A man-made nanoparticle is a new-age material too tiny to believe. But it's about to make you very uneasy.

Researchers in South Carolina have found that nanoparticles in manufactured goods can work their way through the waste stream into coastal waters and collect in plants and animals, such as marsh grasses or clams.

"Clearly this warrants concern" for seafood safety and maybe human health, said Geoff Scott, director of the federal Center for Coastal Environmental Health and Biomolecular Research at Fort Johnson, who took part in the study.

Nanoparticles are materials such as metals produced at sizes not much bigger than molecules. They are made so small that their properties change — they literally become broader and more flexible.

They are the latest "hot" industrial technology — used in everything from cosmetics to hearing aids. They show particular promise for biomedical devices, such as stents that release drugs into tissues in the artery or diagnostic machines that sort cancer cells from healthy cells.

They have become a $200 billion industry and are expected to become a $3 trillion industry in the next five years.

Nobody knows yet what their impact might be on the environment or marine or human health; some early research has indicated risks to the lungs and cardiovascular system, among other toxicities.

The study on coastal effects was just released by the University of South Carolina Nanocenter and the National Oceanic and Atmospheric Administration's labs at Fort Johnson.

"We don't really know yet (what it means for people). It's fair to say the growth, the economic impact of nanoparticles is happening very rapidly," said John Ferry, a chemistry and biochemistry associate professor at the university, who also took part in the study. "It's fair to say environmental impacts track economic impacts."

For example, Ferry said, petrochemicals have become so widespread that you not only see the products all around as you drive down the road — they are the road. "There's almost no place left we don't see the (environmental) impacts of petrochemicals."

The study was done in an "estuarine mesocosm" in the lab — essentially a tank that mimics real world effects, such as tide.

In the real world, man-made nanoparticles are hard to detect among the countless tiny particles in a substance, Ferry said.

Researchers used a gold nanorod because it was easier to track.

Scott was surprised at how much of the material was picked up by clams.

Ferry was surprised at how the particles stuck to biofilm, the gook that shows up on every wetted surface from rocks in a stream to your teeth. Creatures like snails eat it like grass, Ferry said. "Once (nanoparticles) are in the biofilm, the clock is ticking."

The finding is one more alarm sounded by coastal research at Fort Johnson, following studies in 2008 that found high concentrations of man-made antibiotics, as well as the byproducts of commercial flame retardants and stain repellents, in dolphins.

Environmental research has tended to follow environmental disasters, Ferry said. The research on particles like these gives people a chance to do something about the impact before a disaster happens.

"Every one of these studies found levels more than we expected," Scott said.

"Each class of emerging contaminants of concern is going to require review and analysis. We need to see how they behave in the environment and what we should do about it," he said.