Text 1. Killing fields

Power lines, computers, radar, microwave ovens and electric blankets are sources of non-ionising electromagnetic radiation and threaten the health of the users.

It is a bit more than 100 years since electricity generation started, about 80 years since the beginning of public radio transmissions and 60 years since radar was first used. Since the 1950s we began to surround ourselves with significant amounts of electromagnetic energy.

When radar was first introduced in World War II, it was such an important factor in the Allied victory that few raised questions of its biological safety: safety standards were set high enough to allow the military virtually unrestricted use of microwave and high-frequency radiation. American scientific reports from that time, suggesting that microwave radiation might cause leukaemia, cataracts, brain tumours and heart disease, were ignored.

When maximum exposure levels were set in the 1950s, they were mainly based on how much external power could be dissipated on the surface of the human body without causing a significant rise in body temperature. The validity of these and subsequent safety standards across the electromagnetic spectrum is now being challenged, both within the scientific community and, increasingly, in the courts. This has been brought about by the considerable number of research reports linking low-level alternating electric and magnetic fields with a variety of serious health effects. Particularly worrying are the reports about the effects of 50 Hz and 60 Hz power-line fields, low-frequency pulsed radar systems and high-power ELF (extremely low frequency) communication systems. Here is a selection of some of the report conclusions:

The risk of dying from acute leukaemia is increased by 2.6 if you work in an electrical occupation, especially if you are a telecommunication engineer or radio amateur.

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Service personnel exposed to non-ionising radiation when compared with their unexposed colleagues were almost seven times as likely to develop cancer of the blood-forming organs and lymphatic tissue.

10 to 15 per cent of all childhood cancer cases might be attributable to power-frequency fields, found in their homes.

Clinical depression and suicides were closely linked with living near power lines. Nevertheless, some countries still allow to build houses directly under high-voltage distribution cables.

(Adaptedfrom “Electronics World + Wireless World”)

Text 2. SPACE LITTER

When the space shuttle Challenger returned to Earth with a cracked windshield in June 1983, engineers assumed the culprit (винуватець) was a micro-meteorite - a stray piece of cosmic dust that could have hit the windshield at 44,000 miles (71,600 kilometres) per hour. But after examining the fracture (трицина) pattern and trace elements in the crack, scientists concluded that whatever Challenger ran into was man-made.

The case of Challenger’s windshield illustrates a serious concern among people who put spacecraft into orbit. So much debris (уламки) litters the space lanes that it poses a major collision hazard. Experts suspect that space collisions have destroyed several satellites, all of which had been in good condition. If the debris keeps accumulating, the chances of collision are greater. Thousands of objects the size of a baseball or larger, each circling Earth at 17,500 miles per hour, are now being tracked in space. Some of them are operating satellites but others are old rockets, fuel tanks or remnants of previous explosions and collisions.

A more serious threat are objects the size of golf balls. Even the third category of space garbage - tiny orbiting flakes, estimated to number in the billions - is potentially hazardous. They are the prime suspect in the case of the shuttle windshield, which was the first proof engineers had that space debris was a growing problem. A more convincing case came when another astronaut crew returned to Earth with parts of the Solar Maximum satellite they repaired in the orbit. There were 160 small craters in the layered plastic insulation. Most of the holes found in the plastic had been punctured by man-made objects.

Much of the space debris came from satellites’ and second-stage engines’ explosions and catastrophic collisions that have occurred in Earth’s orbit. Besides, 1.2 billion metal needles were put into orbit by the US Air Force in 1962 and 1963 to see if radar signals could be bounced off them. The collisions and explosions have unfortunately taken place at fairly high altitudes, which means that most of the leftover debris will stay in orbit instead of coming down and burning up in Earth’s atmosphere.

(Adapted from The Herald Tribune)

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Unit 6

Text 3. DESTRUCTIVE FORCE OF EARLY CIVILIZATIONS

The Anastazi Indians and other early civilizations may have killed themselves off by plundering local plants and animals.

New archaeological findings suggest that, far from living in perfect harmony with nature, prehistoric civilizations dealt major and sometimes fatal blows to their natural surroundings. Many investigators now question the notion that environmental problems began only with the Industrial Revolution in the 19th century.

To be human means you have the ability to modify your environment in a way other animals can’t. A Stone Age society can’t go in with bulldozers and chain saws (ланцюгова пила). Nevertheless, archaeological excavations (розкопки) prove that long before the appearance of industrial civilization, prehistoric societies were levelling forests, exterminating entire plant and animal species and exhausting farmland. The destruction they wrought sometimes destroyed them in turn. The mysterious disappearance of the Anastazi Indians may be an example. On the territory of the present-day New Mexico and Arizona, the Anastazi built an elaborate complex of roads, irrigation channels and, most notably, giant pueblos built of stone and masonry (кам’яна кладка), some five stories high with 800 rooms or more. All were abruptly abandoned around AD 1200. Until now, the majority of archaeologists have believed that the reason was a prolonged drought. But by using an electron microscope and carbon-14 dating, scientists analyzed the logs of pueblos and came to the conclusion that the Anastazi had systematically deforested the canyon until they had to travel 50 miles or more to gather wood for fuel and logs for building their dwellings.

Archaeologists have a tendency to interpret any change in the archaeological record as a climatic change. This so-called environmental-determinism theory, which holds that climate dictates culture, is being eroded by the new findings.

The people of Easter Island, known for their enormous stone statues, may have been another culture that reaped its own bitter harvest: the island was heavily wooded until Polynesians settled there around AD 400. By the 18th century, when Europeans first landed, it was treeless. Deforestation would have hastened soil erosion, lowering crop yields. It would have eliminated the source of the dugout canoes vital for fishing. Although European settlers hunted a number of birds to extinotion, they were merely finishing work begun by the Polynesians centuries before. 80 to 90 per cent of the species of birds in the South Pacific had been already gone by the time Captain Cook came in the 18th century. Species that weren’t hunted were wiped out when the Polynesians cleared the low-land forests for agriculture and destroyed their habitats. Some of these birds survive on a few remote islands, but others live on only in the legends of islanders. They have names for birds they’ve never seen. And archaeologists can find birds that match their descriptions exactly in the fossil record (зкам’янш пам’ятки минулого).

(Adapted from The US News & World Report)

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