for the application of frameworks in SMEs. In general, it has been determined that, although there are similar features (e.g., hazard assessment methods) among the reviewed frameworks, there are also serious differences that might affect the assessment outcome, such as the use of physicochemical properties, the scope of life cycle thinking, and decision methods. These differences are caused by the exclusion of particular assessments, as well as the differences among the assessment methods used and the flowchart structure of the framework that incorporates these assessments. Ideally, the frameworks should give the same results under the same circumstances. Also, frameworks usually ignore the follow-up stage of the alternatives assessment, which is an important shortcoming of the frameworks. Common approaches, such as the exclusion of assessments or the use of the sequential elimination method seem to be a temporary solution to the existing problem of the implementation of these frameworks by SMEs. Common principles and methods should be in place to be able to minimize those differences among frameworks toward an optimized framework that enables assessors with limited resources to conduct a comprehensive assessment that is necessary to avoid a regrettable substitution.

Aiding alternatives assessment with an uncertainty-tolerant hazard scoring method

This research developed a single-score system to simplify and clarify decision-making in chemical alternatives assessment, accounting for uncertainty. Today, assessing alternatives to hazardous constituent chemicals is a difficult task—rather than comparing alternatives by a single definitive score, many independent toxicological variables must be considered at once, and data gaps are rampant. Thus, most hazard assessments are only comprehensible to toxicologists, but business leaders and politicians need simple scores to make decisions. In addition, they must balance hazard against other considerations, such as product functionality, and they must be aware of the high degrees of uncertainty in chemical hazard data. This research proposes a transparent, reproducible method to translate eighteen hazard endpoints into a simple numeric score with quantified uncertainty, alongside a similar product functionality score, to aid decisions between alternative products. The scoring method uses Clean Production Action's GreenScreen as a guide, but with a different method of score aggregation. It provides finer differentiation between scores than GreenScreen's four-point scale, and it displays uncertainty quantitatively in the final score. Displaying uncertainty also illustrates which alternatives are early in product development versus well-defined commercial products. This paper tested the proposed assessment method through a case study in the building industry, assessing alternatives to spray polyurethane foam insulation containing methylene diphenyl diisocyanate (MDI). The new hazard scoring method successfully identified trade-offs between different alternatives, showing finer resolution than GreenScreen Benchmarking. Sensitivity analysis showed that different weighting schemes in hazard scores had almost no effect on alternatives ranking, compared to uncertainty from data gaps.

Coupled near-field and far-field exposure assessment framework for chemicals in consumer products

Humans can be exposed to chemicals in consumer products through product use and environmental emissions over the product life cycle. Exposure pathways are often complex, where chemicals can transfer directly from products to humans during use or exchange between various indoor and outdoor compartments until sub-fractions reach humans. To consistently evaluate exposure pathways along product life cycles, a flexible mass balance-based assessment framework is presented structuring multimedia chemical transfers in a matrix of direct inter-compartmental transfer fractions. By matrix inversion, we quantify cumulative multimedia transfer fractions and exposure pathway-specific product intake fractions defined as chemical mass taken in by humans per unit mass of chemical in a product. Combining product intake fractions with chemical mass in the product yields intake estimates for use in life cycle impact assessment and chemical alternatives assessment, or daily intake doses for use in risk-based assessment and high-throughput screening. Two illustrative examples of chemicals used in personal care products and flooring materials demonstrate how this matrix-based framework offers a consistent and efficient way to rapidly compare exposure pathways for adult and child users and for the general population. This framework constitutes a user-friendly approach to develop, compare and interpret multiple human exposure scenarios in a coupled system of near-field (‘user’ environment), far-field and human intake compartments, and helps understand the contribution of individual pathways to overall human exposure in various product application contexts to inform decisions in different science-policy fields for which exposure quantification is relevant.

The applicability of chemical alternatives assessment for engineered nanomaterials.

The use of alternatives assessment to substitute hazardous chemicals with inherently safer options is gaining momentum worldwide as a legislative and corporate strategy to minimize consumer, occupational, and environmental risks. Engineered nanomaterials represent an interesting case for alternatives assessment approaches, because they can be considered both emerging "chemicals" of concern, as well as potentially safer alternatives to hazardous chemicals. However, comparing the hazards of nanomaterials to traditional chemicals or to other nanomaterials is challenging, and critical elements in chemical hazard and exposure assessment may have to be fundamentally altered to sufficiently address nanomaterials. The aim of this paper is to assess the overall applicability of alternatives assessment methods for nanomaterials and to outline recommendations to enhance their use in this context. The present paper focuses on the adaptability of existing hazard and exposure assessment approaches to engineered nanomaterials as well as strategies to design inherently safer nanomaterials. We argue that alternatives assessment for nanomaterials is complicated by the sheer number of nanomaterials possible. As a result, the inclusion of new data tools that can efficiently and effectively evaluate nanomaterials as substitutes is needed to strengthen the alternatives assessment process. However, we conclude that with additional tools to enhance traditional hazard and exposure assessment modules of alternatives assessment, such as the use of mechanistic toxicity screens and control banding tools, alternatives assessment can be adapted to evaluate engineered nanomaterials as potential substitutes for chemicals of concern and to ensure safer nanomaterials are incorporated in the design of new products. Integr Environ Assess Manag 2017;13:177-187. © 2016 SETAC.

