The Ecological Effects of Nanomaterials: Are New Stressors Associated with New Technologies?

L.Ziccardi, M. McArdle, Y. Lowney, J. Tsuji

The U.S. Environmental Protection Agency (EPA) defines nanotechnology as “research and technology development at the atomic, molecular, or macromolecular levels using a length scale of approximately one to one hundred nanometers in any dimension.” Nanomaterials include naturally-occurring particles, those that are produced from combustion byproducts, and engineered or manufactured nanomaterials. Nanoparticles can be released to the environment from deliberate application (e.g., remedial applications), and from unintentional or incidental releases, where they could come into contact with fish, wildlife, and plants. These organisms, termed “ecological receptors,” can potentially be exposed to nanoparticles through inhalation, ingestion, movement across gills, passive transport, and cellular absorption.

The unique physicochemical properties of nanomaterials that make them beneficial in commercial applications might also result in unexpected biological interactions. For example, their large surface area relative to mass may translate to enhanced chemical binding capacity and reactivity. Another consideration in aquatic environments is that smaller particles will remain in suspension longer, which may affect their environmental transport, bioavailability, and toxicity. On the other hand, nanoparticles’ high surface area and associated intermolecular forces may increase agglomeration and adherence to suspended matter or sediments, potentially reducing bioaccessibility.

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Decision Support Tools for Environmental Remediation and Restoration

Making decisions involves making trade-offs. If a course of action is obvious, that doesn’t really require making a decision. Companies may face complex environmental decisions such as, “Should we remove all soils and sediments above 1 ppm and dig up forested wetland habitat areas in the process? What about restoration options? Should we spend $500,000 restoring non-contiguous areas of predominantly Phragmites, or is that money better spent enhancing existing contiguous habitat areas?”

Every decision has an overall objective. For example, a company may wish to maximize environmental benefits while minimizing cost, or more specifically, restore and augment a migratory flyway at lowest cost. Lowest cost does not mean choosing the least favorable option or shirking responsibility. It means allocating limited resources most efficiently. There is almost always uncertainty about the data (and/or models) that support a decision. “What is the range of risks at our site? What are the consequences of making a wrong decision (e.g., reality is not at the expected value)?” If consequences are high, the importance of the decision is high, too.

There are tools and analytical methods that can help sort out such complexities. Net environmental benefits analysis, relative risk models, and a host of multi-criteria decision analysis tools are all available to help evaluate multiple alternatives against a consistent set of criteria. These tools are designed to integrate different kinds of information, analysis, and data that all contribute to the decision-making process, including, for example, stakeholder acceptance, cost, risk, and impacts on habitat. Such tools make the decision process more transparent, by providing an analytical framework for integrating disparate results. How do you directly compare human health and ecological risk, impact on habitat, and cost across competing alternatives when these all differ?

In the next newsletter, we will present some ideas, including case studies, on this topic.

New Faces

Ken Cerreto
Freshwater Ecologist, EcoSciences
Maynard, MA

Mr. Cerreto specializes in ecological risk assessment and field sampling. He has a wealth of field sampling experience in aquatic and terrestrial systems, has managed field sampling programs, and is skilled at sampling both environmental media and biota. Prior to joining Exponent, Mr. Cerreto was an Aquatic Ecologist at ENSR, an Ecologist at AMEC Earth & Environmental, and a Research Assistant at the University of Wyoming, Laramie. He was also an Assistant Scientist at Menzie-Cura & Associates, Inc, where he worked with a number of his present colleagues at Exponent. He holds master’s degrees in Zoology and Physiology from the University of Wyoming and a bachelor’s degree in Biology and Pre-med from College of the Holy Cross.

Brianne Duncan
Scientist, Environmental Sciences
Bellevue, WA

Ms. Duncan's background is in biology and chemistry; she holds a B.S. in biology with a minor in chemistry from Seattle University.

Dr. Ann Michelle Morrison
Aquatic Ecotoxicologist, Environmental Sciences
Maynard, MA

Dr. Morrison has a strong interest in data analysis, specifically in applying statistical methods from other fields (e.g., medical) to environmental data. Prior to joining Exponent, Dr. Morrison worked in the Benthic Ecology Research Program in Bermuda assisting in the assessment of Bermuda’s near shore environment by assessing the health of seagrass beds, coral reefs, and mangrove swamps. She holds an Sc.D. in Environmental Health from Harvard University, an M.S. in Environmental Health from Harvard University, and a B.S. in Biology from Rhodes College.

Dr. Karen Murray
Senior Scientist, Environmental Sciences
Maynard, MA

Dr. Murray studies the role of bacteria in the environmental transport and fate of metals. She has experience in field sampling in marine, freshwater, and soil systems. Her analytical expertise includes aerobic and anaerobic microbial culturing techniques, electrochemical and spectroscopic chemical analyses, and molecular biological methods. Dr. Murray holds a Ph.D. in Oceanography (Geochemistry) from the Scripps Institution of Oceanography, University of California, and a B.S. in Environmental Engineering Science from the Massachusetts Institute of Technology.

Dr. Katherine (Johnson) Palmquist
Senior Scientist, EcoSciences
Bellevue, WA

Dr. Palmquist has a strong interdisciplinary background in insect biology/physiology, toxicology, integrated pest management, and communications. She has developed and published methodology concerning the laboratory maintenance and rearing of several stream insect species. Additionally, she has experience in performing lotic and lentic benthic surveys, as well as terrestrial insect field sampling. She holds a Ph.D. in Toxicology from Oregon State University, and a B.S. in Entomology from Washington State University.

