Via the August 18, 2006, issue of The Week, from an opinion piece in the LA Times by Niall Ferguson:

It was 99 years ago that Leo Hendrik Baekeland invented the first plastic based on a synthetic polymer — Bakelite — and ushered in the age of plastic. From that moment, a new kind of pollutant entered the sea; one that took a century or more to degrade.

The plastic plague is a global epidemic. According to the United Nations Environment Program, about 46,000 pieces of plastic are floating on every square mile of the world's oceans.

The problem is more than merely aesthetic. Last week, this newspaper carried a shocking report from Midway Atoll, which is about as isolated a spot as the world has to offer. Hardly anyone lives there, so the number of bottles thrown in the sea can't be large. And yet birdlife on Midway is being devastated as albatrosses inadvertently feed their chicks lethal fragments of plastic picked up from what's known as the Eastern Garbage Patch, a virtual island of trash formed by the currents of the North Pacific subtropical gyre.

The Eastern Garbage Patch on Wikipedia.