Among twigs and seaweed fibers in his fistful of sand are a couple dozen blue and green plastic cylinders about two millimeters high.

“They’re called nurdles. They’re the raw materials of plastic production. They melt these down to make all kinds of things.” He walks a little farther, then scoops up another handful. It contains more of the same plastic bits: pale blue ones, greens, reds, and tans. Each handful, he calculates, is about 20 percent plastic, and each holds at least thirty pellets.

“You find these things on virtually every beach these days. Obviously they are from some factory.”

However, there is no plastic manufacturing anywhere nearby. The pellets have ridden some current over a great distance until they were deposited here—collected and sized by the wind and tide.