Brave New World:  Strategies for Navigating the Uncertainties
Melissa Hoffer, JD, WilmerHale, Boston, MA

Use of Nanoscale Zero-Valent Iron (NZVI) Particles for Groundwater Remediation:  A Qualitative Risk Assessment
Barbara Beck, Gradient, Cambridge, MA

Impact of Nanoparticles on Aquatic Species: Invertebrates and Fish
Patricia McClellan Green, North Carolina State University, Raleigh, NC

Inhalation Exposure to Nanoparticles
Michael Ellenbecker, University of Massachusetts, Lowell, MA

Multi-Criteria Decision Analysis and Environmental Risk Assessment for Nanomaterials
Igor Linkov, Cambridge Environmental, Cambridge, MA

A Very Brief History of Nanotechnology:  Implications for the Environment

Jeffery A. Steevens, U.S. Army Engineer Research and Development Center, Vicksburg, MS, Tel:  601-634-4199, Fax:  601-634-3120, Email:  Jeffery.A.Steevens@us.army.mil
Alan Kennedy, U.S. Army Engineer Research and Development Center, Vicksburg, MS, Tel:  601-634-3344, Fax:  601-634-3120, Emil:  Alan.J.Kennedy@us.army.mil
Charles A. Weiss, Jr., U.S. Army Engineer Research and Development Center, Vicksburg, MS, Tel:  601-634-3928, Fax:  601-634-3242, Email:  Charles.Weiss@us.army.mil
Igor Linkov, Cambridge Environmental, 58 Charles Street, Cambridge, MA 02141, Tel:  617-225-0812, Fax:  617-225-0813, Email: Linkov@CambridgeEnvironmental.com

As part of nanotechnology development, a wide variety of materials and material functionalizations are being researched.  The unique properties of these materials make this a promising area for the enhancement of military technologies and threat reduction applications.  Emerging toxicological evidence suggests these particles may pose an ecological risk and their unique properties may preclude use of existing approaches to assess their risk (exposure and effects).  We present a conceptual model, substantiated by existing knowledge and emerging research, to assess the potential ecological impacts of nanomaterials.  As part of the presentation, areas where data gaps contribute to the uncertainty in the assessment of this class of materials will be identified.  The purpose of such a conceptual model is to help direct future research to focus on relevant materials, exposure pathways, and receptors.  Ultimately the goal of such studies should be to assist the developers of this technology focus their research on materials that provide an optimal benefit to the military while minimizing the potential for adverse environmental implications.  

Brave New World:  Strategies for Navigating the Uncertainties

Melissa A. Hoffer, Esq., Wilmer Cutler Pickering Hale and Dorr LLP, 60 State Street, Boston, Massachusetts 02109, Tel: 617-526-6875, Fax: 617-526-5000, Email: melissa.hoffer@wilmerhale.com

The first half of this presentation will survey current developments in U.S. federal environmental regulation of nanomaterials, with a specific focus on the Toxic Substances Control Act.  The presentation will review other potentially applicable environmental regulatory schemes, and contrast the U.S. regulatory approach with the more precautionary approach employed by the European Union.  The presentation will review the role of voluntary standards, such as those developed by ASTM and ANSI, in environmental regulation, and discuss the relevance for stakeholders of the current voluntary standards development effort with respect to nanomaterials.  The presentation will summarize general trends emerging from research on potential health and environmental effects in connection with exposure to certain nanomaterials and highlight existing uncertainties with respect to long term implications for human health and the environment.  The second half of the presentation will identify practical approaches that currently may be employed to mitigate potential risk.

