Contact lenses flushed in toilets or washed down sinks each year in the United States add up to between six to 10 million tons of plastic, eventually adding to the troubling amounts of plastic waste in the world’s waterways and oceans. Those plastics and the chemicals in them can have detrimental effects on the food chain among aquatic organisms, animals and humans, says Fulton Schools Professor Rolf Halden, an environmental engineer who presented his lab’s research on plastics pollution at a meeting of the American Chemical Society. Without widespread efforts to safely recycle plastics and reduce their use overall, the threat of increasingly significant environmental damage will grow.