R1 AM Nanotechnology Environmental and Health Impacts|
Thursday, 17 November 2005: 8:00 AM - 11:40 AM in Ballroom 1
601 (HAN-1117-791093) State-of-the-art Critical Review of the Potential Hazards of Manufactured Nanomaterials.
Start time: 8:00 AM
Hansen, S1, Krayer von Krauss, M1, Baun, A1, 1 Center of Environmental Assessment of Nanotechnology, Institute of Environment & Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
"When the very small becomes very big" is often how NanoScience and Technology (NST) is described - big opportunities, big business and big potential impacts on our future. Until recently the potential negative impacts of NST on human health and the environment were rather speculative and unsubstantiated. However, within the past years, a number of studies have indicated that exposure to free nanoparticles can be cytotoxic and adverse effects have been documented in test animals such as rats and fish. In addition, a number of characteristics of nanoparticles such as size, persistency and mobility make it possible to draw specific parallels to past negative experiences with xenobiotic organic chemicals, asbestos, methylmercury and tetraethyl lead. Since the SETAC-meeting in Portland, OR which addressed some of these issues on NST, several studies have been published and more are underway. This presentation provides a critical review of the state-of-the-art concerning the proclaimed health hazards and environmental effects of manufactured nanoparticles related to potential risks of exposures to nanoparticles. The review was compiled after detailed literature searches and cross referencing and scrutiny of relevant websites concerning NST. The identified potential hazardous effects are shortly described and the empirical findings are summarized. Potential future impacts are discussed in view of the fact that humans and the environment are already being exposed to manufactured nanoparticles through cosmetics, textiles, paints and electronics. The nature of these risks may be as novel as the technology itself, and past methods for risk assessment might not apply. In this presentation, main areas of uncertainty and research needs are identified.
602 (GRA-1117-828928) Impacts of Manufactured Nanomaterials on Human Health and the Environment: A Focus on Nanoparticulate Aerosol.
Start time: 8:20 AM
Grassian, V1, O'Shaughnessy, P1, Thorne, P1, Dodd, A1, Knagge, K1, Pettibone, J1, 1 University of Iowa
The goal of this research is to determine the potential effects of manufactured nanomaterial aerosol on human health. Manufactured nanomaterials are characterized using a wide variety of techniques and analysis methods including surface spectroscopy so that both bulk and surfaces properties can be understood on a molecular level. Because of a number of physical and chemical properties are size-dependent on nanometer length scales, it is important to fully characterize the nanoparticles used in these studies. These well-characterized particles are then used for inhalation exposure studies. There is additional characterization once the aerosol is generated to determine if the particles aggregate or retain the size distribution determined prior to aerosol generation. Toxicology assessments of the animals used in the exposure studies include murine acute pulmonary inflammation assay, murine sub-acute pulmonary toxicology evaluation and murine microbial challenge host resistance evaluation to screen for acute and sub-chronic pulmonary effects. Data obtained for particles as small as 5 nm (titanium dioxide) will be discussed and compared to larger particles.
604 (CUN-1117-661727) Assessing the Safety of Nanoscale Materials using a Systems Biology Approach.
Start time: 9:00 AM
Cunningham, MJ1, Magnuson, SR2, Falduto, MT 2, Balzano, L3, Resasco, DE3, 1 Houston Advanced Research Center, The Woodlands, TX, USA2 GenUs BioSystems, Inc., St. Charles, IL, USA3 University of Oklahoma, Norman, OK, USA
Nanomaterials vary greatly in their composition and preliminary reports are mixed as to their toxicity. In this study, single-walled carbon nanotubes (SWNT) were manufactured using a modified chemical vapor deposition method (CoMoCAT) developed at the University of Oklahoma. SWNT were purified in hydrofluoric acid and characterized to have average lengths of approximately 100 nm and average diameters of 3 nm. The percentage of heavy metal impurities were less than 1%. Their safety was assessed by exposing primary neonatal human epidermal keratinocytes in vitro at 0.001 mg/mL (noncytotoxic) and 1 mg/mL (cytotoxic). Cells were harvested at 8 different time points within a 24 hour period for each dose curve. The same experimental design was used in studies of untreated cells (control) and known control compounds, such as silica (Min-U-Sil®5, SiO2), carbon black (Printex®90, CB) and carbonyl iron (ferronyl iron, FI). Cell pellets were snap-frozen for subsequent total RNA isolation. Biotinylated cRNA probes were synthesized from the isolated RNA and hybridized onto CodeLink™ microarrays containing oligomers from 9,970 unique human genes. Initial data analysis analyzed by hierarchical agglomerative clustering (Euclidean distance metric, average linkage) showed that at the nontoxic dose, the profile for SWNT was more similar to the nontoxic FI than to the toxic SiO2. In evaluating the high dose, the profile for SWNT was more similar to SiO2 than to FI. Additional analysis involved supervised mathematical modeling methods as well as pathway analysis for up- and down-regulated genes. In most profiles, structural proteins, such as laminin, and several cytokines were significantly expressed, as had been previously reported. Two possible biomarkers for SWNT exposure are kallikrein and NICE. Min-U-Sil and Printex90 are registered trademarks of U.S. Silica Company and Degussa Corporation, respectively, and CodeLink is the trademark of GE Healthcare.
