Silver nanoparticles are used in all kinds of products—from odor-fighting socks to self-sanitizing toothbrushes—but some researchers fear they may be bad for the environment and our personal health, the New York Times reports. First, the good news: Microscopic particles of silver kill off bacteria, which is why they're used in 383 consumer products, reports the CBC. But studies of silver nanotechnology are uncovering possible health risks too, like cellular damage, particles crossing the blood-brain barrier or getting past our outer layer of skin. "There’s evidence that the particles penetrate into plasma membranes, and they can disrupt cell function," said an expert.
That said, scientists are even more worried about environmental threats when products are washed and silver flows into our water supply; a study of low-level silver contamination of a natural environment showed damage to plants and aquatic creatures. Some experts also question the point of silver nanoparticles, saying bacteria may adapt to the nanotechnology, or people may be too fearful of bacteria in the first place, the Chicago Tribune reports. On the other hand, the silver industry says concerns are exaggerated and silver has been used in drinking-water purification and swimming pools since the 1970s. "It's the most sustainable and by now the most researched and safest biocide technology on the market," said the CEO of a nanosilver company. (For more, read about a possible cancer risk for nanotech factory workers.)