June 26, 2009: Researchers in South Carolina are raising red flags about the potential impact of nanoparticles, by tracking how easily they can distribute through a marine ecosystem and up the food chain.
The paper, published this week by the journal Nature Nanotechnology, highlights work from scientists at the University of South Carolina’s Nanocenter and the National Oceanic and Atmospheric Administration’s Coastal Center for Environmental Health and Biomolecular Research (CCEHBR), who note that nanoparticles can move easily into the marine ecosystem, absorbed and transferred from marsh grasses to biofilms and into filter-feeding species such as clams.
The group introduced gold nanorods (selected for their traceability) into three lab replications of a coastal estuarine ecosystem, complete with a tidal marsh creek and sea water, sea grass in sediment, microbes, biofilms, snails, clams, shrimp, and fish. From the paper abstract:
A single dose of gold nanorods (65nm length × 15nm diameter) was added to each mesocosm and their distribution in the aqueous and sediment phases monitored over 12 days. Nanorods partitioned between biofilms, sediments, plants, animals and sea water with a recovery of 84.4%. Clams and biofilms accumulated the most nanoparticles on a per mass basis, suggesting that gold nanorods can readily pass from the water column to the marine food web.
The study’s main take-away appears to be that more work is needed to more specifically determine how nanoparticles are transported and distributed through a marine environment. “We did not look at what happens ‘up the food chain,” noted CCEHBR director Geoff Scott, in a statement discussing the study and its results. But this preliminary work suggests a clear need to understand the impact on nanoparticles on shellfish and fish which humans eat. One interesting observation along these lines: the clams “accumulated a significant amount of the nanomaterial,” Scott noted.