Wednesday, July 7, 1999

Hurtful heights
By Dr S.K. Jindal
The ongoing conflict in the Kargil area has brought the health risks to soldiers at high, snow-capped peaks into sharp focus. It is often said that the high peaks engulf the troops.

The six billionth baby
By Dr Rachel Sarah
NEW YORK: As prospective parents worldwide are planning the "millennium baby", to be born as the world enters the next century on January 1, 2000, there's another momentous birthday round the corner — the day of the six billionth baby.

Life after nuclear war
By Dr K.C. Kanwar

A nuclear war portends annihilation of life from the planet earth. To develop public consciousness on the possible devastation it can cause is the need of the hour. Not only the teeming millions but even politicians and many military strategists are not fully aware of the terrible aftermath when the user is the loser and the survivor envies the dead. Never was this question more relevant than today when well over 10,000 megatonnes of nuclear arms are stockpiled. Nuclear technology, if it slips into the hands of terrorists (operating globally), may add new dimensions to nuclear adventurism. The scenario is scaring. Einstein once commented that it was "really unrealistic optimism to presume that some will survive the third (nuclear) war to fight the fourth one".

Wars have been killing people in thousands. Nuclear war fare will also precisely do the same. If so, what is so special about it which justifies global public clamouring against it? Yes, indeed, a nuclear war is different in many ways. Some known and some still unknown aspects have to be thought of. The exact simulation of a nuclear holocaust is not yet possible. Strictly speaking, even the scientific projections available to date are based upon the guesswork of scientists and may not be precise.

First, in a nuclear holocaust there is rapidity of destruction, widespread fires, intense nuclear fallout and severe cyclones around the hit-site. An unrestricted nuclear conflagration, unlike conventional warfare, can destroy the world in a few hours — well before any settlement to avoid it can be reached. Second, it has potentially long-term biological consequences which are far more severe and serious than those of conventional wars.

The most dreadful aspect of a nuclear war is immediate as well as delayed mutilation of germ plasm, threatening not only the existing life but even life in the future.

Further, radioactivity will not only kill all near the hit-site but also affect those placed distantly and subjected to sublethal doses of radioactivity. The distant survivors will suffer a variety of damages such as stunted growth, reduced fertility, impairment of the immune system, increased mutational tendency and a higher incidence of cancer and other diseases. These latent effects, by and large, will persist for a long time and affect not only those who survive the nuclear holocaust but also their progeny.

The atomic bomb is a highly explosive weapon which derives its energy from a nuclear (atomic) reaction rather than from a chemical reaction. A nuclear explosion can be produced by either splitting (fission) or joining (fusion) of atomic nuclei; explosions as a result of fission are called atomic explosions whereas those which originate because of fusion of atomic nuclei are termed hydrogen bombs. Nuclear energy is the energy released when the constituents of atomic nuclei are rearranged on a large scale. In this process the nuclei lose some mass which is converted into energy following Einstein's relation E=mc2 where E is energy, m is the mass converted and c is the speed of light. Such nuclear transformation is responsible for the energy output of atomic and hydrogen bombs — and of nuclear power reactors.

The major difference between atomic and conventional explosions is in the energy liberated per unit mass which is far greater in the former case. The energy released by fission reactions is greater than that available by chemical means; one small atom bomb containing a little more than two pounds of fusionable uranium can match many thousand pounds of chemical explosives. Fusion explosions are far more powerful than the fission ones.

A nuclear detonation releases vast quantities of energy in the form of sonic, thermal, radioactive and electromagnetic radiation. For a fission bomb, about 50 per cent of the energy is released through shock (sonic or blast) waves, 35 per cent through thermal radiation and the rest 15 per cent through radioactive radiation. For a hydrogen bomb, the corresponding values are 54.5 per cent 38 per cent and 7.5 per cent respectively.

The temperature reached in an atomic blast is unimaginably high. One third of the energy of the atomic blast is in the form of thermal radiation. The temperature generated by a nuclear explosion is tens of millions of degrees Centigrade — hotter than the interior of the sun. Even a one megaton air-burst can simultaneously ignite fires over a large area.

A five feet radius from the hit-site is subject to an unbelievable temperature approximating 3,000,000 degrees c, which will produce a "fire storm" of an unprecedented magnitude around the hit-site and ash life instantaneously. This will also makes gases and smoke rise high into the atmosphere with tremendous speed, thus sucking huge columns of surface air around the hig-site into a conflagration at a hurricane speed averaging 65-100 km per hour and sucking people into the inferno. The area of fatalities is much larger with the huge fires unprecedented in scale than with actual blast.

