Thousands of volunteers plan to pick up trash on Saturday from 9 a.m. to noon during Coastal Cleanup Day. It’s the largest single-day volunteer event in the world.

Los Angeles County’s coastlines, rivers and creeks will contain 66 designated cleanup sites. This year, scuba divers and kayakers will join volunteers who collect trash on foot.

Meredith McCarthy of Heal the Bay said that in previous cleanups, volunteers have found pumpkins full of hard-boiled eggs, suitcases full of graham crackers, chip bags, popsicle sticks and more. She said about 80 percent of the trash along our beaches comes from inland sources.

“If somebody in Whittier throws a styrofoam cup, or it falls out of a trash can in Sherman Oaks, it’s going to blow down the street into the storm drain and it eventually finds its way to the nearest river or creek and it’s heading straight out to the beach," she said. "So, all of that trash ... it doesn’t matter where you live, you have an immediate impact on our ocean health.”

McCarthy said inland areas including the Dominguez Channel and the L.A. River confluence will especially need help. Her organization calls them “code red” cleanup sites.

“If you have small kids, the beaches are great places, but if you really want to get into it, the code red sites are where we need your help," McCarthy said. "In those inner rivers and waterways, there isn’t a municipality in charge of it so they tend to have a lot of trash."

Volunteers include groups from schools and businesses, sports teams and more. L.A. County volunteers raked in 137,000 pounds of garbage last year.