Development of an Integrative Framework to Assess the Environmental Impacts of Engineered Nanomaterials
The overarching goal of this work is to develop a framework and tools for assessing the environmental and human health impacts of Engineered Nanomaterials (ENMs). As a first step, the analysis focused on the identification of the types of decision makers that need to be able to assess the environmental impacts of ENMs and the contexts in which they are making decisions (decision scenarios). Next, a literature review was conducted to determine the utility of existing environmental impact assessment frameworks for these different decision scenarios, and to analyze which of these existing frameworks are most useful for assessing the potential impacts of ENMs in each decision-making context and what gaps exist. This analysis revealed that there is a significant need for a practical tool that decision makers can use to assess whether they have sufficient data available to conduct an environmental impact assessment for a specific group of ENMs for a specific decision context. To address this gap, the core of this thesis presents the development of a decision-support tool that employs an evidential reasoning algorithm to assess data required for environmental impact assessment of ENMs. As a proof of concept, this approach was employed to evaluate whether sufficient data are available to assess the environmental impact of nano Copper and nano Copper Oxide, nano Zinc Oxide and nano Titanium Dioxide (nano Cu-CuO, nano ZnO and nanoTiO2) in four different risk scenarios. This analysis revealed that sufficient data are available to assess the risk potential of TiO2 in consumer products and occupational settings and that sufficient data are available to assess the risk potential of nano Cu-CuO with respect to aquatic environments. In all of the other combinations of materials and scenarios explored, the results show that additional data on the environmental fate and transport and regarding exposure potential are needed to be able to assess potential environmental impact. The final section of this thesis focuses on the implications that this and other work in the field of Environmental Health and Safety for Nanomaterials (Nano EH&S) have for our overall understanding of the risk of ENMs to human health. Specifically, key questions of concern to the public health community are proposed, and answers to these questions and remaining gaps are provided based on a comprehensive review of major accomplishments in the field of Nano EH&S over the last decade and a half. An overarching set of conclusions is provided in chapter five summarizing the scientific contributions of this work. The chapters of this work constitute important progress towards the development of frameworks and tools for characterizing the environmental and human health impacts of ENMs.