Nuclear detonation devices: Nuclear bombs are referred to by their energy yields in terms of the weight of the chemical explosive =2,4,6-trinitrotoluene (TNT) that will have the same energy yield. For example, one kg of TNT yields the energy of 4.615x106 joules. So, a nuclear detonation yielding this much energy will be referred to as a one kg detonation; one kilotonne (KT) and one megatonne (MT) detonations will yield 4.615x1012 and 4.615x1015 joules respectively. The Hiroshima bomb was of 13 KT and the Nagasaki bomb was of 21KT. Our first Pokhran underground explosive yielded an energy of 13KT. Today, the USA and Russia possess bombs of more than 50MT each or more. A nuclear explosion is called an air blast when it occurs within the lower atmosphere but at sufficiently high altitudes so that its fire-ball does not reach the ground.

Environmental consequences: In an all-out nuclear war, approximating=3,000 MT ground blasts, 80 million tonnes of submicroscopic particles are estimated to be ejected into the stratosphere, forming dust clouds preventing visible light from penetrating and so a darkened atmosphere is created. The average particle size in the dust can be less than 10 micrometres — less than the average infrared (IR) wave-length, implying that IR can penetrate the cloud but visible light cannot and so there is darkness akin to night during the day. These dusty clouds, which also carry nuclear activity, will not immediately settle down but hang around for quite some time before these are naturally dissipated. The rotation of the earth distributes this nuclear fallout much more widely than anticipated or even scientifically guessed because the earth is moving with respect to the atmosphere, which is stationary. This is why any nuclear explosion, irrespective of its location and magnitude, is bound to be of international concern. The rotation of the earth distributes the nuclear fallout much more widely than anticipated. An atmospheric nuclear blast by nations in their own territories, therefore, can no longer be considered their internal affair; these will affect life indiscriminately — much beyond the site of the occurrence and the territorial limits of the testing country and hence this warrants international condemnation and concern. There is only one biosphere for us all to share. Has any single country the right to contaminate it?

Following nuclear explosions, in addition to the sprinkling of radioactive dust far and wide, huge amounts of smoke and burnt ash will be carried high into atmosphere which will change the climate akin to volcanic explosions which, in turn, result in freezing temperatures — the portent what the scientists call Nuclear Winter (NW) resulting in an unprecedented climatic disaster the severity of which will be directly proportionate to the number and magnitude of nuclear explosions or the total nuclear fuel consumed.

The Nuclear Winter theory postulates the spreading of huge clouds of smoke from the bombed targets. Such clouds will darken the atmosphere; sunrays will not reach the surface of the earth. The day after the explosion will be cold, dark and immensely radioactive and such conditions may persist for days, weeks or even months. It is predicted that little, if any, sunlight will penetrate the radioactive clouds and reach the earth. Vast areas will be plunged into darkness impairing, even completely halting, photosynthesis with its concomitant manifestations — immediate or delayed.

The ability of the atmosphere to act as a window for sunlight and as a blanket for heat serves to create the greenhouse effect. CO2 lets sunlight pass through it but absorbs IR and provides warmth to the lower atmosphere including the earth's surface. Because of the Greenhouse Effect and the consequent heating up of the atmosphere, the temperature gradient builds up in the atmosphere, with the temperature decreasing with height which causes a wind draught and air movement. If opaque particles such as dust particles are suspended in the atmosphere as after nuclear blasts, sunlight will be absorbed at a higher altitudes. The earth will receive very little sunlight, causing an Antigreenhouse Effect. This will result in the cooling of the earth.

Without the Greenhouse Effect now, the temperature may not vary with height and the lack of wind draught may cause a stagnant atmosphere. It is estimated that in an all-out nuclear war, an unimaginable amount of smoke will be generated. Such smoke, comprising essentially of sooty particles, will absorb about 80% of the sunlight reaching the surface.

The CO2 generated due to combustion will absorb the IR or heat radiation before it reaches the surface. Consequently, the earth's surface will be subjected to prolonged darkness and noon light will not be brighter than moonlight.

