Document zQq5M4doznYb9qrL6Mj99Zngz

< NATIONAL IJSTITOTE OF A H fp iT IS A HBfABQLIO DISEASES f ' L' - ' Pop A. Lawrence Vieto r H. Arcbe-j* Ju ly 29s 1953 A halysis o f samples f o r Fb 210 A fter spendine; considerable time in developing a la th e d / tfe haw analysed th nine w ater and urine-: -epediitim- which you bava" M l s r i t te ^ We aodifi d vfce dithissone le a d determ iim ticn method so t h a t tb# separated le a d i s deposited on a, g lass pl2hehat and counted in a gas flow p ro p o rtio n al counter.' W ran enough c o n tro ls and a spiked s ipls to convince ourselves of the v a lid ity o f the method. The spiked sample showed. m% recovery* 'v.'a jSUn to run sor more m iked samples and p u blish the method . . ; For a1r e l i a b l e count,, one should have n t l e a s t .twice; the back ground which in t h i s case i s approxim ately 50 epau I f a 2k h r* 'u rin e sarmle were concentrated and analysed, i t should contain a t l e a s t ICO dps (50% ijudabtiy). rills would he eq u iv a le n t to 5*9 X 1ST13 .gpam. of Fo2X0* This wooid re p re se n t the le a d formed by tb s decay of 0,0? nicrocurics o f radon. ppQ lfs Of ansdySess Sample asme 100 tal analysed Water (1) W ater.(2) `Wpter (3) P* Lawrence 0 Ponder J* ..Johnson B* H ilport J , Orbene D is tille d n20 epa 61*h kgd* Blvgd, 1^*2 33.1 ih .6 2?*iy Bkgd,. Bksd* Estimated .values PC A 10-4 ue X 10~4 2ii b r , urine D oily absorption 2.0 Calculations not applicable 9Ai 16, 2 . 2.1* ?2 k.5 13.5 The estim ated 2k...'hr* urin e co n te n t was obtained by d iv id in g ty 100, m u ltip ly in g by 1800 (1600 -sOU taken as average 2k hr* urin e o u tp u t), m u ltip ly in g 'by 2 (geometry o f c o u n te r), and d iv id in g by 2*2 X 10 (conversion t-o m ic ro cu ries). The estim ate of amount i n body i s based on th e follow ing infoxviation sup p lied by Dr. P. A* Kehoe (d a ta obtained from one normal in d iv id u a l exposed d a ily to f in e ly d iv id ed lea d oxide f o r two years)* An eq u ilib riu m , w ith re sp e c t to the twodraust concentration of lead, in th e blood and the axiom ra te of load e x cretio n in th e u rin e , was reached in aprroidlnatsly s ix months, a f te r which tho su b ject went along on a p latea u f o r the r e s t o f th e period* In th e two y e a rs , the' asupbejrepcxtimabtseolyrbe3d0 mapgpr(o-0x-i,mO-laitl-ei lmy s/d*am~) go*f"owf`hich Br* KeJS>e* s v d tk vim datse with, s ta b le le a d , but- J% 210 should behave - ' exactly the sane since there i s enough sta b le lead 'present in the tody to act as a carrier. ' ' :' H eins the above -figures,- -at equilibrium . (6 xr*c. o r more o f exposure) !;0f, o f absorbecl. lea d i s re ta in e d end' 60%, i s excreted p e r d~y* Of t h a t e x crete d , $6% i s in the urine * The xcriTS* e x cretio n then re p re se n ts am t h ir d o f the- d a ily in tale* The amount of d a ily ab so rption o f le a d i s thus apnroseirjatoly throe t i r e s the mount ' usd in th e urins* To sake an estim ate of the amount of le a d 210 in the body o f an iridividual expoood fo r over s ix months, one could take If);? ( proportion re ta in e d ) o f tie fount absorbed d a ily andxm u ltip ly by the t o t a l -pusher c f days exposed* Assuming thufc cn& ih ird o f t i e load 210 fofmedrby radon decay in th e body i s excreted in th e u r in e , then the lower, l im i ts of .'the; mathed. would be the amount of le a d 210 formed by the sh e e rp ilc a and decay ts ts e e n 0 .2 sad 0 .3 s ic r o c u r ie s .of rodon. p er day in chronic exposures* For acute, exposures, the lower lim it would probruly be e e v srzl times higher because of le s s excretion* I m -rsiiTG th .it you linger ctes&d the te n ta tiv e end prclisaiftary nature of th is d ata cr-d c.v.fd.ationr* 7' :; c'-blyses Her e performed on xmall c.-m ies (100 m l.) , moot of ths counts wore lo s s than twice . bade ground so t h a t the s t a t i s t i c a l e r r o r in counting was l a r g e , the d ata cf Kehoe's was oVtairscd from only one individual., the, le a d in M s exporinont was adm inistered by a possibly d iffe re n t ro u te , and the chemical for wae probably d iffe re n t* Kfc 0019717