2009 Progress Report: Aquatic Toxicity of Carbon-Based Nanomaterials at Sediment-Water InterfacesEPA Grant Number: R833316
Title: Aquatic Toxicity of Carbon-Based Nanomaterials at Sediment-Water Interfaces
Investigators: Deng, Baolin , Ingersoll, Chris , Li, Hao , Wang, Ning
Institution: University of Missouri - Columbia
EPA Project Officer: Hahn, Intaek
Project Period: April 1, 2007 through June 30, 2010
Project Period Covered by this Report: April 1, 2009 through March 31,2010
Project Amount: $399,506
RFA: Exploratory Research: Nanotechnology Research Grants Investigating Environmental and Human Health Effects of Manufactured Nanomaterials: a Joint Research Solicitation-EPA, NSF, NIOSH, NIEHS (2006) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , Health Effects , Nanotechnology , Health , Safer Chemicals
This study aims to investigate toxicity of carbon-based one-dimensional nanomaterials toward aquatic organisms that inhabit sediment-water interfaces and to identify factors controlling the toxicity to sediment-dwelling organisms. Carbon nanotubes (CNTs) often contain heavy metals which are mostly introduced as catalysts for their manufacturing. We hypothesize that the aquatic toxicity of metal-containing carbon-based nanomaterials is contributable to three aspects: (i) soluble metals released from metal-loaded nanomaterials, (ii) toxicity due to metal-free nanomaterials, and (iii) metals bound to the nanomaterials. This project will test these hypotheses with a goal of elucidating whether the interaction between heavy metals and carbon-based nanomaterials will neutralize or promote the aquatic toxicity, or have no effect to sediment-dwelling organisms.
The research in the first year, as reported in the Year 1 report, focused on: (i) acquisition, manufacturing, and characterization of testing materials; (ii) establishment of the standard operation procedure for toxicity testing; and (iii) development of short-term methods for estimating the chronic toxicity of nanotubes.
In the second year, we evaluated the toxicity of different CNT materials to the amphipods (Hyalella azteca), the midge (Chironomus dilutus), the oligochaetes (Lumbriculus variegatus), and mussel (Villosa iris) in a phased approach. Tests conducted include (1) 14 -day toxicity tests of CNT in water with four selected organisms; (2) 14-day tests with CNT-containing sediments for the identified sensitive species in Phase 1; and (3) sediment tests with different concentration of CNTs and sediment types.
From the water-only exposure tests, we found that: (1) sonicated or non-sonicated as-produced single-walled and multi-walled CNTs are toxic to amphipods, midge, oligochates and mussels in water; (2) the observed toxicity is partially contributed to toxic metals dissolved from the nanomaterials, but also is caused by purified nanomaterials (effect on growth). Factors affecting the toxicity include the nature and sources of the nanomaterials, whether the nanomaterials are pre-treated or not, and the specific testing organisms.
Whole-sediment toxicity tests were conducted with amphipods (Hyalella azteca) exposed for 14 days to CNTs spiked with sediments up to 1% on dry weight basis. Eight reference sediments were evaluated with broad ranges in concentrations of total organic carbon or acid volatile sulfide. Survival of amphipods was typically not affected with exposure to CNT spiked in the sediment samples. However, the total biomass was significantly reduced in some sediment samples containing 1% CNTs. Concentrations of 0.1 and 0.01% MWCNT spiked in one soil also significantly reduced biomass of amphipods. These results demonstrate that growth was a more sensitive endpoint than survival for the amphipods, and the nature of sediments influences the toxicity of the CNT spiked in sediment.
In the third year, we plan to further test the toxicity of CNTs in the presence of sediments. We will use 28-day tests to assess if sub-lethal effect could be better demonstrated in the longer duration. Substantial effect will be devoted to publish research results in archived journals in conjunction with the preparation of a Ph.D. dissertation by Mr. Joseph Mwangi, who is expected to graduate by the summer 2010.
Journal Articles on this Report : 3 Displayed | Download in RIS Format
|Other project views:||All 16 publications||3 publications in selected types||All 3 journal articles|
||Hua B, Yang J, Zheng J, Deng B. Characterization and dissolution of metal impurities in multi-walled carbon nanotubes. Journal of Environmental Monitoring and Restoration 2008;5:92-98.||
||Mwangi JN, Wang N, Ritts A, Kunz JL, Ingersoll CG, Li H, Deng B. Toxicity of silicon carbide nanowires to sediment-dwelling invertebrates in water or sediment exposures. Environmental Toxicology and Chemistry 2011;30(4):981-987.||
||Mwangi JN, Wang N, Ingersoll CG, Hardesty DK, Brunson EL, Li H, Deng B. Toxicity of carbon nanotubes to freshwater aquatic invertebrates. Environmental Toxicology and Chemistry 2012;31(8):1823-1830.||