During the past half-century, a growing portion of what we eat, drink or use has come in plastic packaging - petroleum-based containers that are sturdy and long-lasting, yet are used only briefly and then thrown away.  Daily, we use and discard billions of plastic bags and bottles, and much of this trash ends up littering the environment or, increasingly, being washed out to sea. Many scientists have documented the growing volume of plastic garbage floating in the oceans.  Now a young couple is taking a fresh look at the problem to see if something can be done to solve it.