The Architecture of Chemical Alternatives Assessment.

Chemical alternatives assessment is a method rapidly developing for use by businesses, governments, and nongovernment organizations seeking to substitute chemicals of concern in production processes and products. Chemical alternatives assessment is defined as a process for identifying, comparing, and selecting safer alternatives to chemicals of concern (including those in materials, processes, or technologies) on the basis of their hazards, performance, and economic viability. The process is intended to provide guidance for assuring that chemicals of concern are replaced with safer alternatives that are not likely to be later regretted. Conceptually, the assessment methods are developed from a set of three foundational pillars and five common principles. Based on a number of emerging alternatives assessment initiatives, in this commentary, we outline a chemical alternatives assessment blueprint structured around three broad steps: Scope, Assessment, and Selection and Implementation. Specific tasks and tools are identified for each of these three steps. While it is recognized that on-going practice will further refine and develop the method and tools, it is important that the structure of the assessment process remain flexible, adaptive, and focused on the substitution of chemicals of concern with safer alternatives.

Defining and defending risk: conceptual risk formulas in environmental controversies

Environmental risks are contested topics, and definitions of risk often vary across contexts, disciplines, and institutions. Identifying and describing differences between risk definitions is particularly important because they directly impact risk assessment and management practices. This paper describes how stakeholders rhetorically define and technically operationalize the risks of industrial chemicals, focusing on contemporary debates over flame retardant chemicals that in recent years have been the subject of numerous risk assessments, regulatory activities, and activist campaigns. This paper uses a multi-method approach to develop six conceptual risk formulas which delineate the components that go into evaluating risk and the relationships between those components: the classic risk formula, the emerging toxicology risk formula, the exposure-proxy risk formula, the exposure-centric risk formula, the hazard-centric risk formula, and the either-or risk formula. Using chemical alternatives assessment as an example, this analysis demonstrates how conceptual risk definitions influence the operationalization of risk assessment and management activities.

From incremental to fundamental substitution in chemical alternatives assessment

Several chemicals in consumer products are subject to binding or voluntary phase-out agreements that are based on international treaties such as the Stockholm Convention on Persistent Organic Pollutants or on regulatory frameworks such as the European Union's Registration, Evaluation, Authorization and Restriction of Chemicals (REACH). To facilitate a phase-out process, alternatives assessment is commonly applied as an emerging approach to identifying chemicals (or materials, processes, and behavior changes) serving as substitutes. Polybrominated diphenyl ethers (PBDEs), long-chain poly- and perfluorinated alkyl substances (PFASs), and polychlorinated biphenyls (PCBs) are well-known cases of chemicals where substitution processes can be studied. Currently, there are various challenges in assessing, evaluating and effectively introducing chemical alternatives. These challenges are mainly related to similarity in chemical structures and, hence, similar hazard profiles between phase-out and substitute chemicals, leading to a rather incremental than fundamental substitution. A hampered phase-out process, the lack of implementing Green Chemistry principles in chemicals design, and lack of Sustainable Chemistry aspects in industrial processes design constitute additional challenges. We illustrate the various challenges in the process of phasing out and successfully substituting hazardous chemicals in consumer products and provide guiding principles for addressing these challenges. We propose an integrated approach of all stakeholders involved toward more fundamental and function-based substitution by greener and more sustainable alternatives. Our recommendations finally constitute a starting point for identifying further research needs and for improving current alternatives assessment practice.

Chemical alternatives assessment: The case of flame retardants

Decisions on chemical substitution are made rapidly and by many stakeholders; these decisions may have a direct impact on consumer exposures, and, when a hazard exists, to consumer risks. Flame retardants (FRs) represent particular challenges, including very high production volumes, designed-in persistence, and often direct consumer exposure. Newer FR products, as with other industrial chemicals, typically lack data on hazard and exposure, and in many cases even basic information on structure and use in products is unknown. Chemical alternatives assessment (CAA) provides a hazard-focused approach to distinguishing between possible substitutions; variations on this process are used by several government and numerous corporate entities. By grouping chemicals according to functional use, some information on exposure potential can be inferred, allowing for decisions based on those hazard properties that are most distinguishing. This approach can help prevent the “regrettable substitution” of one chemical with another of equal, or even higher, risk.

Chemical Alternatives Assessment: Enabling Substitution to Safer Chemicals

Chemical Alternatives Assessment: Enabling Substitution to Safer Chemicals

Chemical Alternatives Assessment: Enabling Substitution to Safer Chemicals

As potentially or actually harmful ingredients are identified in commercial products, the goal is to replace them with safer alternatives. Yet a chemical ingredient is hardly a modular component that can be easily switched out. Further, replacement could remove one hazard and introduce others. To avoid this stymieing problem and ease an innovator’s choice of ingredients, Lavoie et al. report on a decision-making approach developed by the EPA’s Design for Environment program. A few case experiences illustrate its utility and recommend further use.