Ramón Pierce
GIS Analyst, EcoSciences
Bellevue, WA

Mr. Pierce specializes in the functionality of the ESRI ArcGIS suite software and its extensions, including spatial analysis (e.g., short-path analysis, calculating the slope of an elevation, contour interpretation, reclassifying and creating cost data sets and weighting) and 3-D analysis (e.g., creating surface models, interpolating raster surfaces, and creating features from surfaces). Mr. Pierce’s previous experience is in traffic information. He holds a B.A. in Urban Studies from the University of Washington, and a Certificate in Geographic Information Systems and Spatial Modeling from the University of Washington.

Dr. David J. Rowan
Senior Scientist, EcoSciences
Boulder, CO

Dr. Rowan has more than 15 years of experience in environmental consulting and research. He has expertise in food web, bioenergetics, and transport and fate modeling of radionuclides, metals, and organics. Dr. Rowan has served on advisory boards for IAEA, NCRP, and EPRI and has managed many projects, both large and small, for government and industry. He holds a Ph.D. in Biology from McGill University, and an M.S. and B.S. in Geology, both from The Ohio State University.

Recent/Upcoming Publications

Bessinger, B.A., Redding, B., and Y.W. Lowney. 2007. Comments on “Release of Arsenic to the Environment from CCA-Treated Wood. 2. Leaching and Speciation during Disposal.” Environ. Sci. Technol. 41 (1):345–346.

Bigham, G., W. Chan, M. Dekermenjian, and A. Reza. Accepted. Indoor concentrations of mercury vapor following various spill scenarios. Environ. Foren.

Booth, P., N. Gard, S. Law, and R. Davis. 2007. Sustainability: Considerations for including eco-assets in a company’s bottom line. ABA Section of Environment, Energy, and Resources’ Climate Change, Sustainable Development, and Ecosystems Committee Newsletter 11(1):7–11.

Chan, W.R., W. Nazaroff, P. Price, and A. Gadgil. 2007. Effectiveness of urban shelter-inplace– II: Residential districts. Atmos. Environ. 41:7082–7095.

Goldstone, J.V., H.M.H. Goldstone, A.M. Morrison, A.M. Tarrant, S.E. Kern, B.R. Woodin, and J.J. Stegeman. In press. Cytochrome P450 1 genes in early deuterostomes (tunicates and sea urchins) and vertebrates (chicken and frog): Origin and diversification of the CYP1 gene family. Molec. Biol. Evol. MBE Advance Access published online October 4, 2007.

Johnson, M., M. Korcz, K. von Stackelberg, and B. Hope. In preparation. Spatial analytical techniques for risk based decision support systems. In: Decision Support Systems for Risk Based Management of Contaminated Sites. To be published by Springer Verlag.

Kay, D.P., J.L. Newsted, M.T. BenKinney, T.J. Iannuzzi, and J.P. Giesy. (In press). Passaic River sediment interstitial water Phase I toxicity identification evaluation. Chemosphere.

Menzie, C., P. Booth, S. Law, and K. von Stackelberg. In preparation. Defining the problem. In: DSSs for Inland and Coastal Waters Management section, Decision Support Systems for Risk Based Management of Contaminated Sites. To be published by Springer Verlag.

Murray, K.J., and B.M. Tebo. 2007. Cr(III) is indirectly oxidized by the Mn(II)-oxidizing bacterium Bacillus sp. strain SG-1. Environ. Sci. Technol. 41:528–533.

Murray, K.J., S.M. Webb, J.R. Bargar, and B.M. Tebo. 2007. Indirect oxidation of Co(II) in the presence of the marine Mn(II)- oxidizing bacterium Bacillus sp. strain SG-1. Appl. Environ. Microbiol. 73(21):6905–6909.

O’Reilly, K. 2007. Science, policy, and politics: The impact of the information quality act on risk-based regulatory activity at the EPA. Buffalo Environ. Law J. 14(2):249–288.

Shock, S.S., B.A. Bessinger, Y.W. Lowney, and J.L. Clark. 2007. Assessment of the solubility and bioaccessibility of barium and aluminum in soils affected by mine dust deposition. Environ. Sci. Technol. 41 (13):4813–4820.

von Stackelberg, K., M. Nelson, B. Southworth, J. Cura, and T. Bridges. In press. Evaluation of sources of uncertainty in a subset of risk assessments conducted for the U.S. Army. Integ. Assess. Environ. Manage.

Recent/Upcoming Conferences & Presentations

IEEE Symposium on Product Compliance Engineering
Longmont, CO
October 22–23, 2007
The influence of regulatory changes on unique product designs.
BenKinney, M., A. Arora, and J. Swart.

23rd Annual International Conference on Soils, Sediments, and Water
University of Massachusetts at Amherst
October 15–18, 2007
Identification of natural gas sources using geochemical forensic tools.
Boehm, P., T. Saba, and L. Benton.

North Atlantic Chapter of Society of Environmental Toxicology and Chemistry
Bristol, RI
June 13–15, 2007
Experience in applying the weight-of-evidence approach to aquatic sites contaminated with heavy metals.
McArdle, M.E., C.A. Menzie, and S. Kane-Driscoll.

Methyl Bromide Alternatives Conference
San Diego, CA
October 29–November 1, 2007
Modeling and measurement of methyl bromide at food processing facilities.
Winegar, E., R. Reiss, and W.R. Chan.

International Symposium on Nanotechnology in Environmental Protection and Pollution
Fort Lauderdale, FL
December 11–13 2007
The ecological effects of nanomaterials: Are new stressors associated with new technologies?
Ziccardi, L., M. McArdle, and Y. Lowney.