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Scientific VIEW

Radon Threat Dangerous but Blameless

December 03, 1986|BETTYANN KEVLES

Looking for a new home? Time was when termites were the only threat that had to be checked out. Now, however, lenders in different parts of the country are insisting that buyers ascertain seismic safety as well as the possibility of environmental pollutants.

Spills, leaks, seepage and general human sloppiness account for too much of what makes contemporary life unsafe. It almost comes as a relief to deal with an environmental threat that isn't anybody's fault. Not only are there no villains in this situation, but here is a pollutant that, once identified, can usually be eliminated without having to bankrupt an industry or oblige thousands of people to decide between their health and their livelihood.

The new enemy is radon. It is a colorless, odorless, inert, radioactive gas that may be responsible for as many as 20,000 cases of lung cancer a year.

Environmentalists used to associate radon pollution with houses that had been built with the wastes from uranium mines in Colorado and Utah. Then, in 1984, an engineer working on the construction of a nuclear power plant in Potsdam, Pa., set off the plant's radioactivity alarms. A little detective work traced the source of his radioactivity to the engineer's home. Since then investigators have discovered that a large area in Pennsylvania, New Jersey and New York, called the Reading Prong, is a geologic formation that emits large quantities of natural radioactive gas. This past September a physician in Philadelphia moved into an elegant house on the city's prestigious Main Line and, in the process of having his home screened for contaminants like formaldehyde or asbestos, he discovered radon levels that made breathing in the house equivalent to smoking 55 cigarettes a day. He is suing the contractor who installed the ventilation system. Hence the recommendation by Pennsylvania realtors that radon tests be included routinely in housing inspections.

Radon is a paradox. It is, in part, the price we are unwittingly paying for sound construction. It is likely that human beings have been exposed to radon for generations with no ill effects. However, pressure from the recent energy crisis encouraged builders to concentrate on sound, airtight insulation. Radioactivity has always existed in nature, but in the past radon gas simply drifted out the windows and through the crannies. Now some of the people living in climate-controlled houses are exposed to a build-up of radon.

Radon itself is harmless, but two of its progenies are isotopes of polonium, which trigger the release of alpha particles in the tissue of the lungs. This tiny amount of radioactive material, added to the other sources of radioactivity that surround us, can trigger the onset of cancer.

Human beings can absorb a good deal of radioactivity safely. A 1982 report of a U.N. scientific committee on the evaluation of radioactivity presented a picture of a "radiation pie," all the sources of radiation to which we are exposed. This includes radioactivity from gamma rays and cosmic rays as well as from medical sources such as dental and chest X-rays. But 40% of the pie comes from radon. Radon plays a far larger role in our lives than all of the radioactivity we absorb from foods exposed to radiation (such as fallout from Chernobyl) or from riding in an airplane.

When radon pollutes a house it usually enters from below, as the differential air pressure inside and outside the house draws the gas by suction up from the soil. In places like Berkeley (where a study of the national distribution of radon has just been published by a team at the Lawrence Berkeley Laboratory), a clay-like substance in the soil seems to prevent radon from sifting through. Areas with porous soil, like that in Pennsylvania, have a greater radon problem.

Like radioactive fallout, radon is an invisible enemy. Until the alarms went off in the Pennsylvania nuclear power plant, we were generally unaware that it was polluting so many homes. It is probably unnecessary for homeowners in Southern California to invest in radon inspections because so far there has been no evidence of the gas here. It might not be a bad idea to include radon tests along with other environmental studies when new subdivisions are proposed.

Radon, or the threat of radon, attracted the attention of the marketplace. Radon inspection and radon control are already growing businesses. Detection is done with a variety of gadgets either instantly, or for more secure results, over a period of time. It costs between $150 and $2,000 to install a suction-blower system that will reduce the amount of radon to an acceptable level.

Radon is a real danger, but it is neither an environmental scandal nor an insidious epidemic. It is a poison that can be easily detected now that we know enough to look for it. Once detected, the solution is a matter of pipes and pumps. Radon is a carcinogen against which we can protect ourselves without having to worry about what we put in our mouths. In no way benign, it is not overwhelming.

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