With some 300 million tons of plastic products produced annually, it is not surprising that plastic is ubiquitous debris in the environment. Plastic bags hang in the trees in New York City and blow across the barren lands of the Mojave desert. Discarded plastic is found on remote islands in the South Pacific, where one study found an average of 240 items on (or buried beneath) each square meter of beach. Much of the plastic in the oceans is expanded polystyrene, better known as Styrofoam. Plastic wastes harbor microbial populations that degrade coral reefs, already under stress from warmer temperatures and greater acidity of seawater.
The Church of England has asked its parishioners to give up plastic for Lent. Like booze, sex and profanity, plastics have become a sin.
I’ve blogged about the problems of plastic before (http://blogs.nicholas.duke.edu/citizenscientist/i-just-want-to-say-one-word-to-you-just-one-wordplastics/); this is an update.
Most plastic is used in packaging and not recycled after use. We’ve all seen pictures of plastic wrappers strangling sea turtles, and plastic “nurdles” that crowd the digestive track of many seabirds. Under receipt of ultraviolet light from the sun, many plastic products degrade to smaller fragments that are less obvious in the environment. The average piece of discarded plastic lasts about 20 days in the open ocean, but small plastic particles can persist for centuries in the sediments. We should be thankful for this process, or we’d be knee deep in discarded plastics. On the other hand, degraded fragments of plastic, which are known as microplastics and nanoplastics, can enter organisms from their air and water. Degradation of plastics in the environment converts plastics from big, ugly debris that we can see to small unnoticed particles that may affect the health of humans and aquatic organisms.
Runoff waters frequently contain microplastic particles, which are not removed by sewage treatment plants. Microplastic particles and fibers are found along the coastline of the southeastern U.S., with an origin in runoff waters. The waters of the Great Lakes contain an abundance of microplastic particles that are accumulated by fish and shellfish and passed into the food chain, including humans. A recent paper reported that 73% of fishes caught in the North Atlantic west of Newfoundland contained microplastics in their gut.Particles of microplastic contaminate canned foods, such as sardines. Nanoplastic particles in the air are inhaled by humans, causing lesions in the respiratory system.
Plastics have brought safety and convenience to modern life, but the widespread contamination of nature with small particles of plastic has the potential to affect our health in ways that we are just beginning to understand. Even when Lent ends, there will be no substitute for recycling plastics and disposal of plastic in ways that do not produce uncontrolled contamination of our environment.
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