Single-walled carbon nanotube (SWNT) toxicity, bioavailability, and effect on co-contaminants in a benthic estuarine system

Single-walled carbon nanotubes (SWNT) are unique manufactured carbon nanomaterials used in a variety of consumer and electronic products.  If released into the aquatic environment, these materials may cause deleterious effects on organisms such as fish and invertebrates.  Previous work in our laboratory has shown that SWNT associate with natural particulate matter, and will therefore likely deposit in sediments after discharge to the aquatic environment. The objective of this research project is to assess the toxicity and bioavailability of SWNT to benthic organisms as well as their effect on the toxicity and bioavailability of co-contaminants.

Toxicity and bioaccumulation are being assessed through sediment and food exposure routes in several benthic invertebrates including Ampelisca abdita, Americamysis bahia, Leptocheirus plumulosus, Mercenaria mercenaria, and Nereis virens. SWNT body burdens in organisms are determined using a novel near infrared fluorescence (NIRF) spectroscopy method developed by our laboratory, and in parallel experiments using 14C-SWNT radiotracers.

SWNT are hydrophobic structures and other hydrophobic organic contaminants (HOCs) have been shown to strongly sorb to the surface of SWNT. Our lab is investigating whether SWNT will decrease the bioavailability of these HOCs through sorption, or whether they will act as vectors that increase the HOC body burden in benthic organisms. We are also interested in examining the influence of SWNT electronic structure (e.g. metallic vs semiconducting) on both biological uptake of the SWNT and sorption of HOCs to these nanomaterials.

These experiments contribute toward the overall goal of determining the environmental impact of SWNT in a benthic estuarine system. Environmental release is inevitable, and it is important to determine any detrimental effects before they occur so that regulations can be put in place to minimize these effects.