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(单词翻译:双击或拖选)
Divine Ntaryike | Douala, Cameroon
05 October 2010
Across Africa, plastic bags blemish1 rural and urban scenery, damage ground water and soils, and choke livestock2 and fish, entangle3 birds and threaten animals in general. They also block sewage pipes, turning them into safe havens4 for mosquitoes, which cause malaria5.
They're cheap and people don't give a thought to throwing them away, but it takes a thousand years for them to decompose6. When they do degrade, they break into small toxic7 particles that contaminate water and soils.
The UN Environment Program, UNEP, estimates that some four or five trillion plastic bags are manufactured worldwide every year, with only one percent being recycled.
Now Nigerian scientists are looking at ways to beat the scourge8 with biodegradable plastic bags.
The work is being done at the Biotechnology Advanced Laboratory in Abuja, a part of the government's Sheda Science and Technology Complex.
Researchers are working to embed9 biodegradable starch10 in polymers, which are used to make plastics. Next, they identify microbes that would feed on the starch and cause it to break down completely into organic material, which would then be assimilated back into the soil.
Prof Godwin Ogbadu is director of the Abuja-based Biotechnology Advanced Laboratory.
"In this case, he says, "the microorganism we have isolated11 will use the polymer as its food and will dissolve it."
The Nigerian approach is not the only one. In South Africa, experts are developing plastic bags that dissolve into water and carbon dioxide in prolonged exposure to sunlight.
In Mali, experts are working using them to make paving stones.
Some governments are passing laws to ban or curb12 the use of plastic bags. Several economists13 argue that restrictions14 will lead to unemployment and revenue loss, while others say it will save millions of barrels of oil used in producing plastic bags.
They also say there may be economic gains.
Dr. Shola Odusanya is deputy director on the Biotechnology and Genetic15 Engineering Laboratory, part of the Sheda Science and Technology Complex. He and his colleagues are working to reduce the amount of plastic waste with a process that breaks it down into powder. The Nigerian scientist says,
"The process involves using some proprietary16 solvents17 we want to keep secret because this is a potentially very big commercial project. One of the uses of this is water-repellent paint. Actually, one of our colleagues has developed paint based on this material."
Odusanya says the project will become marketable and will create new jobs. Litter bins18 for plastic waste will be set up nationwide, and people will be recruited to search through the dumps for plastics.
In some countries, like Cameroon, waste management systems are inadequate19 and environmental laws rarely enforced. In those cases, the approach is different. An eco-friendly artist, Nereus Patrick Cheo, has recruited an army of street children. Together they rake through foul-smelling refuse dumps for plastics, which Cheo transforms into flower jars, beads20, statues and murals.
For now, the bulging21 heaps of abandoned waste, especially plastics, remain. And so environmentalists are hoping Dr. Odusanya's project will be successful and can be used by scientists in other parts of Africa.
1 blemish | |
v.损害;玷污;瑕疵,缺点 | |
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2 livestock | |
n.家畜,牲畜 | |
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3 entangle | |
vt.缠住,套住;卷入,连累 | |
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4 havens | |
n.港口,安全地方( haven的名词复数 )v.港口,安全地方( haven的第三人称单数 ) | |
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5 malaria | |
n.疟疾 | |
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6 decompose | |
vi.分解;vt.(使)腐败,(使)腐烂 | |
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7 toxic | |
adj.有毒的,因中毒引起的 | |
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8 scourge | |
n.灾难,祸害;v.蹂躏 | |
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9 embed | |
vt.把…嵌(埋、插)入,扎牢;使深留脑中 | |
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10 starch | |
n.淀粉;vt.给...上浆 | |
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11 isolated | |
adj.与世隔绝的 | |
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12 curb | |
n.场外证券市场,场外交易;vt.制止,抑制 | |
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13 economists | |
n.经济学家,经济专家( economist的名词复数 ) | |
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14 restrictions | |
约束( restriction的名词复数 ); 管制; 制约因素; 带限制性的条件(或规则) | |
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15 genetic | |
adj.遗传的,遗传学的 | |
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16 proprietary | |
n.所有权,所有的;独占的;业主 | |
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17 solvents | |
溶解的,溶剂 | |
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18 bins | |
n.大储藏箱( bin的名词复数 );宽口箱(如面包箱,垃圾箱等)v.扔掉,丢弃( bin的第三人称单数 ) | |
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19 inadequate | |
adj.(for,to)不充足的,不适当的 | |
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20 beads | |
n.(空心)小珠子( bead的名词复数 );水珠;珠子项链 | |
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21 bulging | |
膨胀; 凸出(部); 打气; 折皱 | |
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