What It Means To The Scientistis

[?]mic Fallout

And What It Means To You

By Wayne Denbigh

Five years ago, in October, 1952, the United States of America sploded in the Pacific the first Hydrogen Bomb ever conceived and lanufactured by man. The scene was the Marshall Islands; the site, niwetok Atoll, from which the 150 inhabitants had been removed reviously and resettled on Ujelang, to the south-west.

r later periods, two other H bombs were also exploded. All three went off “according to idule” —with the exception of little-publicised “Rongelap hi nt.” iveral hours after the largest H b had mushroomed, in March, , a top-secret radio message i the US flagship headquarters a destroyer racing 100 miles wards for the necklace-string islets comprising Rongelap. lily, the 64 bewildered natives i hustled aboard the warship whisked away. An unexpected ige of wind had carried the i-active cloud towards the sup ply safe island. icky white particles had already in to fall on Rongelap. Re

sembling snow, they actually were bomb-pulverised coral charged with radio-activity from the nuclear fission. This was atomic fallout!

Rongelap’s people, the scientists

from the rescue ship found, had been exposed to 175 roentgens of radiation. If they had remained at the atoll a few hours longer, most would have died, for the fatal dose, on an average, is 400 roentgens.

Fortunately, all the Islanders, both young and old, recovered.

The fallout on Rongelap was one of the three types liable to occur after atomic explosions, according to material recently released by the US National Academy of Sciences, which had been making an ex tensive and intensive study of the subject.

Type one, described above, occurs anything up to 250 miles down wind from the explosion; it is the visible kind—concentrated coarse particles that settle to earth within a few hours and emit gamma rays that penetrate the unprotected body.

These are the rays that scientists fear could cause marked changes m individuals’ genes, the seeds of heredity, leading to cripples and other defectives in future genera tions. Experts stress that the absolute limit for this type of fall out is less than 250 miles from the explosion. „ Since there will be no native population or unprotected Europeans within a 250-miles radius of Malden Island (near which one of Britain s crack Valiant bombers will drpP her first H-bomb) the official attitude that there is no real danger from fallout during the forthcoming Christmas Island area tests con forms to the known scientific facts. • THE second type of fallout is an invisible kind. Its microscopic particles are coated with radio active fission products and are wind borne in the troposphere (the layer of the atmosphere mainly respon sible for the earth’s weather) for weeks and even months. The particles reach earth mingled with rain and/or snow, but by that time most of their radio-activity has ceased.

This fallout is mostly distant; that is, it may occur thousands and thousands of miles away from the point where the actual explosion took place.

There is a certain amount of gamma radiation when this fallout settles on the ground, but this type

affects humans only mildly—it is not one-fortieth of the natural radio activity that the average person is likely to be exposed to during the next 30 years from sources such as cosmic rays and radium and thorium in the earth.

THE third type of fallout is the most insidious. H-bombs blow

about half of their radio-aE particles into the stratosg (above 55,000 ft), where they ree for a matter of years, by w time the principal gamma emitters (Cesium 137, for insta have become harmless —but om gredient still remains radio-ao Strontium-90.

* Penrhyn, inhabited, is only 350 miles from Malden.

Articles of Strontium-90 eventu r descend to the troposphere and ie down to earth finally in rain snow, all over the world, ostead of the penetrating gamma s, Strontium-90 emits only short ge beta rays, with negligible ct on the human body. When it ches earth, Strontium-90 is scat id far too thinly for the naked to see, of course, ut, as the National Academy of ;nces experts have pointed out, drawing minerals from the soil, its absorb Strontium-90 and it ses to humans by way of vege les and dairy products (par larly milk and cheese), as a re of cattle feeding on Strontium mpregnated fodder, tie permanent danger is that pitium-90 resembles calcium and aken up by the bone structure the body, and thus becomes a aitial cause of bone cancer and jemia (blood cancer). dentists say that the quantity de -5d so far in human beings is nless, but the salient point is f even to-day a measurable unt of Strontium-90 has been id in some children’s bodies, irently from contaminated coWs’

