关于塑料袋的英文文章

Plastic and the Food Chain
Plastic Accumulates in Rivers, Oceans, Fish, and Us
作者：Sara E. Lewis
Sep 10, 2007
Plastic is man-made -- not easily broken down or reabsorbed by the environment. Clean-ups, consumer awareness, and alternative materials are needed.
News about plastic compounds in pet foods and toothpaste from China caught headlines in 2007. Afterwards, the USDA and FDA reported that they are investigating and testing a variety of imported food additives. Officials assured the public that, “The inspections are a precautionary measure to ensure the safety of products entering at U.S. ports of entry. There is no evidence to suggest products bound for the human food supply are contaminated.”
But the truth is that recent worries about plastics are the tip of the iceberg. Researchers have been concerned for some time about chemical compounds that make up plastic materials getting into the food supply. Plastic is the word we use to describe the many types of man-made or synthetic materials that become toys, containers, and more.
History of Plastic
Since the 1960s, plastics have become omnipresent. Many useful products that save time, reduce accidental injury, and improve quality of life are made from plastic. At the same time, there is no known organism that breaks down plastic in the environment, so every bit of plastic that has ever been made is very likely to be still with us. Estimates of how long it will take plastics to be reabsorbed by the environment range from 400 years to a much longer unit of geologic time.
History of Concern about Plastic in the Environment
By the 1980s, people worldwide began to notice the mess of plastic that was washing up on beaches and the harm it was doing to birds and animals that became tangled in fishing line and 6-pack rings. Initiatives like the Chesapeake Bay Foundation’s Clean the Bay Day program were organized to clean up debris on the beaches. While many participants saw such events as tidying up exercises, organizers have understood that they are also important initiatives aimed at keeping some plastic out of the food chain. According to the Chesapeake Bay Foundation, “shoreline litter is not just a public eyesore, it is harmful to wildlife, a source of toxic water pollution, and symptomatic of other, less visible forms of pollution entering local waterways.”
In England, University of Plymouth marine biologist Richard Thompson has combed the beaches since the 1980s and discovered dead birds with so many small pieces of plastic in their stomachs, probably scooped up mistakenely for food, that they likely died from starvation or blockage of the intestines.
Ten years ago, Captain Charles Moore of the Algalita Marine Research Foundation, on a trip across the Pacific Ocean after a sailing race, saw a patch of floating plastic debris in the North Pacific Gyre. This area of slow swirling current is said to be the size of the state of Texas. There are several such gyres where plastic floats around and around and is swept in and out by currents and tides. All the while, the mixed debris of such things as plastic bags, bottles, buckets, and toys is eroding into smaller and smaller pieces.
Both scientists and others have trawled to collect water samples and sort the debris to determine how many of the small particles in oceans and rivers are plastic. One-third and more of the samples contain tiny plastic pieces of the sort that birds and fish often see as their food. These researchers have found tiny particles of plastic embedded in the tissue of dead animals.
Plastics, Eating Fish, and Your Health
Captain Moore said, “The base of the food chain is being displaced by a non-digestible, non-nutritive component which is actually outweighing and outnumbering the natural food. That is our core issue.”
As the persistence of plastics in the environment becomes better understood, consumers are questioning the safety of eating fish. The Mayo Clinic answers that, “As good as fish are for your health, be aware of potential downsides. Some types of fish may contain significant amounts of contaminants, such as mercury, polychlorinated biphenyls, dioxins or other chemical pollutants. Fish acquire these toxins from pollutants in lakes, rivers and oceans.”
More research is needed to determine the ultimate consequence to humans of the accumulation of plastic that can concentrate toxic chemicals. But Neil Seldman of the Institute for Local Self Reliance has said that plastic is a bigger danger than global warming because it is killing the lowest common denominator in the food chain. The problem can only be eased when greater public awareness results in less use of plastic. Manufacturers who acknowledge the problem are looking into ways to create degradable plastics.
What You Can Do to Reduce Plastic in the Environment
In the meantime, the most effective way to limit the amount of plastic entering the food chain is beach cleaning. Also, consumers can look for alternative materials and avoid excessive use of single-use plastic bottles, containers, and packaging. Finally, by recycling, we can extend the useful life of plastic products.
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