U.S. DEPARTMENT Of COMMERCE National Technical Information Serwice

PB-260 212

RADIOLOGKAL CONTENT OF COLORADO RIVER BASIN

BOTTOM SEDIKNTS 0 -

PUBLIC HEALTH SERVICE, DENVER~COLORADO

JUNE1963 bIBLIOCRAPHIC DATA 2. 3; Recipient's Accession No. MEET PB-260 212

8. 8. Title and Subtitle 5. Report Date Radiological Content of CoSorado River Basin Jun 63 6. Bottom Sediments, Auqust 1960-Auqust 1961 '. Author(s) 8. Performing Organization Rept. No. PR-Ig . PerforminR OrganiFation Name mnd Address 10. Prolect/.l ask/U'ork Unit No. Public Health Service; Denver, Colo. Div. of Water Supply and Pollution Control. 11. Contract/Grant No.

-~ 2. Sponsoring Organization Name and Address 13. Type of Report & Period Covered

1 5. Supplementary Notes Report on Colorado River Basin Water Qualit> Control Project,

6. Abstracts Data on the radium content of bottom sediment material collected in 1960 and 1361 throughout the Colorado River Ba.sin is provided, For the sediment surveys reported, 254 samples representing 121 different sampling stations were collected. Forty-nine samples representing 20 different sampling stations were collected in locations where the sed2-ment was not influenced by uranium mining and milling activity (background locations) , Detailed tables of the results of radium-226, gross alpha, and gross beta determinations on the sediments collected are included.

7. Key Woads and Document Analysis. 170. Descriptors

7b. Identifiers 0pen;Ended Terms Colorad o River Basin Public health * Radioac tive con tamination Leaching Radioactive wastes Hydrology *Sediments *Water pollution sampling uranium ores 7c. COSATI Field 'Group 8H

18. Aoailahtlity Statement 19. Security Class (This 21. No. of Pages Report) XED 62 20. Sxurity Class (This 22. Price Page UNCLASSI FlED RADIOLOGICAL CONTENT OF . . '; COLORADO RIVER BASIN BOTTOM SEDIMENTS I' August 1960 - August 1961

..I

U. S, DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Public Health Service Bureau of State Services Division of Water Supply and Pollution Control Region VI11

Colorado River Basin Water kuality Control Project ACKNOWLEDGMENT

The generous cooperation and assistance of the following in the conduct of the field sampling are gratefully acknowledged:

U. S. Department of Interior, Bureau 3f Reclaamtioc, Region 3, Boulder City, Nevada; National Park Service, Lake Mead National Recreation Area, Boulder City, Nevada; Fish and Wildlife Eervice, Havasu National Wildlife Refuge, Parker, Arizona, and Imperial National Wildlife Refuge, Yuma, Arizona.

'fie cooperation uf the sew9 Basin states in all Project activities is greatly appreciated. Id?. . . KAI)IOLOGICAL CONTENT OF ,"; . ! COLORADO RImR BASIN BOTTOEI SEDIPIENTS August 1960 - August 1961

J INTRODUCTION AND BACKGROUND

Studies which concern the disposal of and subsequent fate of radioactive materials in the water environment must consider all phases I of this environment. This includes the water itself, suspended and bottom sediment material, fish, algae and other aquatic biota. Many i I inveatigators have demonstrated that sediments and aquatic life can acctimulate significant amounts of radioactivity from overlying waters. The radioactivity contained in these sediments end possibly that from decaying aquatic life can be leached back to the watei phase. f -' f a In the United States vast deposirs of uranium ores are located in the Colorado Plateau area, central Wyoming, and the Grants-Ambrosia Lake areas of New Mexico, with lesser deposits in the western Dakotas, southern Oregon, and northeastern Washington. There were in 1961 twenty- six operating uranium mills and four upgrading plants in the western United States. Table I presents a listing of these facilities and their design capacities. From this tsble it is seen that, on the basis of design capacity, about 30 percent of the total national uranium ore production is milled in the Colorado River Basin. With respect to the waters of the Colorado River Basin, major sources of radioactive con- tamfnation have bem those associated with the mining and milling of these uranium-bearing ores. Figure 1 shows the location of uranium mills and upgrading plants in the Colorado River Basin.

