Advancing Risk Analysis for Nanoscale Materials: Report from an International Workshop on the Role of Alternative Testing Strategies for Advancement

Abstract

The Society for Risk Analysis (SRA) has a history of bringing thought leadership to topics of emerging risk. In September 2014, the SRA Emerging Nanoscale Materials Specialty Group convened an international workshop to examine the use of alternative testing strategies (ATS) for manufactured nanomaterials (NM) from a risk analysis perspective. Experts in NM environmental health and safety, human health, ecotoxicology, regulatory compliance, risk analysis, and ATS evaluated and discussed the state of the science for in vitro and other alternatives to traditional toxicology testing for NM. Based on this review, experts recommended immediate and near-term actions that would advance ATS use in NM risk assessment. Three focal areas-human health, ecological health, and exposure considerations-shaped deliberations about information needs, priorities, and the next steps required to increase confidence in and use of ATS in NM risk assessment. The deliberations revealed that ATS are now being used for screening, and that, in the near term, ATS could be developed for use in read-across or categorization decision making within certain regulatory frameworks. Participants recognized that leadership is required from within the scientific community to address basic challenges, including standardizing materials, protocols, techniques and reporting, and designing experiments relevant to real-world conditions, as well as coordination and sharing of large-scale collaborations and data. Experts agreed that it will be critical to include experimental parameters that can support the development of adverse outcome pathways. Numerous other insightful ideas for investment in ATS emerged throughout the discussions and are further highlighted in this article.

The Essential Elements of a Risk Governance Framework for Current and Future Nanotechnologies

“…Such a framework needs also to empower the broad range of stakeholders in nanotechnology governance with tools that improve practical decision making in a governance framework that is perceived by society as fair, trustworthy, and effective. Furthermore, it provides a vehicle to share and organize information, thereby improving the efficiency of risk decision making …”

Approaches to Develop Alternative Testing Strategies to Inform Human Health Risk Assessment of Nanomaterials

“…Furthermore, not all ATS will be equally applicable or useful for nanomaterial hazard identification; therefore, a need exists to prioritize ATS development. There are several ways in which prioritization could be considered, which were discussed in the context of human health and environmental risk assessment by the expert Society for Risk Analysis (SRA) workshop held in September 2014 in Washington, DC in cooperation with the Organisation for Economic Co-operation and Development (OECD) Working Party on Manufactured Nanomaterials (see Shatkin et al, 2016). For example, a systematic analysis of the current published literature allows identification of gaps in knowledge as well as areas in which there is a wealth of knowledge to draw upon.…”

“…If used alone, each test system may have limited value; however, the breadth of available ATS provides the opportunity to assess several end points simultaneously and use batteries of tests (multiple models approach), which together can provide a rich diversity of information. However, assembly of this battery of models and interpretation of the data generated by the different ATS requires an understanding of the limitations of each model, their validation by comparison to animal or human study results (e.g., via in vitro in vivo extrapolation), and the use of relevant standards to allow comparability between data sets …”

“…However, assembly of this battery of models and interpretation of the data generated by the different ATS requires an understanding of the limitations of each model, their validation by comparison to animal or human study results (e.g., via in vitro in vivo extrapolation), and the use of relevant standards to allow comparability between data sets. (3) There is an expectation that development of ATS along these lines will substantially increase the quantity of hazard information on nanomaterials and their modes of action, leading to (1) more effective and rapid screening of nanomaterials; (2) the development of in silico QSAR models facilitating a "safer by design" approach to reducing risk to human health; (3) advancement of adverse outcome pathway models; and (4) development of a tiered testing strategy for assessment of hazard with a significant reduction, though perhaps not complete elimination in the short term, of in vivo exposure and hazard testing to decrease reliance on animal models when demonstrating safety for regulatory purposes.…”

The role of alternative testing strategies in environmental risk assessment of engineered nanomaterials

“…This was discussed at a Society for Risk Analysis (SRA) workshop entitled "Nano Risk Analysis II" in Washington, D. C. (U.S.) in September 2014, with the overarching theme of how to advance risk analysis of ENMs, 3,10 and such discussion serves as the point of departure for this paper. Here we aim to describe and define the use of ATS for ENMs, and to discuss the future role of ATS in environmental risk science as applied to ENMs.…”