Grantee Research Project Results
Title of Talk:
Chemical and biological behavior of carbon nanotubes in estuarine sedimentary systems
Abstract of Talk:
Objectives: The general objectives of the proposed research are to:
- Determine factors controlling the fate of single-walled carbon nanotubes
(SWNTs) and their synthetic byproducts in estuarine seawater, sediment,
and sediment-ingesting organisms.
- Examine the impact of SWNTs and byproducts on the disposition of
model organic contaminants in estuarine sediments.
- Determine whether the presence of SWNTs and byproducts in estuarine
sediments affects the bioavailability of model organic contaminants
to estuarine invertebrates.
- Assess the toxicity of SWNTs and byproducts to suspension- and deposit-feeding estuarine invertebrate models in seawater suspension alone, and/or in combination with estuarine sediments.
Experimental Approach: Our research plan will address these objectives through a series of experiments designed to provide a holistic picture of the behavior of SWNTs and their synthetic byproducts upon entry into the estuarine environment. These experiments will include tracing the fate and phase-association of 14C-SWNTs and byproducts under simulated estuarine conditions and through ingestion by deposit-feeding organisms, batch sorption studies to examine the affinity of SWNTs for model hydrophobic organic contaminants (HOC) in the estuarine environment, laboratory-scale bioaccumulation experiments designed to test modulation of HOC bioavailability by co-occurring SWNTs in estuarine sediments, and dose-response experiments designed to test the potential for SWNTs and byproducts to directly cause adverse effects on a sensitive estuarine infaunal invertebrate (the harpacticoid copepod Amphisascus tenuiremus).
Results: The proposed work will, for the first time, address the physical, chemical, and biological behavior of novel and emerging carbon nanotube materials under environmental conditions typical of estuaries. In total, we will address not only the potential for SWNTs to be transported, accumulate, and cause direct deleterious effects within estuarine environments, but also the potential for linked effects on the biological and chemical behaviors of known priority pollutants common in estuarine sediments. This combined approach represents a novel way of addressing the environmental impact of an emerging synthetic nanomaterial and will thus provide the USEPA and the scientific community with an entirely new and highly relevant dataset for risk assessment of SWNT-derived contaminant discharge. Further, the work will generate new scientific knowledge related to the behavior of these highly novel nanomaterials under conditions not normally tested in the course of nanoscience research (e.g. non-mammalian biological systems, highly saline aqueous solutions, and complex sediment media). This knowledge may become useful in designing new nanoscale technologies in, e.g., environmental engineering or “green” manufacturing techniques.