(141a) Multimedia Environmental Distribution of Nanomaterials

Nanotechnology has brought about many benefits and improvements to commercial and industrial applications, but its potential risks to the environment must also be systematically assessed. In this regard, exposure levels (i.e. concentrations, exposure time, etc.) of engineered nanomaterials (eNMs) in the environment are crucial to assessing and managing risks due to potential release of eNMs to the environment. Although models are available for predicting the multimedia environmental distribution of organics chemical contaminants, such models cannot be directly applied to eNMs due to the differences in the fate and transport (F&T) behavior of eNMs. Although “substance flow analysis” estimations have been employed in recent years as part of life cycle analysis (LCA), such analyses are not a priori predictive and do not consider mechanistic descriptions of fundamental transport processes. Accordingly, in the present study, a generalized model of the multimedia environmental distribution of engineered nanomaterial (Mend-Nano) is developed via multimedia fate and transport model to estimate the potential exposure levels to ENMs. The multimedia environment is considered as a collection of environmental compartments and subcompartments, with each compartment treated as either well-mixed (e.g. atmosphere, water), or non-uniform compartments (e.g. soil, sediment) that uses convection-diffusion models to increase spatial resolution. Fundamental intermedia transport processes (e.g. dry deposition, rain scavenging, resuspension, runoff) are then used to link various compartments while considering the particle size distribution (PSD) of eNMs in both the atmospheric and aquatic compartments. In order to enable rapid “what-if?” scenario analyses, a web-based graphical user interface (GUI) was developed for the model as part of a cloud-based modeling system. In the present model, the user defines the modeling scenario via the web-based GUI by specifying relevant properties of the eNM under consideration, geographical and meteorological parameters (i.e., size of regions, temperature, wind speed, rain rates, etc.), transport process parameters and source emission estimates (i.e., release rates, etc.). The model then calculates the dynamic change of ENM concentration and mass in each environmental compartments, and displays the result within the GUI. It is envisioned that the present multimedia analysis tool will assist regulators, industrial, and academic users in rapidly assessing the potential environmental implications of ENMs releases to the environment.