Uranium-bearing ores generally average about 0.25 percent uranium as U3O8 (2). The milling processes are designed principally to extract uranium froF the ore. The bulk of the ore processed becomes a waste product containing large amounts of radioacti-!e constituents other than the uranium originaLly present in the raw ore. Detailed ""t . descriptions of processing and waste disposal operations at various uranium mills are given in recent Public Health Service reports. (1)(3)

Radioactive waste products associated with discharges from uranium milling operations include uranium, radium, thorium, and all of their decay products in varying amounts. By far the most important of these radionuclides is Ra-226 because cf its extremely low Maximum Permissible Concentration (MPC) in water (4)(5), its bone-seeking characteristics, and its long half-life of 1.22 years.

Studies of the effects of waste discharges from uranium mills on the waters of the Colorado River Basin have been carried out by the ,. Public Health Fervice since 1950. In 1950 samples of river water were collected at locations above and below several uranium mills. These data showed thae the dissolved radium content of river water below uranium mills was increased considerably by waste discharges from the ,:

c I

la u YlLL SITCS

COLORADO RIVER BAS1 N WATER QUALITY CONTROL PROJEC f ¶CALL IN MlLf 9 DEPARTMENT OF HEALTH, EDUCATION,^ WELFARE PUBLIC HEALTH SERVICE MA a --REGION Vlll DENVF R,FIGURE COLORADO 1 ,

TABLE I - Uranium Proccssin!: Plants - 1561 (1)

. Desi n Cap city Figure 1 (Tons of Oi-e CoInpaiijr Location 02 Mill Cotie No. per Day)

A. COLORADO RIVER BASIN U. S.Atomic Energy Coinmission,11 i-!o n t ice 1lo , u . 1 350 Climax Uratiium Co. Grcm Junction, Co lo. 2 330 Guiinison Mining Co .Lj muulinisoil, Culo. 3 200 Kerr-McGee Industries SIILprOck, 01.1 N. M. 4- 300 Rare Metals Corp. 02 AmericizAi Tuba City, Ai-iz. -, 300 Texas-Z inc Minerals C91-p. Mt-::icaii Hat, Utah 6 1,030 Trace Elemcnts Co. Maybe 11, Co lo. 7 3 00 Uaion Carbide Nuc lcar Co. Ri.?le, Colo. 9 1,000 Ucion Carbide iu’crclear Co. Uravan, Cu lo. ,-., I, 000 Uranium Reduction Co. Noab, Utm 10 1,500 Vanadium Corp. 0: America Duranzo, Co 10. 11 7 50 TOTAL 7,230 Union Carbide Nuc lear Co .a/ Green River, Utah 12 Unioa Carbide Nuclear Co. 1 j 31 S 1ic!c Rock C,>lo. 13 V&LiadiurliCorp. Arilerica oE -3-1- PI.;, r i cme il i: V a 11 e y , Utah 14 Vanadium Corp. of America 31 Na t ur ita, Co lo. 15

B. OTHERS Cotter Corp . Canon City, Colo. 2 00 Anaconda Co. Graiits , N .PI. 3,000 I Homes take-W. M. Par Lr,sevsL/ Grants, N. M. 7 50 H3mestake-Sapin Partners Grants, N. M. 1,500 Kermac Nuclear Fucls Corp. Grants, N. M. 3,300 Phillips Petroleul,i Co. Grants, N. PI. 1,725 Lakeview Mining C0.11 Lalceviei:, Ore. .? 10 Mines Development, Inc. Edgemoiit, South Dai:o ta 400 Susquehanna-Vestern, Inc. Fall City, Texas 2 00 Vitro Cnemical Co. Salt Lake City, U. GOO Dat.:i EXiniiig Co. Ford, \‘ashiiigton 400 Federal-Raiorock-Gas Hi11s Partners Fremoiit CO., kyoning 520 C-lc~beMining Co Ncl trona Co. , L!yoining 490 Pc trotoinic s Co .-21 Carbon Co. , \:‘yomiiig 2co Susquehantia-l:ester.n, Itic. River ton, l.lyoniirig I; 00 1Jtah Construction and 14iiiiiiZ Co. Fremont Co., Kjroming 520 lTestern Nuclear , Iiic. Jeffrey City, l!yo!ning 345 \?yo. Mining & Milling Corp.- 2 31 Natrona Co. 1:yomir.z TOTAL 15,620

