Wastewater is a potential mine of valuable metals, according to researchers at the United States Geological Survey, who presented their findings Monday at the National Meeting & Exposition of the American Chemical Society. Consumers encounter metals everywhere in their daily life, including in hair care products, detergents, even nanoparticles that are put in socks to prevent bad odors. Their bodies absorb them, then eliminate at least part of them down the toilet. Silver is particularly common, followed closely by copper, lead and vanadium. Collecting the metals could generate revenue. Researchers hope it could also increase the percentage of non-toxic wastewater sludge that is used as natural fertilizer.