letters

Radon's Link to Lung Cancer

To the Editor:

Charles H. Atwood's article, "How Much Radon Is Too Much?" [J. Chem. Educ. 1992, 69, 351 I, is an excellent summarv of the radon literature. However. it does not ~ ~ ~~ ~~~~ <

cover one major area: What is known of actual lung cancer deaths in nonsmokers and the radon levels in their homes? ~~~~ ~

A study on this question was stopped due to a lack of funds (I).

The effects of radon have happened in the past, are hap- pening now, and will happen in the future. Therefore, we can evaluate the deaths from lung cancer today and not have to wait 20 years.

Estimates of lung cancer deaths in the US. due to radon are 20,000 per year per EPA(2). This would account for all the lung cancer deaths except for smoking which causes 120,000 deaths per year. How do you account for the many other causes of lung cancer? Consider for example: asbes- tos, secondary smoke, diesel particulates, black lung, sili- cosis, nuclear plant exposures, ionization radiation, indus- trial chemicals, smog, etc. (3-5). These would account for many of the deaths now estimated to be only due to radon.

Philip Handler, past president of the National Academy of Science, said that "less than 1% of all cancers is the re- sult of our unavoidable exposure to background radiation" and "the body is, in point of fact, remarkably resistive to carcinogenesis due to radiation" (6).

If people living in homes of "200 pCin are receiving an- nual exposures that are essentially equivalent to those re- ceived by people evacuated from the vicinityof Chernobyl" (71, why haven't we seen a high incidence of radiation sick- ness, especially in children, in Pennsylvania? Many resi- dents have been exposed to this level for a lifetime.

The Watras family was exposed to 4400 pCin of radon in their basement (8). This is equivalent to approximately 602 X-raysper day by EPAestimates. (4 pCi/Lis compara- ble to 200 X-rays per year) (9). The EPA responded to my inquiry by saying that the Watras family only had "a much higher risk of contracting lung cancer later in life" (2).

They certainly are not particularly susceptible to radiation sickness.

J. A. Johnson put this problem in perspective. He states that "Legal ramifications of selling a home that later tests for a radon level higher than EPA recommendation (4 pCin) can only be contemplated with gloom. All this in the face of evidence that the only strong correlation between radon levels and lung cancer are found with cigarette smokers and epidemiologic studies that show reduced lung cancer rates in countries with high average indoor randon levels" (10).

Incidentally, I have one report of radon levels increasing from 2 pCiL to 200 pCiiL after a heavy rain (11). This helps confirm the literature that atmospheric conditions cause great variations in readings (12-14).

Radon-caused lung cancer estimates, based on variable measurement techniques and unproven mathematical cor- relations, appear to differ from the total number of current lung cancer deaths. Further studies are needed before ad- ditional regulatory legislation is passed due to fear of ra- diation.

Literature Cited: 1. Bamhardt, J., Pennsylvania Department Environmental Resaurcea, personal mm-

munieation. February 27.1992. 2. Guimond, R. J.. Assistant Surgeon h e r d , USPHS, Dimk.r, Office of Radiation

Pmmama. EPA. wrsonel mmmunieetion. Doeember 14.1990. 3. ~ b e l s k , P H., ~e;dnm. 1890,250,4979. 4. Luckenbaugh, R. W, Chem. Eng News, 1991 IAug. 19). 5. 5. Abeieon, P M.,Scienrm. 1891,254, 177. 6. Handler. P. Resented at Northwestern Univsraitv Cancer Center's DedicstianCere.

.. . -.., , ...-, . -, -- . - . 7. Atwood, C. H. J Chem. Educ, 19% 69,361. 6. Philadelphia Electric Ca. Measurement of the Wahas Home. 14400 pCi5 in cellar,

3200 pCi5 in lin~gmm, and 18W pCinin bpdmama.) 9, A Citizen's Owide to &don: 1966; United States Eovironmemtal Pmt&ion ABmn

WTlce of Air and Radiation. U. S. Depsnmcnt of Health and Human Salvieaa. Centers for Disease Control. U. S. Government Pnntinc Ofice: Waehindn. DE. 1986: OPA-86-W4.

