More trash talk

Natural History, May, 2004 by Steve E. Hartman, Guy Ottewell, Allan J. Sander

According to Charles Moore ("Trashed," 11/03), gyres have pulled our oceangoing plastic detritus into localized concentrations. Is there any reason the nations of the world couldn't organize a cleanup at appropriate intervals?

Steve E. Hartman

Saco, Maine

Charles Moore describes an appalling situation, but leaves some questions unanswered. How does the plastic get into the ocean? How fast is it building up? And what is being done--or what should be done--about it?

Guy Ottewell

Lyme Regis, England

I understand that some bacteria aid in cleaning up oceanic oil spills. Is there any such organista that can break down these oil-based pollutants?

Allan J. Sander

Trabuco Canyon, California

CHARLES MOORE REPLIES: Efforts are under way to accomplish something like what Steve E. Hartman envisions, principally asa way to protect the critically endangered Hawaiian monk seal from entanglement in derelict fishing nets.

Unfortunately, I do not believe this action will stop the buildup of plastic particulates, the photo-degraded bits of plastic trash that now outweigh plankton in much of the ocean. Plastic particles, which are nearly the same density as seawater, are mixed into the entire ocean. No cleanup of the 1.37 billion cubic kilometers of seawater is possible. The only cleanup possible is to attack the problem at its source.

In reply to Guy Ottewell, the farther you get from civilization, the more closely associated plastic debris in the ocean is with the fishing industry. But 80 percent of the total debris comes from landbased sources, not all of them near the coast (much is carried to the ocean from far inland, by rivers). The plastic industry itself accounts for millions of preproduction plastic pellets, as well as much plastic dust and sawdust from transfer, molding, and recycling operations--small bits less than five millimeters across that are hard to control. During the 1990s, Haruo Ogi of Hokkaido University found a tenfold increase of plastic particles in his trawls off Japan.

Currently the gyre has an average of one particle per square meter in areas of high concentration. In windblown collections of debris, the surface is more than covered. Plastics need to be designed for recycling, and those who make them should be prepared to take on that responsibility.

In response to Allan J. Sander, I know of no bacteria that eat consumer plastics, but, in any case, toxic chemicals are too dispersed in the ocean to be addressed by the techniques that are used in concentrated spills.