Start time: 9:20 AM
605 (BRA-1117-723656) Addressing the uptake of nanoaluminum particles by rye grass and bean plants.
Start time: 10:00 AM
Doshi, Reeti1, Braida, Washington1, Christodoulatos, Christos1, O'Connor, Gregory2, 1 Stevens Institute of Technology-CES, Hoboken, NJ, USA2 US Army, Environmental Technology Division, Picatinny Arsenal, NJ, USA
The development of nanotechnology and the manufacture of new organic and inorganic nanosized materials will very likely result in the release of substantial amounts of these materials into the environment. The fate and transport of nanosized materials, once they are released into the environment, has not yet been fully addressed, nor have the impacts of those materials on plants and soil communities. Nanoaluminum is being used in increasing quantities as energetic material. As part of an ongoing research effort, the effects of two types of nanosized aluminum particles on the growth of rye grass and California red kidney bean plants and their uptake have been studied. The soil used was fully characterized (total heavy metals content, texture, TOC, nitrogen, TCLP, pH). The aluminum particles are 100 nm in size and they are coated with a thin layer of aluminum oxide or an organic carboxylic ligand. The Al concentration in the soil ranged from 10 to 10,000 mg/kg of soil. Polymer micro samplers have been used to obtain water samples for evaluation of the dissolved aluminum concentration during the growth of the plants. Soil pH was also monitored along with visual observations of the plants during growth. At the end of the experiment, plants were harvested and the total amount of aluminum taken up by the plants and translocated was determined by ICP- OES after microwave acid digestion. The effects of plant growth on nano Al dissolution were assessed. Correlations between the Al taken up by the plants and the total and dissolved amount of Al in the replicate were developed.
606 (HOL-1117-827884) Transformations of Biologically-Conjugated CdSe Quantum Dots Released into Water and Biofilms.
Start time: 10:20 AM
Holden, P1, Nadeau, J2, Stoimenov, P1, Priester, J1, 1 University of California, Santa Barbara, CA, USA2 McGill University, Montreal, Quebec, Canada
Semiconductor nanocrystals (quantum dots) differ in important ways from bulk semiconductor materials. Their increased band gap means that they function as strong oxidizing and/or reducing agents, and their small size allows them to pass into living cells. Conjugation of biomolecules to the crystal surface can alter any or all of these properties. We previously observed that nucleobase-conjugated CdSe quantum dots were actively taken up by soil and water bacteria (for example, Bacillus subtilis and Escherichia coli). Effects on microbial viability attributed to the presence of the quantum dots included slower doubling times, heavy metal sequestration, and blebbing of metals into the environment. The work here is towards quantifying such effects using a variety of biologically-conjugated quantum dots and an assortment of microbial species, monitoring the process of quantum dot uptake and breakdown and characterizing the breakdown products that result from bacterial metabolism of these particles. Comparisons are made to constitutent dissolved metals to infer toxicity proceses specific to nanoparticles. Liquid culture and unsaturated biofilm format are used for studying a realistic environmental array of bacteria with initial focus on Pseudomonas aeruginosa, an opportuntistic pathogen that is also important in nutrient cycling. Consequences of toxicity to microbial populations through contamination of soil and water with quantum dot breakdown products are projected.
607 (TEM-1117-550779) Lifecycle Effects of Bulk and Purified Carbon Nanotubes on an Estuarine Meiobenthic Copepod.