It is further estimated that in such an eventuality, according to Turco and his colleagues, the earth's surface temperature will fall by 40o c — i.e the average temperature will hover around 25o c; the portent of a Nuclear Winter is associated with a nuclear war. The UV radiation emitted by the sun is normally filtered out by the ozone (O3) layer in the upper atmosphere. A nuclear blast produces several oxides of N2 which catalytically degrade ozone letting UV-rays come to the ground unimpilged. This will have a devastating effect on the biosphere. A major nuclear war involving many nuclear explosions in the atmosphere will produce a prolonged and widespread Nuclear Winter which will lead to the extinction of several species — both of plants and animals.

In a closed ecosystem, the survival of one species depends on others and, therefore, the extinction of one leads to the extinction of others. A nuclear holocaust will create tremendous physical and mental stress for the survivors. NW raises the question of the very survival of the human race. It is impossible to visualise environmental degradation in totality following a nuclear holocaust. The nuclear assault on the geomass will mean denudation, causing soil erosion and other accompanying problems. The radioactive fallout will contaminate the hydrological regime (surface and ground water). The recovery from these will require several decades.

If a one-megatonne nuclear bomb is exploded as a surface blast, the estimated damage, according to Dr (Col) S.K. Sharma, Deputy Director, Institute of Nuclear Medicine, New Delhi, will be as follows:

After the explosion, a 1.6km-wide flashing and sizzling heat wave will be set out in the countryside. The temperature within 1 km diameter will approximate 10 million degrees C where people and vegetation will be ashed instantaneously. Following this, there will occur violent winds and rapid changes in air pressure which will smash buildings. Deadly radiation will hit the ground 2.5 km away from the hit-site. Steel, stone, granite and glass all will melt like butter. Plastic, wood and fabrics will spontaneously start burning even 6.5-8 km away. Those 11 km away, and exposed directly, will suffer third-degree burns with 100% fatality. People, 16 km away from the site of the explosion, will receive first degree burns.

After the explosion and following the heat flash, fire will spring up all over. Wooden structures, gas stations, petrol pumps and dumps will explode and burst into violent fires.

Everything will be levelled in a circle 4km out from the hit-site. About 6.4 km away, houses will be smashed to bits. Buildings will be damaged beyond repair even 9 km away. Doors will be blown off from the buildings 25 km away.

According to this very estimate, if a bomb of this magnitude hits Delhi, 50% of the population will be in the immediate zone of death. Two million people living within a radius of 2.4 km from the hit-site will be ashed out. Over a million in the next deadly zone will be sucked into the bomb inferno. For a place like Delhi, 2.5 million survivors will die in a few weeks after the explosion for want of hospitals, which will have been destroyed or rendered non-functional. For the rest of the survivors, the medical resources of the nation will not suffice.

Besides, explosion on the ground will throw up tonnes of earth into the air forming a radioactive cloud 8-13 km wide and 50 km long in size which will emit about 3000 REM of radiation. Even about 150 km away, the fallout levels will be about 900 REMS or twice the deadly level. It will take about 10 years for an area exposed to 3000 REMto return to peace-time safety standards.

Shock waves from a small 0.5 MT nuclear air blast can destroy reinforced concrete structures within a radius of about 5 km from the point of detonation. The wind speed at a distance of 1 km reaches more than 1200 km per hour — i.e 10 times more than a devastating cyclone. Asimilar explosion on the ground (surface blast) will form a crater 250 metres is diameter and 75 metres deep, displacing a total mass of 8000 million tonnes; it can also throw a two-tonne boulder to a height of more than 1 km.

Prof Kanwar is the former Chairman of the Biophysics Department, Panjab University, Chandigarh.

Hurtful heights
By Dr S.K. Jindal

The ongoing conflict in the Kargil area has brought the health risks to soldiers at high, snow-capped peaks into sharp focus. It is often said that the high peaks engulf the troops. They not only do so but also bite them and inflict much morbidity from a variety of medico-surgical problems. The peaks are most beautiful to look at and strategic in position for the Army, but these are dangerous to live on. They cannot be avoided. That is why they are important.

Cold injury is, perhaps, the most commonly known and widely appreciated health risk posed by subzero temperatures. Chill blains and frostbites cause loss of tips of fingers and toes whenever there is a prolonged and persistent exposure to cold. Such accidents occur in spite of precautions taken to avoid exposure. This is especially so when one faces the enemy and takes surprise action apprehending an attack. Many precautions are lost sight of in such situations.

Fatigue, exhaustion, dehydration and cramps are common in the hostile surroundings requiring long walks and ascents in a difficult terrain, sometimes with little availability of food and water. These are the problems faced by the soldiers not only on hills but also in forests and deserts. That is the sad part of life of an armyman. But the problems are much more complicated and complex on the heights. Added to this is the bright sunlight reflected from the vast icy surfaces. Visual problems, including blindness, may occur if proper sun-goggles have not been used.

