Keeping freshwater fresh. I’m Bob Hirshon and this is Science Update.
Road salt is the cheapest way to melt winter ice from streets. But in the long term, it may be the most expensive. Road salt corrodes bridges, guardrails and, of course, cars. And according to a new report by the US Geological Survey, it makes streams and rivers toxic to aquatic life. In fact, they found that salt runoff rendered more than half of the northern streams they studied toxic, and a quarter acutely toxic.
In other water quality news, developing countries have an urgent need for safe drinking water, but water treatment can be expensive. Stanford University scientists have developed an inexpensive system that uses cotton fibers infused with threadlike silver wires and carbon nanotubes. Connecting the material to a solar panel or car battery generates an electric field that sterilizes water as it passes through. I’m Bob Hirshon for AAAS, the Science Society.