Start time: 10:40 AM
Templeton, R1, Ferguson, P1, Chandler, G1, 1 University of South Carolina
Two full life-cycle bioassays were performed using Amphiascus tenuiremis (ASTM method E-2317-04) to test the toxicity of Single Walled Carbon Nanotubes (SWCNTs). A cohort of <24hr old nauplii were tested by culturing single nauplii in individual 96-well microplate wells (n=35 nauplii/plate/treatment, 3 replicates/treatment) amended with SWCNTs in seawater. 10ppm, 1.62ppm, 972ppb, 583ppb, and 0ppb of non-purified and electrophoretically purified carbon nanotubes in 30ppt seawater were assayed. On day 20 of each bioassay, surviving adult male and female copepods were mated, pairwise. Purified/dialyzed SCWNTs showed very little toxicity in all treatments, with no significant differences in survival rates, mating success, or the number of viable offspring per mating pair across treatments (=0.05). Development was not significantly affected from the naupliar to copepodite stages nor from naupliar to adult male or female; however a significant 10% enhancement in development rate from copepodite to the adult female stage was seen in the 583ppb treatment when compared to controls (p=0.04). In contrast, bulk/dialyzed SWCNTs (containing smaller carbon nanomaterial impurities) exhibited sharply increased toxic effects with increased concentration. Relative to controls, survival rates were significantly decreased by 64% and 20% to the copepodite stage, and 80% and 20% to the adult stage for the 10ppm and 1.62ppm treatments, respectively (p<0.05). Naupliar development to the copepodite stage at 10ppm was delayed significantly by 56% compared to the control (p<0.0001). Copepodite to adult stage development was not delayed for female or male copepods at 10ppm; however significant delays of 24% for females (p=0.03) and 22% for males (p=0.03) were seen for naupliar growth to adult stages at 10ppm. These results suggest size-dependent toxicity for SWCNT based nanomaterials, with the shortest, least commercially-utilized, waste fractions resulting in increased mortality and delayed larval development. Purified SWCNTs appear non-toxic up to the environmentally unlikely 10ppm concentration.
608 (LOV-1117-732015) The Influence of Nanoparticles on Behavior: The Diminutive Diet of Daphnia.
Start time: 11:00 AM
Lovern, S1, Klaper, R1, Strickler, J1, 1 University of Wisconsin-Milwaukee Great Lakes WATER Institute, Milwaukee, WI, USA
As technology advances from using fine to nanoscale particles, the chemical and physical properties of these particles change as well as an increased surface area to volume ratio. With these changes, organisms can be greatly affected. This is especially true of aquatic organisms filtering their environment for food. In our previous work, we have found titanium dioxide (TiO2) and fullerenes (C60) to negatively influence survival of the Cladoceran Daphnia magna. In our current work, we are examining the behavior of Daphnia in response to nanoparticles. Other research with Daphnia has shown size and charge to be a factor in particle uptake; however, previous researchers did not examine particles at the nanoscale. During survival experiments at sublethal concentrations of nanoparticles, we found changes in behavior which are considered abnormal. Daphnia were often immobilized and appeared to be unable to swim down from the surface. The Daphnia would also swim in small circles or collide with vessel walls. In an effort to quantify these behavioral alterations, we have recorded Daphnia using a high-speed camera attached to a microscope mounted at 90°. A Picospritzer II (General Valve Corp) was used to expose tethered Daphnia to control as well as nanoparticle suspensions. Behavioral responses were recorded and specific behavior modifications will be shown in video clips. As changes in zooplankton behavior are known to affect predation risk, understanding the alternations caused by nanoparticles will help evaluate the sublethal effect of nanoparticles on the aquatic environment.
609 (RIN-1117-833304) Characterization of nanoparticle risks in aquatic organisms.
Start time: 11:20 AM
Ringwood, A1, Gonsalves, K2, Khambhammettu, S2, 1 Deparment of Biology, UNC-Charlotte, Charlotte, NC, USA2 Department of Chemistry, UNC-Charlotte, Charlotte, NC, USA
There are numerous potential environmental risks of engineered nanoparticles that are not yet well-characterized or understood. Nanoparticles may be introduced into aquatic environments during production processes and also as a result of release following their use in electronic and biological applications. The purpose of these studies was to characterize the behavior of quantum dots (QD) in seawater, and the accumulation of and toxicity to potential biological receptors. There are natural differences in environmental factors that may affect the degradation rates of QDs, including salinity and pH conditions, as well as seasonal differences in temperature. To determine the effects of salinity on degradation rates, nonfunctionalized QDs composed of a Cd/Se core surrounded by layers of Zn (Evident Technologies) were added to 0.22 filtered seawater samples of different salinities (10, 20, and 30 parts per thousand), and the changes in emission spectra over time were determined; likewise, the potential effects of pH were evaluated under a range of environmentally realistic pH conditions (e.g. pH 7, 7.5, and 8); and the impacts of temperature (10, 20, and 30 degrees centigrade) were determined. The accumulation and potential toxicity of QDs was evaluated using oysters, Crassostrea virginica. For these studies, oyster embryos as well as isolated hepatopancreatic cells were used. Fluorescent confocal microscopy and electron microscopy were used to verify the accumulation and cellular localization. Toxicity to embryos was evaluated using the bivalve embryo development assay, and toxicity to hepatopancreatic cells was determined using the lysosomal destabilization assay. These kinds of basic studies are essential for addressing the potential impacts of nanoengineered particles on aquatic organisms.