Advancements in Life Cycle Human Exposure and Toxicity Characterization

Abstract

Background: The Life Cycle Initiative, hosted at the United Nations Environment Programme, selected human toxicity impacts from exposure to chemical substances as an impact category that requires global guidance to overcome current assessment challenges. The initiative leadership established the Human Toxicity Task Force to develop guidance on assessing human exposure and toxicity impacts. Based on input gathered at three workshops addressing the main current scientific challenges and questions, the task force built a roadmap for advancing human toxicity characterization, primarily for use in life cycle impact assessment (LCIA). Objectives: The present paper aims at reporting on the outcomes of the task force workshops along with interpretation of how these outcomes will impact the practice and reliability of toxicity characterization. The task force thereby focuses on two major issues that emerged from the workshops, namely considering near-field exposures and improving dose–response modeling. Discussion: The task force recommended approaches to improve the assessment of human exposure, including capturing missing exposure settings and human receptor pathways by coupling additional fate and exposure processes in consumer and occupational environments (near field) with existing processes in outdoor environments (far field). To quantify overall aggregate exposure, the task force suggested that environments be coupled using a consistent set of quantified chemical mass fractions transferred among environmental compartments. With respect to dose–response, the task force was concerned about the way LCIA currently characterizes human toxicity effects, and discussed several potential solutions. A specific concern is the use of a (linear) dose–response extrapolation to zero. Another concern addresses the challenge of identifying a metric for human toxicity impacts that is aligned with the spatiotemporal resolution of present LCIA methodology, yet is adequate to indicate health impact potential. Conclusions: Further research efforts are required based on our proposed set of recommendations for improving the characterization of human exposure and toxicity impacts in LCIA and other comparative assessment frameworks. https://doi.org/10.1289/EHP3871

Towards integrating toxicity characterization into environmental studies: case study of bromine in soils

“…Quantifying life cycle toxicity impacts based on existing actual pollutant levels in soil will, in addition, be useful in complementing pollutant threshold levels by uncovering potential tradeoffs between different multi-media fates and multipathway exposures, related to soil contaminants contributing to potentially negative impacts on humans and the environment (Fantke et al 2018a(Fantke et al , 2018b. In the present study, we focus on the following three objectives: (1) to determine the cumulative mass of bromine in soil in the different districts of Tomsk oblast and discuss potential sources; (2) to characterize cumulative human toxicity and ecotoxicity impact potentials of bromine mass in soils of Tomsk oblast; and (3) to identify existing challenges of combining environmental studies with screeninglevel toxicity characterization, and to discuss future research needs as input to develop operational methods for mitigating contamination from emissions of inorganic substances.…”

Life cycle based alternatives assessment (LCAA) for chemical substitution

“…For toxicity-related impacts, we used the scientific consensus model USEtox, 49 which is widely used in comparative assessments. 58,59 For ecotoxicity, species loss is expressed as potentially disappeared fraction (PDF) of ecosystem species exposed over a given time and freshwater volume per unit mass emitted. 60,61 For human toxicity and exposure to fine particulate matter, lifetime loss is expressed as disabilityadjusted life years (DALY), 62,63 consistently combining for the latter information for population exposure 64 and exposureresponse slopes.…”

Building a European exposure science strategy

“…Compared with toxicology, however, exposure science is still ill developed as an independent discipline [2,4]. Yet, it has become an indispensable element in various science and policy frameworks, from policy analysis to sustainability assessment [5][6][7][8][9][10][11][12][13], and has been proposed as an important component in chemical substitution [14,15]. Although many regulations and studies focus on exposure to chemicals, assessing and managing exposure to other stressors is increasingly acknowledged.…”

“…To identify such key needs, two surveys were developed targeting exposure science professionals representing a wide spectrum of stakeholders. The first survey was conducted in 2016 and sent to all 560 participants attending the ISES 26 th Annual Meeting, [9][10][11][12][13] October, in Utrecht, The Netherlands. Participants were asked to provide their visions for exposure science in Europe in five and ten years, to identify the main drivers for exposure science, and how they see the role of a European chapter of ISES for improving exposure information and its policy uptake.…”