This, even though it is nated that only one-quarter of Strontium-90 from past atomic i in the Pacific, USA (Nevada), Russia has settled on earth so The remainder of this bomb still is floating around in the 3’s upper storey. actly what is Strontium-90, the an may well ask? Named for atian, in Argyll, west of Scot , the place where the element ibol: Sr.) was first discovered, i white-silverish in its metal , Strontianite. The H-bomb cles are in the form of radio b Strontian Carbonate; ordinary itian Carbonate is a whiteish ler which is in limited use, ?h its cousin compound, itian Nitrate, is well known—it the red glare in fireworks and ,1-fares. lot her compound, Strontium lite, has been used medically as .Iterative in the treatment of ria and for tropical skin ses. mally, Strontium compounds ot radio-active nor particularly but Stronium-90 (the H-bomb retains its radio-activity for :ceptionally long period. Some have shown, for example, that after 25 years it has retained than half its original radio ; strength. Eventually, how it turns into non-radio-active liurn (from which zircons are !). t how much Strontium-90 the ■n body can absorb is still the Jt of much debate among lists, but an official of the ic Energy Commission in New , has put the “permissible at one-tenmillionth of a curie iio-active Strontium (a “curie”

being the unit of measurement of a radio-active substance).

The same scource has calculated that, taking into account the number of A- and H-bomb tests held since 1950 and the hypothetical number of probable tests in the next decade, the maximum possible amount of Strontium-90 in a human’s bones would at the end of that period be qnly 25 per cent, of the allowable limit.

But there are too many “ifs” and

uncertain factors in the calculation to place too high a reliance on this figure. One thing is certain, though: that the safety margin at present still is wide. Nonetheless, a grim question mark hovers over the answer as to how quickly this margin would shrink if H-bomb tests were accelerated?

The warnings have not gone un heeded. Now, nearly 90 monitoring stations have been set up around the world by the Atomic Energy Com

sion, its British counterpart and jciated bodies in other countries tside the Iron Curtain) to check ; tabulate the result of atomic jut in rain and snow from week week. The reports go to :ral bureaus in USA and Britain, en of the scientific world are ling on the United :ons Disarmament Committee that this august body will suc in the restriction of the number ,tomic bombs that can be test -1 in any given year. This, they ; would keep the Strontium-90 jer factor under control. ►wever, the men-in-the-street on-the-plantations and in-the ids-stores), with a jaundiced and a sickly grin, recalls how ective the League of Nations rmament Committee proved to m decades ago. He can only 5, even if reluctantly, with the ern Powers’ viewpoint that the are necessary and that the lT> g Allied stockpile of atomic ons is the best deterrent to any Powers starting all-out nuclear ire.

Dsphate shipments from Nauru Ocean Islands last year at 353 tons were a record, accord o the British Phosphate Com- Dners. Of the total, 1,081,842 went to Australia, 587,361 tons ew Zealand and 102,150 tons itain. The total tonnage de d to Australia and New Zea-

land was the largest distributed by the commissioners in these two countries in any one year. t Five United States Naval vessels called at Suva, Fiji, on April 29-30.

There was a total of 124 officers and 1,974 ratings on the vessels.

LADIES ON LEAVE: Left to right, Mrs. B.

Haydon, of Wau, New Guinea, who went to Australia recently on leave. (Mrs. Haydon's son was killed some years ago in an aircraft accident in NG; she entered one of his colour photos in the RIM Quarter Century Competition where it won a prize). Mrs. R. Zuydam, wife of well-known Qantas pilot, Rinus Zuydam, returned to Lae in April after six weeks holi day in Japan. Mrs. J. Lloyd, wife of Qantas chief traffic-officer, Port Moresby, who spent Easter in Lae. And Mrs. O. M. Pittendrigh, her mother-in-law, who has spent five months in Port Moresby.