This article originally appeared on FoodPrint. Plastic is ubiquitous in supermarkets. Produce packaged in clamshell containers; water bottles and jugs, peanut butter canisters, salad dressings in plastic bottles and jars; and pasta boxes with miniature plastic windows line almost every shelf. Those small pieces of plastic in your shopping cart add up to mountains of plastic waste. The U.S. generates 42 million metric tons of plastic waste each year and most ends up in oceans or landfills where it takes up to 500 years to break down. Your weekly shopping trip generates a significant portion of plastic waste. Advertisement: "Supermarkets are where the average consumer encounters the most throwaway plastics," says John Hocevar, marine biologist and oceans campaign director for Greenpeace USA.