## r P.1 3 

# IORK&-R./V-S

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. BACKGROUN

D INFORMATIO

NRELATE D T O 

# DRAF T ADMINISTRATIV

E EXEMPTION S FO

RCERTAI N

RADO N RELEASE S

I n respons e t o the propose d rul e t o adjus t radionuclid e reportabl e quantitie s (RQs) , EP Areceive d man

ycomment s expressin g concer n tha t mor e than a n R Q o f rado n woul d b e release d commonl yfro mcertai n facilities . Thes e facilitie s includ e a variet yo f minera l extractio n an d processin g plants , man y o f whic h produc e larg e volume s o f lowactivit ywaste s tha t ar e store d on-sit e (e.g. , gypsu

mpile s a t phosphat e fertilize r plants) . I n respons e t o thes e comments , EP

Ai s considering exempting administrativel ycertai n rado n release s fromthe R Q reporting requirements . Eac h adminisCraCiv e exemptio n woul d hav e t o b e supporte d wit h evidenc e a s t o wh ythe governmen t woul d neve r wan t t o b e notifie d o f the rado n release . Thi s pape r summarize s background informatio n o n rado n release s fro m certai n facilicie s o r accivicie s tha t coul d b e exempte d fro mthe R Q reporting requirements . I t describes , wher e applicable , ho wthes e rado n release s ar e bein g handle d unde r othe r regulatoryprograms . Th e pape r als o present s preliminaryinformatio n o n che hazard s associate d wic h che rado n releases . Thi s background informacio n i s inCende d Co hel p the Radionuclid e R Q Workgrou p decid e whethe r t o exemp t the rado n release s fro mthe reporting requirement s o f CERCL Asectio n 103 . Phosphat e Fertilize r Plants . Including Phosphogypsu mPile s Th e productio n o f fertilize r use s approximatel y8 0 percen t o f the phosphat e roc k mine d i n the U.S . Concentration s o f natura l uraniu man d it s decayproduct s (including radium , the immediat e paren t o f radon ) i n phosphat e deposit s rang e fro

mte n t o on e hundre d time s the concentratio n o f uraniu mi n othe r natura l rock s and soil s (4 9 FR 43914 , Octobe r 31 , 1984) . O n Apri l 6 , 198 3 an d Octobe r 31 , 1984 , EPA' s Offic e o f Radiatio n Program s announce d i n th e Federa l Registe r (4 8 FR 1507 8 an d 4 9 FR 43906 ) tha t goo d reason s existe d t o exclud e radionuclid e emission s fro mfertilize r plant s fro m regulatio n unde r the Nationa l Emissio n Standard s fo r Hazardou s Ai r PolluCanC s (NESHAPs) . Th e reason s ciCe d fo r Chi s exclusio n wer e a s follows :

o Fercilize r planC s releas e radionuclide s inc o the ai r primaril yi n the for mo f dus t particles . Particulat e emission s fro

m ne wo r modifie d fertilize r plant s ar e controlle d b

yne wsourc e performanc e standard s issue d unde r Sectio n 11 1 o f the Clea n Ai r Act . Existing fertilize r planC s ar e regulace d fo r particulat e emission s b

yStat e implementatio n plan s a s require d byth e Clea n Ai r Act . Thes e particulat e emissio n standard s an

d conCrol s limi c effectivel yradionuclid e releases . o Th e risk s t o nearb yindividual s an

d the tota l populatio n risk s du e t o radionuclid e emission s fro m phosphat e fertilize r plant s ar e insignificant . Th e technica l analysi s supporting thi s conclusio n i sP.1 4

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# DRAF T •2

- presente d i n a relate d Background Informatio n Document. 1/ Th e Federa l Registe r notice s an d supporting Background Document , however , do no t addres s release s o f radon , whic h i s a ga s rathe r than a particulate . Also , thes e source s analyz e onl ystac k emission s a s oppose d t o release s fro m phosphogypsu

mpile s (fertilize r plan t wast e materia l tha t i s store d on-site) . I n fact , the Octobe r 31 , 198 4 notic e (4 9 FR 43914 ) state s that :

EPAdi d no t propos e radionuclid e standard s fo r thi s sourc e becaus e i t believe d tha t suc h waste s woul d b e mor e appropriatel yregulate d unde r the Resourc e Conservatio n and RecoveryAct . Afte r considering al l comments , EP Ai s reevaluatin g the nee d fo r radionuclid e standard s fo r thi s source . Preliminaryris k estimate s indicaC e Cha C individua l lifecime risk s fro mexposur e C o ai r emission s fro mthes e pile s mayb e a s high a s eigh t i n te n thousand . Populatio n risk s mayb e o n the orde r o f on e fata l cance r pe r year . Th e Agenc ywil l continu e it s examinatio n o f the nee d fo r a standar d fo r thi s sourc e category . Sinc e thi s notice , EP Aha s complete d studie s o n phosphat e roc k beneficiatio n tailing s an d ha s determine d tha t regulatio n o f thes e tailing s a s hazardou s wasC e unde r RCR Ai s no c neede d (5 1 F R 36233 , OcCobe r 9 , 1986) . A simila r stud

