WHERE NATURE IS DEADLY

Press, Volume CXIV, Issue 33514, 20 April 1974, Page 11

WHERE NATURE IS DEADLY

(By

JOSEPH MARSHALL)

It is 25 years now since the peaceful Pacific islands of Bikini and Eniwetok were shaken by an explosion more lethal, more violent, than anything the world had ever known.

The United States triggered off the first H-bomb test there, turning the coral waters into a radioactive wilderness and scooping huge craters where lush vegetation once grew. Now the islands appear to have reverted to their previous state. But in fact things are not the same — and never will be. Many of the birds and fish which abound on the islands are full of deadly radiation, and their consumption is strictly forbidden. Rain has washed the radio-active poisons from the surface of the earth and many of the islanders have returned to homes which seem much the same as when they left — but in many ways they have been radically changed. The shape of Bikini atoll is the same, except for one or two new lagoons so perfectly rounded that their origins could only come from the fearsome heart of nuclear explosions, rather than the gentler architecture of nature. Palms disappeared The coral reefs are still there, but most of the coconut palms that gave the island so much of its beauty have disappeared. •Yet many of the species of animals and vegetation that were wiped out in the heat of the nuclear blasts have reappeared in such profusion that the islanders — with help from American

scientists — are having to control their numbers. “One of the most numerous species — and the one which first returned in strength to recolonise the island — is the coconut crab,” one islander recently reported. “These once formed part of our staple diet. “Today, the crabs crawl in their, thousands over beaches that carry their own deadly payload of Strontium 90, the radioactive by-product of the atomic tests.” This long-term radiation passes from vegetation to the bone structure of mammals and to birds’ eggs. It has built up to an alarming degree in the crabs’ shells and today their consumption is strictly forbidden. Different reactions • Not every species reacted the same way to the massive doses of radiation released into the earth, air and atmosphere, during the nuclear tests. On Eniwetok American scientists found a colony of Polynesian rats alive and apparently thriving in the apocalyptic wilderness following one H-bomb test. The rats had absorbed a radiation dose of 6000 roentgens — 10 times the amount it takes to kill a man — apparently without suffering any lasting ill effects.

Insects and spiders absorbed doses of up to 60.000 roentgens — far more radiation than it takes to wipe out every other kind of living creature. Varying degrees of resistance were found in plants, too. Those which flourish in strong sunlight — and emit a degree of radiation in their own right — absorbed far greater

doses, with no adverse effect, than forest plants. Another interesting fact to emerge from the analysis of the aftermath of the Bikini and Eniwetok tests was that some animals appear to have their own built-in "geiger counters.” This was particularly true of the islands’ bird population: most species refused to build their nests with mud taken from radio-

active areas. It was as though they knew that if their nests were contaminated their eggs might become contaminated too. Whole generations of giant turtles were wiped out when their contaminated eggs refused to hatch in the wake of the explosions. Actual mutations appear to have been confined to plants growing near the explosions. There is no evidence so far that

mutations exist among the animal population, although it is possible that some may manifest themselves generations from now. Whatever happens in the future, the scientists who paved the ■ way for the return of the human inhabitants of Bikini have been astonished by the tremendous • resilience of nature and its ability to reconquer the devastated wasteland in such a relatively short time.