10. Johnson. J. A C h m . Em. News: 1890. IOd. 29). andreferene J. N~t i i i i l CCCCC . . rn.ri& im,sz, 102i

11. Averbaeh, Vietor, peraonalmmmunieatian,August20,1991. 12. Sprague. E. K, Chm.Eng.News,lW9,lApr. 171. 13. Welch, M. J., Cham Eng. N u & 1989, (%I 13). 3. 14. Nazaroff, a. si.,Alm. Envimn. 108419, 31.

Raymond W. Luckenbaugh 7 West Broadway

Geiiysburg, Pennsylvania 17325

902 Journal of Chemical Education

To the Editor:

I would agree with Mr. Luckenbaugh that my paper, "How Much Radon Is Too Much?", does not cover the sub- ject of smokers and nonsmokers and their interactions with radon. At the time I wrote the paper, there was no information about this subject in the literature, and I could not address that issue. I have completed another literature search and found that there is stiil precious little informa- tion on this subject, but a t least there is some. The most recent Morbidity and Mortality Weekly Report on Lung Cancer chronicled the 1986 deaths from lung cancer in the United States ( I ) . That year 126,000 people died from lung cancer and more than 80% of these deaths are associated with cigarette smoking. Passive smoking was associated with 3800 of these deaths, and asbestos exposure ac- counted for another 5500. The report estimates that the risk associated with radon and smoking is 6-11 times higher for smokers than nonsmokers. There is also a pre- liminary estimate that out of the 126,000 deaths, home ra- don exposure contributes 5,000-20,000 deaths. The report notes, "an estimated 85% of these deaths are due to the combined exposure of radon and cigarette smoke."

Furthermore, a t the 1991 annual meeting of the Health Physics Society, R. H. Johnson and E. Geiger reported that cigarette smoke increased the concentration of radon prog- env in the air of basements and mound level livine areas (2; After Lighting a single cigareke in the basement of a nonsmoking fam~ly's basement, the radon daughter levels went up 25% in five hours. A second cigarette lighting, 24 hours later, caused the levels to jump an additional 40%. Twenty cigarettes gradually lit over a 24-hr period, caused the dauehters' levels to double in three hours and triple in 28 houri. Apparently, the fine particulate matter in-ciga- rette smoke allows the daughters to remain suspended in air rather than depositing on the walls, furniture, or drap- ery Suspended in air, the radon daughters are much more likely to be inhaled and increase the exposure of the room's occupants. Apparently, the effects of radon and smoking are synergistic and substantially increase the risk of con- tracting lung cancer.

~ h v i o u s l ~ , if 100,800 deaths 1804 of 126,000) are added to the 3800 passive smokinn deaths: 5500 ashestos related deaths; and'20,000 radon related deaths, the numbers ex- ceed 126,000. However, there is considerable uncertainty in the radon estimate. Note that i t was reported as an es- timated 5,000-20,000 deaths, showing the uncertainty in the total population exposure and the dose response a t the levels found in homes. If radon related deaths are actually 5.000. then there are still another 5.000 deaths left to be attributed to black lung, silicosis, and so forth. The single most important issue that can be perceived from the mor- bidity and mortality data is that if radon levels in homes across the US. were dropped to 4 pCfi , the health effect would still be minuscule compared to stopping smoking.

While it is true that people living in homes with 200 pCiL Rn concentrations are receiving exposures equiva- lent to the people evacuated from the Chernobyl vicinity, i t is also not surprising that this is not immediately reflected in their demise. There are the issues of how the dose is delivered, and what organs of the body are effected. Expo- sure near Chernobyl was through airborne particulate and gaseous material, much of which was in the metallic state. (Many of the Chernobyl plant workers noted a strong me- tallic taste shortly before experiencing the symptoms of ra- diation syndrome.) Some of the metals are soluble in body fluids and then are precipitated in blood-producing organs and so forth that are much more radiation sensitive than lung tissue. Furthermore the Ukrainians received their dose in the relatively short span of a few days. Comparing this exposure directly to that of homeowners is fraught

with numerous difficulties. In the paper I did not intend to show an exact correspondence between these exposures but rather to give an idea of the size of the doses involved in home Rn exposure.

