Society For Risk Analysis Annual Meeting 2012

Advancing Analysis

Session Schedule & Abstracts

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Common abbreviations

Symposium: Ready for Prime Time? The Role of High Through-Put Screening in Risk Assessment for Engineered Nanomaterials

Room: Pacific Concourse K   10:30 AM - Noon

Chair(s): Jo Ann Shatkin

Sponsored by ENMSG

One of the difficulties in assessing the risks of engineered nanomaterials (ENM) is the lack of validated methods for predicting biological and environmental behavior in complex systems. To date, there has been little correlation between in vivo studies of ENM and in vitro assays, slowing the development of data sets for risk assessment and regulatory decision making. Methods under development at the Center for Environmental Implications of Nanotechnology for high throughput screening look promising in terms of correlation, however these data have not been used in risk assessments. This symposium will gather experts to examine the state of high throughput screening method development, and address the question of whether these methods are robust for assessing health and environmental risks of ENM. Two speakers from the NSF Center for Environmental Implications, Professor Yoram Cohen, and Professor Hilary Godwin, will present the data, and explain their implications for risk assessment. The talks will be followed by a roundtable discussion with experts offering their views from governmental, industry, and risk perspectives on the state of the science and its maturity for decision making regarding the risks of emerging nanoscale materials. Moderator: Jo Anne Shatkin, CLF Ventures, Inc. Speakers: Hilary Godwin, CEIN High-throughput screening: a transformative approach to nanotoxicology Yoram Cohen, UCLA Development of Environmental Impact Assessment Models for Engineered Nanomaterials Discussants: Sally Tinkle; NNCO (governmental perspective) Richard Pleus, Intertox (informatics, nanotoxicology and risk assessment perspective) Fred Klaessig, Pennsylvania Bio Nano Systems, LLC (industry Perspective)

M2-B.1  10:30  Development of Environmental Impact Assessment Models for Engineered Nanomaterial. Cohen Y*, Liu H, Liu R, Rallo R, Godwin H, Nel A; University of California, Los Angeles

Abstract: Assessment of the environmental impact of engineered nanomaterials (ENMs), with respect to their potential hazard and risk, requires an approach that makes use of the totality of available information that includes both qualitative and quantitative data as well as analysis tools. In this regard, standardized nanoinformatics data management and analysis tools are needed for the development of rationale decision tools. Accordingly, we have developed: (a) data mining and knowledge extraction approaches and tools for rapid identification of toxicity outcomes from data generated in high throughput toxicity screening (HTS) assays, (b) screening level model for estimating the environmental distribution of nanomaterials subject to various release scenarios, and (c) a decision analysis process for ranking the potential environmental impact of nanomaterials. Using HTS data predictive structure-activity relationships (SARs) for selected metal oxide ENMs were developed in order to enable environmental hazard ranking. Theses nano-SARs relate basic physicochemical properties of the ENMs to their toxicity behavior based on HTS data for various cell lines and bacteria. For the purpose of decision making and in considerations of data uncertainties, the nano-SARs were developed under different acceptance levels of false prediction of toxic outcome (i.e., false positive) or false prediction of lack of toxic outcome (i.e., false negative) resulting in a range of applicability domains for decision making. Quantitative toxicity metrics from the Nano-SARs along with estimates of exposure concentrations, obtained from a multimedia model of the environmental distribution of nanomaterials (Mend-Nano), were then combined to establish ranking of potential environmental ENM impact. Results from the above approach will be described for selected metal-oxide nanoparticles for a range of nano-SAR applicability domains and environmental scenarios demonstrating the effects of various environmental conditions on the resulting ranking of environmental impact.

M2-B.2  10:50  High-throughput screening: a transformative approach to nanotoxicology. Godwin H*, Nel A; University of California, Los Angeles

Abstract: Engineered nanomaterials (ENMs) hold tremendous promise for a wide range of applications by virtue of their highly versatile properties. While the successful implementation of nanotechnology is important for the growth of the global economy, we also need to consider the possible environmental health and safety (EHS) impact as a result of the novel physicochemical properties that could generate hazardous biological outcomes. To assess ENM hazards, reliable and reproducible screening approaches are needed to test ENMs and their base materials to determine how the physicochemical properties of ENMs correlate with biological and environmental outcomes. Within the UC CEIN, researchers have developed a range of high-throughput screening (HTS) assays that can be used to evaluate structure-activity relationships (SARs). Here, we discuss how these HTS approaches have been used to screen compositional and combinatorial ENM libraries to understand how physicochemical properties of nanomaterials correlate with specific injury mechanisms. Critically, where possible, the HTS results are validated using in vivo methodologies. This predictive approach allows the bulk of the screening analysis and high volume data generation to be carried out in vitro, following which limited, but critical, validation studies are carried out in animals or whole organisms. This approach is consistent with the recommendations of the landmark 2007 report from the US National Academy of Sciences, “Toxicity Testing in the 21st Century: A Vision and a Strategy”. Using this approach, risk reduction in the exposed human or environmental populations can then focus on limiting or avoiding exposures to ENMs that trigger these toxicological responses as well as implementing safer by design strategies to develop ENMs that are inherently safer but maintain the materials properties required for the targeted applications.

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