-11 Inactive -21 Under construc tioil -31 Upgrading plants . ,...... - -...... -.. . .) . I._.-I - -

3

, milling operations. In the fall of 1955 a second short-term survey was performed on streams in the vicirrlty of eight uranium mills, seven of which were in the Colorado River Basin (6). At this time, in addition to river water, bottom muds 3nd biota (algae and insects) were collected. Although radium analyses were not performed on the river muds, gross alpha and beta analyses showed accumulation factors of 100 times back- ground or more in the muds. A detaile.J survey was conducted in 1956 (7) on two of the most seriously polluted streams in the Colorado River Basin. The latter study showed that radium content of river muds immediately below che uranium mills was 1,000 to 2,000 times natural background concentrations. !

The Animas River surveys :6) (9) were the first studics which pro- vided detailed information concerning the effect of ladium-bearing bottom I sediments upon the stream environnient. These studies clearly demonstrated that considerable radium was leached out of the sediments with the result that the dissolved radium content of the river water was above the Maximum Permissible Concentrat ica value for radium-226.

One of the questions raised in the Animas River studie; w3s that of the leachability of radim from uranium mill waste solids and river sediments, and the factors w:.ich influenced such leacSing. Accordingly, detailed laboratory investigations were undertaken along these lines (io). These studies showed that the major factor coatrolling leachability of radium was the liquid-to-suliu ratio (volume of liquid per unit weight of solids). A more detailed discussion of these findings is presented in Appendix A. i The objectives of rhe three Basinwide sediment surveys conducted by the Colorado River Basin Project during August 1960 to August 1961 were to determine: (a) che radioact;.-ity Luruen of Basin sediments; (b) distribution of tltis radicactivlty throughout the Bas.in; (c) the difference between natural background cotrcentratio. 3 of radioactivity, and radio- activity resulting from waste disposal operations; and (d) effects of river hydrology on sediment deposition and tran..port.

Within the Colorado River Basin, parti3:ularly the upper portions, most of the annual surface runoff is the result of snow-meit. The first melts usually begin each year in early or mid-April, with peak streamflow around the early part of June, Fiows subside throdgh the .nonth of July and reach base-levels in the early part of suun:erF During late summer and early fall Local ititensc rainfalls may be frequent and produce brief periods of sonewhat higher- flows. From late September until the beginning of snow- melt tne foilowing April, streantlows are fairly conscanf and maintained at minimum levels. Figures 2, 3 and 4 present hydrographs of three typical USGS gaging stations in the Up?et Fasin.

Flow patterns are distinctly different in the Lower Basin Selow Hoover Dam. In the area from Hoover Dam to the Arizcna-Mexico Border, . i'& ,s-.... .*.> 1' ..**.. ,.. . .-, . Y..... Y'

HYDROGRAPH Of COLORADO RIVER I I NEAR CISCO, UTAH Aug. 1960- Sept. 1961- COLORADO RIVER BASIN WAT ER QUAL1 T'f CONTROL PRO JE CT I i 4,000 4- 0,000 I.

...oj,

I I i

LUO. 1960 SURVEY PUQ. 1961 SURVEY PERIOD I I /-

AUO. SEPT. OCT. I JUNE JULY AUB. SEPT. 1960 1961

Figure 2 6,000

HYDROGRAPH OF GREEN RIVER AT GRElEN RIVER, UTAH Aug. 1960 Sep?. 1961 - - r.000 COLORADO RIVER BASIN WATER QUAL1TY CONTROL PROJECT

B,000 -I- H HI MARCH IS61 SUIIVCY \UO; 1960 SURVEY PERIOD 4 $300 I

NAY. se PT. OCT. NOV. L,C. 1 JAN. FEB. I MARCM I IS60 FIGURE 3

-_ -

...... -- I(-I

1 I I I I I I I -7 HYDROGRAPH OF COLORADO RIVER 1 AT LEE'S FERWV,ARlZOMA I AUS 1960- Sap?. 1961 COLORADO RIVER BASIN ,,a00 WATER QUALITY INTROL PROJECT i 7I I

HI MIRCH,IQOISURI AU& is61L SURVEY )0.1960 SURViY PERIOD PERIOD PERIOD + ,000 1-

I MARCH APRIL YAY JUNE JULY AUO. SEPT. AU8. SEPT. OCT. nov. DEC. I I FIGURE 4 I960 .-SI- . .-._ C,

4

streamf lows arc i:lghly regulated by rcled;cs and divc-rsioris Trcr.1 large im- poundments on thc nain stem and major tributarics. B typical hydrograph is given in Figure 5 for the USGS g,iging station inmediately below Parkcr Dam in the Lower Colorado River Basiii.