yo f phosphogypsu

mreportedl yi s almos t complete . Base d o n a conversacio n wit h Jame s Hardi n o f the Offic e o f Radiatio n Programs , however , a fina l determinatio n wit h respec t t o ai r emissio n standard s fo r phosphogypsu

mpile s ha s no c bee n made . Independen t calculaCion s sho wCha C rado n release s fro mphosphogypsu

m pile s probabl yapproac h an d mayexcee d a rado n emissio n sCandar d fo r remedia l accion s a C inacCiv e uraniu mmil l Calling s piles . Th e rado n exhalacio n rat e fro mground contaminate d wit h radium-22 6 (the paren t o f radon-222 ) ca n b e calculate d usin g th e following equation:2 / \ 0. 5 J - Ap E (AD ) where ; J - rado n exhalatio n rat e i n pCi/cm2-sec ;

A- concencracio n o f radium-22 6 i n ground (pCi/gm) ; p - j bul k densiCyo f Che soil , typicall yabou t 1. 7 gm/cm3 ;

1/ EPA , Radionuclides : Background Informatio n Documen t fo r Fina l Rules . Volum e II . Offic e o f Radiatio n Programs , EP A520/1-84-022-2 , Octobe r 1984 . 2/ Nuclea r RegulatoryCommission , Fina l Generi c Environmenta l Impac t Statemen t o n Uraniu mMilling . NUREG-0706 , Septembe r 1980 .P.1 5 

# DRAF T

E - the fractio n o f rado n tha t escape s fro ma particle , typicall ytake n a s 0. 2 fo r uraniu mmil l tailings ; *\

- the radon-22 2 deca yconstan t (2. 1 x 10- 6 sec-1) ; an d D - the diffusio n coefficien t fo r rado n i n soi l (cm2/sec) . Accordin g t o the Nationa l Counci l o n Radiatio n Protectio n (NCRP),1 / the radium-22 6 concentratio n i n gypsu mwast e range s generall ybetwee n 3 0 an d 4 0 pCi/gm . Value s fo r the diffusio n coefficien t (D ) i n the literaCur e varyove r four order s o f magniCude , depending o n Che soi l moistur e an d othe r factors . Accordin g t o a stud yo f Florid a phosphogypsu mstockpiles,4 / the moistur e conten t o f phosphogypsu mrange s fro

mthre e percen t t o roughl y1 8 percent . Usin g thes e moistur e conten t value s i n a n equatio n fo r D obtaine d fro ma Departmen t o f Energ ydocument,.5 / value s fo r D fo r phosphogypsu mmigh t vary betwee n 5x10- 2 cm2/se c an d 1x10- 3 cm2/sec . Plugging al l o f thes e value s int o th e abov e equatio n fo r the rado n releas e rate , initia l estimate s o f rado n .release s fro

mphosphogypsu

mpile s rang e fro

m5 pCi/m2-se c t o 4 0 pCi/m2-sec . I n comparison , EPAha s issue d unde r 4 0 CFR Par t 19 2 a rado n emissio n standar d o f 2 0 pCi/m2-se c fo r uraniu mmil l tailing s piles . EPAha s state d tha C chi s emissio n standar d provide s "excellen t protectio n o f publi c health , safety , an d the environment " (th e lung cance r ris k t o the mos t expose d individua l woul d b e reduce d t o a fe wchance s i n a thousand ) (4 8 F R 598-599) . I n conclusion , insufficien t evidenc e ha s bee n obtaine d t o conclud e tha t the governmen t woul d neve r wan e C o b e noCifie d o f rado n release s fro m phosphac e fercilize r planC s an d phosphogypsu

mpiles . Previou s regulacory decision s examine d C o dat e ar e inconclusiv e wit h respec t t o thi s issu e an d preliminarycalculation s sugges t tha t rado n release s fro msome phosphogypsu m pile s mayb e a concern . EP Ai s continuing t o gathe r an d evaluat e additiona l informatio n C o hel p reac h a decisio n o n ho wches e rado n release s shoul d b e handle d unde r Ch e R Q rulemaking .

1 / NCR P Repor c No . 77 , Exposure s fro mthe Uraniu

mSerie s Wit h Emphasi s o n Rado n and It s Daughters . 1984 . 4 / Alexande r Mayan d John Sweeney , Evaluatio n o f Radiu man d Toxi c Elemen t Leachin g Characteristic s o f Florid a Phosphogypsu mStockples . Burea u o f Mine s Repor t o f Investigation s No . R I 8776 , U.S . Departmen t o f the Interior , 1983 . 5 / Departmen t o f Energy , Pathwa yAnalysi s an

d Radiation-Dos e Estimate s fo r Radioactiv e Residue s a t Formerl yUtilize d MED/AE C Sites . ORO-832 , Dist . CategoryUC-70A , Marc h 1983 .