The highest radiation exposure for the Watras family that I am aware of is 2700 pCiiL which is still quite large. Using the EPA's estimates fromA Citizenk Guide To Radon that corres~onds to 370 chest X-rays per day (3). I susoect that the E~;A has overestimated the risk in ;his instance. I note that anlong other assumptions, the KPA has assumed the house is occupied 75'"rf the time which is prohahly an overestimation. We should also note thnt human belngs can he exposed to large doses of radiation and still live long lives. Marie Curie must have received a radiation exposure in her earlv 30's thnt would rival or exceed the Watras' ex- posure. ~ h k died in 1934 at the age of 67.

I totally agree that the radon levels in houses are greatly affected by rain. Apparently as the water fills up the maces between the mains of sand and dirt. the radon is firced out into the at&osphere. An excellent'correlation of radon levels and rainfall is eiven in reference (4). -

As our knowledge of the average radon exposure in homes and its effects on the occupants increases, I feel cer- tain that the estimated risk from radon will decrease. As chemists we are aware that the EPA has associated some risk with chemicals, such as acetone and benzene, that we routinelv use in our work. I do not expect laboratories to cease using these chemicals because there is a risk associ- ated with them. However. the knowledne of the risk allows the labs to use these chemicals in asafer fashion. The same can be said about home radon exposure. The knowl- edge of the risk, which I hope my paper presented forth- rightly, gives the readers a chanceto assess their own par- ticular situations and act accordingly.

Literature Cited 1. J. h e r Med. Assoe. 1989.262191.117&1172 2. R ~ I O ~ , J. sei. N#WS 1991. i40,79.' 3. A Citum'a Guide lb Rodon: 1986; United States En+mnrnental Rotedim Agency

Officeoffir and Rad,stion. U.S. Department of Health sndHvrnan Services. Cen- fen for Dinease Contmi. U.S. Government PRntlng Office: Washington, DC,l986: OPA.RE.nnd -"

4.Radonond asDemy Pmducfs in IndmrAicNazaroff, W. W.; Nem. A. V. Eds.: Wiley: New York, 1988.

Charles H. Awood Mercer University

1400 Coleman Avenue Macon, Georgia 31207

Soda Water, Supercooling or Freezing Point Depression?

To the Editor:

Soda water contains water, carbon dioxide, and trace amounts of sodium bicarbonate (maybe a ppm fluoride) and nothing else! The concentration of COP will vary slightly from bottle to bottle'but should never exceed 0.17 m (5 atm COz pressure) at 25 "C. The Henry's Law con- stant is 0.0345 mol COz per kg Hz0 a t 25 "C, which means

'A 0.1 m solution of C0, is only 0.2% dissociated (Ka=4.5 x lo-' at 25 "C) which means that 99.8% of the C02 remains as molecular C02(aq). However the 0.2% dissociation is sufficient to give the solu- tion a OH of about 3.7. Commercial soda is made bv dissolvina. under pressure.one to fwe voLmes of CO, gas per vo ;me of waier The pressure in tne oonles sno-Id never exreea 5 atm even ar 50 C b-t the rated press-re of tne bonle s 20 am D Herent flavors may nave slightly different pressures of CO,. The manufacturers of soda are ve& proud of their safe, new plastic bottles which are refillable under certain conditions. In Canada the makers of Big 8 soft drinks have soda fountains in certain grocery storesfor custohers to refill their 2-L bottles. The oolvethvlene tereohthalate (PET) bottles have been a , , , . . great sLccess an0 gone are tne aays of explod ng glass bon es Nev- enneless r is srlll a p ry thar soda IS ess expens ve and O J ~ se s m k

Volume 71 Number 10 October 1994 903