Human Heredity 9th Edition by Michael Cummings

Exercise 4

On ADril 26. 986,one ofthe fourreactors at the Chet"nobyl geMrating station in the Soviet Union metted dov.•n. tt has bee.l'I reood that theplant \Vasrunr¥ng \vith disconMcted s.afety measures. The resultwasfire.chaos,!ear.a cloud of racf:io.active isotopes sore.ading acrossvast re.ache-so eastem E'l.lroPe,and the radioactive contamination ofthousands o! people.
Unfortunat ely,thishuman tra-gedy isnot being investiga*d asit should be. according to scientists \'Yho are trying to leam from it.Cancer-prevefltion Sl)eeia!ist:s claim that there isa lack of resources availableto look at cancer cases in the powlation eXDOsed' to ra-di.ation re-!eased 7om Chet"nobyl.
Sdentistswho'N snt tostudy the .aftermath o Chemobyt face msny obstacles: (1) Thecf:isso!ution ofthe Soviet Union solit admiristr.ative.record keeping, and medk.a!responsr'blities .among Belarus,Ukr.ame,aiid Russ.is; (2) a general decla-lein living standards h.asreduced thele-ve-1 of medic.al core in theare.a:(3) lndividusl doses cannot be reconstructed accurately and e-stimatesof dos.es received by intividua!s havebeen comolka*d by the fact that some of the dose v..•-as external through osureto r.a-di:osctive dust .and cartwasint et"na!through esting contaminated food; and (4) little money is avsitabte for the tyoe-s o large studiesthat .are needed for extracting thebest data.
Het"eare some of the facts-as be-st \Veknow-.about the Chernoby1 meltdov..·n. Theacck!en; reteased .85x Ci
(18. 50,000,000,000,0 0000) lnterru.tion.a!units o5 radioactivemateri-at The releases contaminated .an estim at ed 7
million people to some degree.The exact .amount o5 exoosure depended on loc.ation. \vind direction, length o exoosure, and e. ting habits,as v·.eU asv.hether a person wasa 1iquklator. l'heo...e unfortuna*heroes v.<,ere pressed into savicein a crude cleanup efftrt .afta- theaccident. One hundred thirty-four peopleshotNed signs of .acute radi ati sid:ness immedi.atelyafta- theaccident. Many ofthe 28 ceoole who died from acuter.a&.ation sicknesshad skin lesionscovering 50S6or mor e o theirbodies.A, thefire, 135,0 people ev.srusted the are.a around the reactor,.and S00,000 liquidstors moved in to tryto dectamin:teth.at area.Approximately 17%to d.556 of the iquklators received dosesbetween 10 and 23 r.a-ds(a rad is a unit of radc:ation do-:.e and standsfor ra-cf;.ation absorbed dose).FCf' ccrnpariS-.U.S.safety guidelines
permit an .annual doseto the geMral pu:b6c of O.l r.a-d;nudesrworkers .are permitted 5 rads..
Oesoitethe early confusion. some medic:.!ln ormation isavaitable in Chernobyt's.aftermath.The most comoefting data involveradiation eXPosure .and thyroid cancer.partkularfy in children. According to the lntem.ational Chet"nobyl
Conference (A.Jril 1996). radiation exoosure caused a substantial incre.ase in rePOrted cases of thyroid cancer in Belarus, Ukraine,and some o.arts of Russia,e-speda.!lyin young children:This isthought to be due to exoo-sureto r.a-dl:osctive iodine during the early phases o the accic!'ent in 1986. By the end of 995,.a,poroximstety 8{> c.ases of thyroid cancer had been reood in childret1 \\!ho v.<,ere under a-ge 15.at thetime of d:S-gnosis.Toc!' te.three of these thyroid-cancer victims hsvecf..ed and sever.a!thous.and more cases of thyroid c.snca- are ec*d. lronk.arty,most o5the thyroid c.sncers could
hsve been prevet1ted i!ceoole ln the contaminated .areas hsd taken iodinetablets immedi.atelyafta- the accident Most iodine in the body goes tothe thyroid gl.and; i!enough normal iodine is.avsflable,only a small amoun of r.a-dl:osctive isotopeirradiates the littte gd. v.hose hormoneshelp regu.'.ate gw.vth. More in ormation on the l g-term effects of Chanobyl's exolosion \vii be 1.e.smed in the coming decades,as scientistsand health careworkers assessthefull impact of thisdisaster.
A.ta incre.ase in thyroid cancer v..•-as reported afterChemobyt.Ate these ceoole .at risk of passing a mutant c.ancer gene to thff offspring?