Research-Engineering Research Accelerator - Carnegie Mellon University

NEEP Research

The NEEP IGERT research plan supports the educational activities to produce an environmentally and policy-literate generation of nanoscience professionals. The highly interdisciplinary research addresses critical uncertainties surrounding the effects of manufactured nanomaterials/nanoparticles (NPs) on ecosystems, their movements through the environment, their interactions with organisms, the mechanisms by which they exert their influence, and thus, their potential environmental impacts. Coupled to this is the consideration of the societal context of ethics, risk analysis and regulatory policy.

A distinctive element of our IGERT is the synthesis of fundamental fate, transport, and effects information for nanomaterials/NPs into a rigorous risk assessment framework. (Figure 1) The students and their mentors construct risk assessments that characterize the range, location, and medium of environmental discharges of the nanomaterial, based on scenarios of use, while considering matrix and coatings, storage, wear, transformations (“aging”), and end of life scenarios. Nanoparticle-specific models of persistence, transport, and accumulation due to physical or biological processes, will be developed, which will enable the estimation of ambient concentrations and exposures for the relevant end points at the individual, population, or ecosystem function levels.

Fig. 1. A general risk analysis framework for nanomaterials. At present, for nanomaterials, there are scientific gaps in each of the categories, making quantitative risk estimation difficult. The research of the IGERT students will fill the critical knowledge gaps and evaluate the adequacy of this framing and develop alternatives, as appropriate.

Nanomaterials are products containing NPs in matrices. Released NPs do not move in the environment the same way as conventional pollutants. They tend to accumulate it interfaces rather than mixing homogeneously; they tend to aggregate, and the aggregation can affect their biological properties; matrix effects and organic coatings can change their chemical attributes. IGERT students will adapt current risk models to properly account for these considerations, a truly interdisciplinary challenge achievable through the combined efforts of students across disciplines. Essential to these endeavors are 1) determining the sources and forms of engineered NPs entering the environment and distinguishing natural and incidental NPs from manufactured ones; 2) understanding the nature and rate of biotic and abiotic transformations (aging) of NPs occurring in the environment; 3) determining the propensity of NPs to attach to inorganic and organic environmental surfaces; 4) identifying the modes of toxicity of NPs, elucidating the “nano” effect beside the high surface-to-volume ratio, and identifying methods to avoid toxicity; and 5) reducing the complexity of nanomaterial risk assessment in order to make science-based policy decisions regarding the use and safety of nanomaterials.

"Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation."