Environment

Awash in Plastic: Oceans May Hold 250,000 Tons of Trash

The world's oceans may contain about 10 times more plastic than the most recent studies suggest. The new figure estimates that the oceans hold more than 250,000 tons of trash, a number vastly different from a past estimate, which suggested the oceans' plastic is mysteriously disappearing.

Scientists arrived at the new number by combining visual estimates of trash volume with data collected from trawling the oceans with nets, said study co-author Markus Eriksen, director of research for the 5 Gyres Institute, an organization aiming to understand the plastic pollution in the ocean.

The detritus of everyday life has been pouring into the oceans for decades. Everything from plastic bags to water bottles have migrated from the coastlines, harbors and river mouths into the oceans, where gyres, or the ocean's giant conveyor belts, carry them to the most remote stretches of the seas.

About 15 years ago, scientists discovered the Great Pacific Garbage Patch, a trash-filled region of the Pacific Ocean the size of Texas. A recent excursion even found that islands of trash were forming in the garbage patch.

The team combined both visual plastic surveys and net hauls with mathematical models for how ocean circulation would transport plastic, and compared these results based on the size categories of the plastic garbage. The new estimates suggest that about 5.25 trillion plastic particles, weighing about 269,000 tons, litter the oceans. Nearly 75 percent of that weight came from large plastic objects such as buoys, buckets and other fishing gear. The model also suggests that ocean circulation acts like giant shredders, breaking down large plastics that predominate at the coastlines into smaller bits, with the tiniest pieces overrepresented in the subpolar regions.