麻豆淫院

(麻豆淫院Org.com) -- When nanoparticles from consumer products leach into the ocean, they may harm oysters and mussels.

Manufactured nanomaterials can be found in such diverse applications as electronics, cosmetics, paints, and even medicines, but their effects on the environment remain largely unknown. In a new laboratory study, scientists have found that saltwater oysters and mussels take up and retain significant amounts of manufactured nanoparticles from seawater in clumps of so-called 鈥渕arine snow.鈥�

鈥淣anomaterials are being used in increasing amounts, and it鈥檚 likely they鈥檙e being released in increasing amounts into the environment, including the ocean,鈥� says Evan Ward, professor of marine sciences at UConn鈥檚 Avery Point campus. 鈥淎s we develop these technologies, we need to be cautious, we need to know where the particles are going, and we need to know how they affect marine organisms.鈥�

Nanoparticles are tiny versions of common materials that have a diameter of less than 100 nanometers, or about four millionths of an inch. Their tininess gives them properties that normal-sized particles don鈥檛 have: for example, their large surface area for their size makes them stronger, lighter, and more reflective, making them ideal for reinforcing metals, increasing the SPF in your sunscreen, and producing paint that improves your home鈥檚 energy efficiency.

Some scientists, however, are concerned that these very properties could also make manufactured nanoparticles dangerous. When products break down in landfills, nanoparticles can wash away into soils, waterways, and the ocean, potentially creating hazards to animals and plants.

鈥淪ome materials that one would assume are safe can in fact cause damage to cells in their 鈥榥ano鈥� form,鈥� Ward says.

Ward studies the environmental physiology of oysters, mussels, and their relatives, which use their gills as specialized filters to take up food from ocean water. Although nanoparticles themselves are too small to be captured in large amounts, Ward鈥檚 study focused on how the bivalves鈥� feeding ecology affected their rate of uptake.

鈥淚n our study, we took into account how nanoparticles are likely to be delivered to the animals in the natural environment,鈥� he says. 鈥淲e asked, 鈥榃hat鈥檚 the setting in which they will be exposed to these particles?鈥欌��

Materials rarely exist as individual particles in the ocean, says Ward; instead, ocean currents bind up particles and sticky organic matter into aggregates that scientists call 鈥渕arine snow.鈥� These aggregates then sink to the bottom, where filter feeders like bivalves ingest them.

In their paper, published in Marine Environmental Research, Ward and coauthor Dustin Kach, a former UConn graduate student, used natural seawater to produce marine snow that contained fluorescently labeled polystyrene nanoparticles. They then exposed oysters and mussels collected from the Long Island Sound to this snow-filled seawater.

The researchers found that nanoparticles were taken up in much higher amounts when the bivalves were exposed to marine snow. But they also found that when filtered from marine snow, nanoparticles remained in the bivalves鈥� bodies for a much longer time than would be expected for non-nutritive materials: up to three days.

Ward suspects that the particles are being treated as food by the animals, and are being taken up into their digestive cells. This could be particularly dangerous, he says, since small nanoparticles can circumvent living cells鈥� natural defenses.

鈥淏ecause of their high surface area, manufactured nanoparticles can strip off electrons from other compounds and create free radicals,鈥� he says. 鈥淧articles like these can cause havoc in cells.鈥�

Ward sees his work as a first step in understanding the potential issues associated with manufactured nanoparticles. He emphasizes that further work is needed to determine the amounts of manufactured nanoparticles in seawater and their levels of toxicity to living things.

鈥淩ight now there are few techniques to identify manufactured nanomaterials in the natural environment because they鈥檙e so darn small,鈥� he says. 鈥淲ith these studies, we hope to demonstrate potential problems to keep in step with the use of nanomaterials. Then when techniques are available to sample them in the wild, we鈥檒l be prepared to say whether or not we should be worried.鈥