Use of Nanoscale Zero-Valent Iron (NZVI) Particles for Groundwater Remediation:  A Qualitative Risk Assessment

Barbara D. Beck, Gradient Corporation, 20 University Road, Cambridge, MA 02138, Tel: 617-395-5000, Fax: 617-395-5001, Email: bbeck@gradientcorp.com
Noelle M. Cocoros, Gradient Corporation, 20 University Road, Cambridge, MA 02138, Tel: 617-395-5000, Fax: 617-395-5001, Email: ncocoros@gradientcorp.com

We have used a risk assessment framework to evaluate use of NZVI in the remediation of groundwater trichloroethylene (TCE).  Data are not available for a formal risk assessment; however our approach should help identify approaches for evaluating risks from use of NZVI. Our aims are to: identify hazards and exposure routes potentially associated with this application; identify key data gaps and make recommendations for toxicity testing; and compare NZVI to conventional ZVI.  The potential hazards associated with this form of remediation include exposure to the ZVI nanoparticles themselves, as well as by-products of the reduction/dechlorination process.  Compared to traditional remediation of TCE, the primary benefits derived from NZVI include increased efficiency in remediation and by-products of little or no concern, although benefits are dependent on optimized remediation conditions.  Primary routes of exposure would be ingestion and dermal contact for the general community and potentially, occupational exposure via inhalation and dermal contact.  One important data gap is the limited data for the dermal and ingestion pathways compared to inhalation.  Further, very few toxicity data are available regarding NZVI specifically and it is unclear whether toxicity information from divalent and trivalent forms of iron can be extrapolated to assess toxicity of nanoparticles of zero-valent iron.  If toxicity data on Fe²⁺ or Fe³⁺ are relevant to NZVI, the natural protective mechanisms of the body against excess iron must be considered.  The multiple forms of NZVI with different physical/chemical characteristics (e.g., environmental persistence) should be considered with respect to toxicity.  Efforts being made in the field to reduce agglomeration of NZVI particles should consider potential increases in hazard.  Overall, based on the lack of hazardous by-products, the increased remediation efficiency, and the tendency of the particles to agglomerate, therefore likely reducing uptake, the risks of NZVI appear to be low with a positive risk-benefit ratio, but important data gaps remain.

Impact of Nanoparticles on Aquatic Species: Invertebrates and Fish

Patricia McClellan-Green, Department of Environment and Molecular Toxicology and Center for Marine Sciences and Technology, North Carolina State University, 303 College Circle, Morehead City, NC 28557, Tel:  252-222-6367, Fax:  252-222-6311

Nanomaterials have recently experienced an exponential growth in their production and usage.  Applications of these materials are dramatically expanding because of their small size and their unique physical and chemical properties.  Nanomaterials are currently used in cosmetics, as environmental remediation agents, employed in various pharmaceutical formulations, for the development of semi-conductors, electronics, and in the development of alternative energy sources.  Recently, studies have shown that many nanomaterials possess cytotoxic properties in both in vitro and in vivo systems.  While many of these materials do not appear to be acutely toxic, organisms exposed to nanomaterials, e.g. fullerenes, do experience increased levels of lipid peroxidation and altered mitochondrial and enzymatic protein levels and activities.  The goal of this study was to examine the behavior of fullerenes in the marine environment and determine the impact of exposure on pelagic and benthic organisms.  Two invertebrate species as well as the benthic estuarine teleost Fundulus heteroclitus were exposed to increasing concentrations of fullerenes for 96 hours.  Their uptake levels were monitored and the levels of antioxidant enzyme activities measured.  No acute toxicity was observed in either species up to 20 ppm nC60.  Uptake of fullerenes in the invertebrates was similar to that previously observed for daphnia (Oberdorster et al., 2006).  The levels of antioxidant enzyme activities are currently being analyzed.  In a companion study, it was determined that the extraction techniques of Oberdörster (2004) were not adequate to detect fullerenes in seawater.  C60 in combination with certain oxidizers, such as magnesium perchlorate, caused materials to “salt out” as the overall salinity of the aqueous media increased.  Additional studies were conducted comparing the type and concentration of oxidizing agents, including magnesium perchlorate, sodium hypochlorite (bleach), and hydrogen peroxide, in order to achieve maximum fullerene recovery from waters with varying salinities.

