Assessment of Progress - Research Progress on Environmental Health and Safety Aspects of Engineered Nanomaterials - page 27

through the NPO), and little discussion of interoperability and sharing among databases. Furthermore, the
datasets are sparse, there is not a consistent level of variation in the collected data to allow rigorous
scientific synthesis, and the breadth of data and metadata needed to make the datasets useful has not been
determined or verified with a realistic “test bed” scenario.
Quantifying and Characterizing the Origins of Nanomaterial Releases
The quantities and characteristics of ENMs produced and the products that they enable influence
human and ecosystem exposures. Even a thorough understanding of ENM transport, transformation, and
effects is not sufficient to describe the effects of ENMs on human health and ecosystems if little is known
about how the materials are produced and emitted and the forms in which they are introduced into the
environment. Therefore, inventories 3 are needed that describe what ENMs are being produced, how they
are being used, and what their forms are along the value chain. However, the creation of inventories of
nanomaterials is based on the notion that there is agreement as to what constitutes a nanomaterial. The
committee returns to the issue of defining ENMs in Chapter 5.
Progress in this research priority ranged from yellow to red; no priorities were classified as green.
Yellow was the designation given for the extent of progress in developing inventories of ENMs, in
identifying critical release points along the value chain, in identifying critical populations, and in
characterizing released materials in complex environments. Because those priorities serve as a
prerequisite to model development, the ability to model releases along the value chain was denoted as red.
 Developing inventories of current and near-term production of nanomaterials
The committee identified efforts in academic and government laboratories to quantify and
characterize the origins of nanomaterial releases and private-sector efforts focused on market reports.
Production quantities, estimates of trends in production quantities, and the associated descriptions of what
is being produced are components of what is referred to as inventories of nanomaterial production. The
examples cited are not meant to be exhaustive but rather to provide evidence that progress is being made.
Work on estimating near-term inventories of nanomaterial production of many of the more commonly
cited nanomaterials (TiO2, CNTs, fullerenes, nanosilver, and nano-ZnO) at the base of the value chain
has already been published by EPA-NSF funded researchers (Robichaud et al. 2009; Hendren et al.
2011). Some of the materials were described by Michael Holman, of Lux Research, in the committee
workshop (see Appendix C) as being the most likely to dominate in commercial products in the
foreseeable future. Whether that is the case and whether more advanced (for example, hybrid 4 )
nanomaterials will grow in importance remain unclear inasmuch as estimates of nanomaterial production
are subject to constant change and the uncertainties around production quantities are large. Such
inventories are generally snapshots of nanomaterial production at a given time. The number of such
inventories is quite small, but a related consideration is the lack of a systematic process that includes
mechanisms and incentives for collecting such information; information-management plans for storage,
dissemination, and interpretation of the data; and appropriate regulatory infrastructure. Progress in
3 An inventory is a quantitative estimate of the location and amounts of nanomaterials produced or current
production capacity, including properties of the nanomaterials produced. Information on the nature of the systems
into which nanomaterials might be released during their production and the procedures for manufacturing the ENMs
are important for assessing the possible transformations that nanomaterials might undergo and the lifecycle impacts
associated with energy and material use and waste generated. A broader definition also includes an enumeration of
the amounts and uses of nanomaterials downstream in the value chain (that is, the types of products using
nanomaterials, the fraction of ENMs by weight in the products, and the quantities of these products).
4 A hybrid nanomaterial is one that results from combining different nanomaterials to form a new material that
has characteristics different from those of the original materials.