No day at the beach Derrick Z. Jackson

WHAT MOST amazed Ryan Prothro was how Coast Guard Beach in the Cape Cod National Seashore had ''more trash than you could imagine."

''Much of the trash has been covered by sand that the winds blows up from the beach," she wrote afterward. ''Not only was there so much trash, but the objects that you find are ridiculous. Our Scout troop found shoes, vodka bottles, a lot of styrofoam, and even tampon applicators. Seeing as there was so much trash, I am very surprised that there aren't more health issues around the wildlife."

All the jaws dropped among the 15 boys and girls and two other adults in our Boy Scout troop and Venture crew from Cambridge. It was the first weekend of April. The trip was supposed to be one where we combined a slide show about the piping plover with bike-riding. We also planned a 5-mile beach hike where we would clean up debris from winter along the way.

We never made it past a quarter-mile from the beach parking lot. There was that much trash. Nessarose Schear was so impressed with how much plastic, glass, and styrofoam drifted onto the beach over the winter that she decided to count up how many pieces of debris we picked up. It was 456.

''I know that some of it, like the buoys, might have broken off their ropes and floated ashore," Schear wrote in a reflection about the cleanup. ''But juice, milk, and other bottles must have been tossed into the ocean by uncaring people. Most of the trash we found should have been recycled by the owners. We found random items like a car fender and an oil can that somehow was dropped in the ocean."

If people shared the shock of Schear and Prothro, we would be on our way to cleaner beaches and a less blighted planet. They received a firsthand lesson in how trash can circulate for hundreds and even thousands of miles to a final resting place that, in our case, altered our whole day. Many people have the misconception that most of it comes from careless boaters and fishermen.

That actually accounts for only 20 percent of the trash. According to last year's report by the US Commission on Ocean Policy, 80 percent of marine debris actually began as land trash, a lot of it carelessly thrown down onto sidewalks and streets, bag by bag, plastic bottle by plastic bottle, where it is eventually washed down into sewers by rain.

A glimpse of how much trash human beings throw out into the ocean comes every fall in the Ocean Conservancy's International Coastal Cleanup day. Last year a half-million volunteers picked up 3.7 million pounds of debris from American coastlines and 7.7 million pounds worldwide. One marine researcher, Charles Moore, discovered in the late 1990s a spot far out in the Pacific Ocean where the currents and winds draw plastic debris into concentrations of a million pieces per square mile. Of course, no one knows what the ultimate result of all this plastic trash will be, since it will take hundreds of years for it to degrade.

The boys and girls on Coast Guard Beach did not have to see a million parts per square mile to be appalled. ''What gives people the right to throw their stuff away in the dune?" wrote David Goldfarb, our troop's senior patrol leader. ''Do they not care, or do they think someone like us will come along and pick it up and throw it away for them?"

Tsekai English wrote, ''I can't imagine how the birds on the ground feel."

Marcel Moran wrote: ''When one thinks of a Cape Cod beach, they think of fun in the sun, endless dunes and seasonal breezes. However, instead of darting to and fro in the waves, I had to dodge cans of bug spray and old fish netting. In a place that is supposed to be thick of the smell of salt water, all I could smell was soggy candy wrappers."

Moran added that because ''countless others have not taken the time to do the little things, like throwing a bottle in the trash, they've built up the trash to a point where a beautiful natural beach looks more like a city street on trash day."

These youngsters hope this summer that you do the little things so the next time they go to the beach, they can actually enjoy it.

Derrick Z. Jackson's e-mail address is jackson@globe.com.