The Garbage Patch wasn’t merely a cosmetic problem, nor merely a symbolic one, Moore contended. For one thing, it was a threat to wildlife. Scientists estimate that every year at least a million seabirds and 100,000 marine mammals and sea turtles die when they entangle themselves in debris or ingest it. Plastic polymers, as has long been known, absorb hydrophobic chemicals, including persistent organic pollutants, or POPS, like dioxin, PCBs and DDT. Highly controlled in the US but less so elsewhere, such substances are surprisingly abundant at the ocean’s surface.

By concentrating these free-floating contaminants, Moore worried, particles of plastic could become “poison pills”. He also worried about toxins in the plastic itself—phthalates, organotins—that have been known to leach out over time. Once fish or plankton ingest these pills, Moore speculated, poisons both in and on the plastic would enter the food web. And since such toxins concentrate, or “bioaccumulate,” in fatty tissues as they move up the chain of predation—so that the “contaminant burden” of a swordfish is greater than a mackerel’s and a mackerel’s greater than a shrimp’s— this plastic could be poisoning people too.

In the scientific community, Moore’s work is somewhat controversial. Even marine biologists who share his alarm have misgivings about the sensationalism around the Garbage Patch. Since the plastic debris in the North Pacific convergence zone is spread out unevenly across millions of miles of ocean, and since most of it is fragmentary, flowing through the water column like dust through air, the Garbage Patch bears little resemblance to a floating junkyard. But it is, numerous scientists assure, very much for real.
-DONOVAN HOHN (New York Times)