Lost at Sea: Where Is All the Plastic?

摘要

Millions of metric tons of plastic are produced annually. Countless large items of plastic debris are accumulating in marine habitats worldwide and may persist for centuries. Here we show that microscopic plastic fragments and fibers (Fig. 1A) are also widespread in the oceans and have accumulated in the pelagic zone and sedimentary habitats. The fragments appear to have resulted from degradation of larger items. Plastics of this size are ingested by marine organisms, but the environmental consequences of this contamination are still unknown. Over the past 40 years, large items of plastic debris have frequently been recorded in habitats from the poles to the equator. Smaller fragments, probably also plastic, have been reported but have received far less attention. Most plastics are resistant to biodegradation, but will break down gradually through mechanical action. Many "biodegradable" plastics are composites with materials such as starch that biodegrade, leaving behind numerous, nondegradable, plastic fragments. Some cleaning agents also contain abrasive plastic fragments. Hence, there is considerable potential for large-scale accumulation of microscopic plastic debris.