Inhalation Exposure to Nanoparticles

Michael J. Ellenbecker, University of Massachusetts Lowell, One University Avenue, Lowell, MA, 01854, Tel: 978-934-3272, FAX: 978.934.3050, Email: ellenbec@turi.org.

Workers and the general public may be exposed to airborne nanoparticles during the manufacture of the nanoparticles, their incorporation into nano-devices, the use of the devices, and in the end-of-life disposal of those devices.  At this time, little is known about the potential for inhalation exposure to nanoparticles during each phase of their life cycle.  In addition, very little is known about effective methods to control such airborne exposures. 

These issues are the subject of ongoing research at the NSF-funded Center for High Rate Nanomanufacturing (CHN) located at the University of Massachusetts Lowell, Northeastern University, and the University of New Hampshire.  The primary mission of CHN is to develop manufacturing processes that move nanomaterials and devices from the laboratory to the production phase.  A unique element of this Center is the complete integration of occupational and environmental health and safety into its mission.  CHN is committed to developing and using nanomaterials and nanomanufacturing methods that are environmentally beneficial and healthful for workers.  As part of this work, we are characterizing worker exposure to nanomaterials being used in the CHN laboratories.  For example, several laboratories are using carbon nanotubes (CNTs) and fullerenes in innovative applications.  We are measuring both nanoparticle air concentrations and detailed size distributions, which will be used together with lung deposition models to predict regional lung deposition.  We are also developing control strategies for all exposures to nanoparticles and other exposures deemed to be hazardous.  For nanoparticles this may well include the development of novel ventilation and filtration systems, as well as improved personal protective equipment. 

This paper will present the current state of knowledge concerning the hazards from inhalation of nanoparticles and effective methods to control such exposures.  It will also recommend needed research initiatives to increase our understanding of nanoparticle inhalation.

Multi-Criteria Decision Analysis and Environmental Risk Assessment for Nanomaterials

Igor Linkov, Intertox Inc., 83 Winchester Street, Suite 1, Brookline, MA 02446, Tel: 617-233-9869, Email: ilinkov@intertox.com
F. Kyle Satterstrom, Cambridge Environmental Inc., 58 Charles Street, Cambridge, MA 02141
Jeffery Steevens, Elizabeth Ferguson, Jongbum Kim, and Burton Suedel, US Army Corps of Engineers, Engineer Research & Development Center, 3909 Halls Ferry Road, Vicksburg, MS 39180

Even though nanotechnology application is widespread, understanding of the environmental effects and risks associated with nanomaterial use is very limited and often contradictory.  Although it was originally thought that these materials were biologically benign, recent studies have suggested that inhalation and dermal absorption of these materials may have deleterious effects on mammals and a potential for adverse ecological effects.  Nanoparticle production processes and nanomaterial uses in consumer products may result in exposures and risks. Regulatory experience with inorganic and organic chemicals may not be directly relevant to nanomaterials since their physical and biological properties are often determined not only by their size or structure, but rather by functionalization that was engineered to achieve specific manufacturing goals.  Even though the risk assessment paradigm successfully used by EPA since the early 1980s may be generally applicable to nanomaterial regulation, its application requires incorporating an uncertainty in basic knowledge that is much larger than the uncertainty for other materials.  An additional challenge is balancing environmental and societal goods and risks associated with nanomaterials.  This paper proposes a risk assessment and risk management framework utilizing multi-criteria decision analysis (MCDA) and adaptive management for nanomaterial regulation.  Given the uncertainty in all aspects related to nanomaterials, the structured, transparent, and justifiable tools offered by MCDA for quantifying both scientific and decision-makers’ values and views, as well as for developing a system of performance metrics consistent with regulatory requirements, may be especially valuable for this emerging field.  The development and implementation of such a framework will make clear what information should be collected to support decisions.  MCDA tools, coupled with value of information analysis and adaptive management, could provide a good foundation for both bringing together multiple information sources to assess risks associated with nanomaterials and also for developing justifiable and transparent regulatory decisions. 

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