The atmospheric air on the hills is fortunately pollution-free, but thinner in its contents. The amount of oxygen in the air and, therefore, its pressure decrease as we go above sea level. It is bearable up to about 10,000 feet, beyond which trouble is likely to occur. Mountain-sickness, including fatal pulmonary and cerebral oedema, is a well-recognised complication.

Mountain-sickness is a wider term which encompasses different neurological, pulmonary and cardiac manifestations. It happens generally after an acute ascent, especially in the case of a new recruit. Headache, tinnitis, ataxia and vomiting may occur within the first few hours of arrival. Chest congestion, breathlessness and severe oxygen deficiency ensure from pulmonary oedema when the lungs get full of water. Altered consciousness and coma may follow if corrective steps are not taken. The management of high-altitude pulmonary and cerebral oedema requires immediate descent to a lower height. Drug treatment serves no useful purpose. Supplemental oxygen administration may temporarily help until evacuation. This does not reverse the ongoing formation of fluid in the lungs, the mechanism of which is not entirely clear.

It may be interesting to cite the example of an occasional mountaineer climbing the Everest without using additional oxygen. Even more puzzling had been the case of two stowaway brothers who had hidden themselves in the undercarriage of a British Airways Dhaka-Delhi-London flight in October, 1996. One of the two was recovered alive at the Heathrow Airport in a semi-conscious state; the other brother fell off when the undercarriage opened minutes before the landing. Survival in this case could possibly be attributed to an almost frozen state due to extremely low temperature minimising the oxygen needs of the body. Such examples are,. however, rare and remain mysterious. They cannot take us away from the fact that additional oxygen is important whenever one goes beyond an altitude of about 16000 feet.

A peculiar sub-acute complication of cardiomegaly and heart failure was recognised amongst soldiers serving at the Siachen glacier after a stay of a few weeks. Complete recovery took place after a few days' sojourn at Chandigarh.

Prevention, acclimatisation and avoidance of prolonged exposure are the three principles important in the overall management of the condition. Undoubtedly, the Indian Army is quite conscious of these problems and its medical wing is trained to treat them. The soldiers are suitably acclimatised to live on those heights.

Problems occur when a massive influx is required and ground troops are lifted in a hurry to reinforce the existing strength. Arrangements in such a situation are likely to go haywire. It is this area which needs urgent medical attention and poses a challenge to the clinician and the research scientist alike.

Dr Jindal is Additional Professor and Head of the Department of Pulmonary Medicine, PGI, Chandigarh.

The six billionth baby
By Dr Rachel Sarah

NEW YORK: As prospective parents worldwide are planning the "millennium baby", to be born as the world enters the next century on January 1, 2000, there's another momentous birthday round the corner — the day of the six billionth baby.

The "Day of Six Billion" is still seven months away but Joke van Kampen, the media director of the World Population Foundation in the Netherlands finds herself fielding calls from reporters who want to know where the six billionth baby will be born.

"There's no such thing as the six billionth baby," van Kampen responds to callers; "the six billionth baby was born thousands of years ago."

The US Census Bureau has declared October 12 as the official day when the earth's population will reach six billion. Reporters, politicians and community leaders have already jumped on the six-billion-day bandwagon, but the occasion seems to be causing some confusion.

"Originally, it was thought that the day would be in June this year, but then it was changed to October," said Kathy Bonk, executive director of the Communications Consortium Media Centre (CCMC) in Washington, DC, during a workshop about the big day at the recent meeting of the UN Commission on Population and Development. This session was in preparation for the special session of the UN in June this year, to review and appraise the implementation of the programme of action adopted at the 1994 International Conference on Population and Development (ICPD) in Cairo.

Never mind the fact that July 11 is World Population Day. And an official world population report is due for release on September 22 this year.

"There seem to be lots of population clocks out there," added Bonk. In 1804, the world population reached one billion. In 1960, it was three billion. This means that the world's population will have doubled within four decades.

The ICPD called on governments to increase spending on population and related programmes to $17 billion per year by 2000. The figure, about 10 days' global spending on armaments, climbs to $22 billion by 2015.

"I think we're going to get a lot of six billion babies," joked Alex Marshall, who heads the UNFPA media team. "It's a sexy idea." "But it's not just about babies,"Marshall added seriously. "It's also about the fact that people are not dying, too." — WFS