Scientists gather to study risk from microplastic pollution

Tiny bits of broken-down plastic smaller than a fraction of a grain of riceare turning up everywhere in oceans, from the water tothe guts of fish and the poop of sea otters and giant killer whales.

Yet little is known about the effects of these "microplastics" — onsea creatures or humans.

"It's such a huge endeavor to know how bad it is," said Shawn Larson, curator of conservation research at the Seattle Aquarium. "We're just starting to get a finger on the pulse."

This week, a group of five-dozen microplastics researchers from major universities, government agencies, tribes, aquariums, environmental groups and even water sanitation districts across the U.S. West is gathering in Bremerton, Washington, to tackle the issue. The goal is to create a mathematical risk assessment for microplastic pollution in the region similar to predictions used to game out responses to major natural disasters such as earthquakes.

The largest of these plastic bits are 5 millimeters long, roughly the size of a kernel of corn, and many are much smallerand invisible to the naked eye.

They enter the environment in many ways. Some slough off of car tires and wash into streams — and eventually the ocean — during rainstorms. Others detach from fleeces and spandex clothing in washing machines and are mixed in with the soiled water that drains from the machine. Some come from abandoned fishing gear, and still more are the result of the eventual breakdown of the millions of straws, cups, water bottles, plastic bags and other single-use plastics thrown out each day.

Research into their potential impact on everything from tiny single-celled organisms to larger mammals like sea otters is just getting underway.

"This is an alarm bell that's going to...