Trashed: across the Pacific Ocean, plastics, plastics, everywhere

Natural History, Nov, 2003 by Charles Moore

Entanglement and indigestion, however, are not the worst problems caused by the ubiquitous plastic pollution. Hideshige Takada, an environmental geochemist at Tokyo University, and his colleagues have discovered that floating plastic fragments accumulate hydrophobic--that is, non-water-soluble--toxic chemicals. Plastic polymers, it turns out, are sponges for DDT, PCBs, and other oily pollutants. The Japanese investigators found that plastic resin pellets concentrate such poisons to levels as high as a million times their concentrations in the water as free-floating substances.

The potential scope of the problem is staggering. Every year some 5.5 quadrillion (5.5 x [10.sup.15]) plastic pellets--about 250 billion pounds of them--are produced world-wide for use in the manufacture of plastic products. When those pellets or products degrade, break into fragments, and disperse, the pieces may also become concentrators and transporters of toxic chemicals in the marine environment. Thus an astronomical number of vectors for some of the most toxic pollutants known are being released into an ecosystem dominated by the most efficient natural vacuum cleaners nature ever invented: the jellies and salps living in the ocean. After those organisms ingest the toxins, they are eaten in turn by fish, and so the poisons pass into the food web that leads, in some cases, to human beings. Farmers can grow pesticide-free organic produce, but can nature still produce a pollutant-free organic fish? After what I have seen firsthand in the Pacific, I have my doubts.

Many people have seen photographs of seals trapped in nets or choked by plastic six-pack rings, or sea turtles feeding on plastic shopping bags, but the poster child for the consumption of pelagic plastic debris has to be the Laysan albatross. The plastic gadgets one typically finds in the stomach of the bird--whose range encompasses the remote, virtually uninhabited region around the northwest Hawaiian Islands--could stock the checkout counter at a convenience store. My analysis of the stomach contents of birds from two colonies of Laysan albatrosses that nest and feed in divergent areas of the North Pacific [see map on page 48] show differences in the types of plastic they eat. I believe those differences reveal something about the way plastic is transported and breaks down in the ocean.

On Midway Island in the Hawaiian chain, a bolus, or mass of chewed food, coughed up by one bird included many identifiable objects. By contrast, a bird on Guadalupe Island, which lies 150 miles off the coast of Baja California, produced a bolus containing only plastic fragments. The principal natural prey of both bird colonies is squid, but as the ecologist Carl Safina notes in his book Eye of the Albatross, the birds' foraging style can be described as "better full than fussy." Robert W. Henry III, a biologist at the University of California, Santa Cruz, and his colleagues have tracked both the Hawaiian and the Guadalupe populations of birds and found that the foraging areas of each colony in the Pacific are generally nonoverlapping and wide apart.