Three Basinwide strear sediment survcys have been carried out to date and are rcportcd on h1:rc. Tkic dates oE the thrcc field surveys were as follows:

:...I ; I..- I. I..- .. Fizst survcy - Lwgust 8-24, ?9GO !' . ... . Second survcy - P!arch 5-23, J961 Third survcy - -15, 1962

The above sainpl irig periods wre selected to coinc..de ~i.thcertain hydrologic conditions in the Upper Basin. By rcferencc to Figures 2, 3, and 4, it is seen that the first survey vas c.mductcd won after the spring snow-melts. 'Ihesc sncw-melts produccd high flows whicl: resulted in scouring of the river bottom and transporr- large quantl5cs of sediment to the Lower Basin.

This survcy period was representative of rclacively clean river beds. The second survey of followc.cl an extended pcri-od of' low flow with resulting accunulation uf buztw sediment rnatLria1. River conditions Juring thc third survey of August 1961 iipproxirmted those of the August 19GO study.

Several factc.rs wre considcred i.n selecting.the various stream sampling stations. The inajdjr criteria mre the need to obtain 'data on back- I ground radioactivity levels of sedimcnts upstream from uranium mining and milling activity and the dcpcsicion of radioactive sediments belc;w such activity. Figures 6, 7, 8, and 9 stlow locations of ail sediment stations .. \. with the exception of the La!ce Picad samples. Results of Laltc Ncad sampling are givcn later in this report. The 1;li-gc mijority of stations mrc situated below uranium milling and mining areas. A complrte dcscription of all stations is provided .in Appendi:; 8. , .iy < Several inetliods were cnploycd in collectim of strcan sediments. 2 Samples were obtained eitkr by ail Ekman dredge, Pctersen drcdgc, or by' f hand. The majority of the scir!ip?,cs rcpresmted a coiriposite of sediment a,t 6 quarter-points across the width of r!ie stream, and were collcctcd by hand I'!4?-. when waditig was fcasbble. When this vas not pvssible sarnplcs were ta..en by means of a dredge lovered from a h:i

Thc conduct c' the threc Basininde sedimcnt surveys included collcc- tion of botrm inuds fron LaKe liead. In addition; n special mud sampling study was conducted during clctobcr 24-28, 19GQ, of Lake Mead in conjunction 4~,000 I H COLORADO RIVER BASIN I I LUQ. 1960 SUAVE WATER QUALITY CONTROL PROJECT PERIOD I AU8.1961 SURVEY 1 PERIOD

1 "1,

-9,000- !! 3 C E , :. '! -apoo- 1 .I:> i J 't :.

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FEE. APRIL JUNE JULY AUO- . SECT. 1#61 JAN. FIQURE 5 AUQ. SEPT OCT. NOV. OEC. J IOIO

.. .

I. CRAIG

OURAY 1 F i [z1 URANIUM MILL I I SEDIMENT SAMPLING STATION LOCATIONS AUG. 1960- AU6.1961 COLORADO RIVER 8ASI N WATER QUALITY CONTROL PROJECT

DEPARTME. dlf OP MEALTH.EDUCATIOP~~WELFARI PUBLIC HEALTH SERVICE MOlOI VIII ocwvnn,cowam I I

n SEDIMENT SAMPLING STATION LO CATIONS m AUG. 1960- AUG. 1961 COLORADO RIVER BASIN WATER QUALITY COFlTRGi PROJECT -J I 0 IO PO 30 40 EWITMENT OF HEALTR,EDUCATION,~WELRRl URANIUM MILL PUBLIC HEALTH SERVICE SCALE IN NILES I MQtON VIII 0 LNVE ll ,COLD. @ URAN:UM MILL

SEDIMENT SkMPLlNG SVATION LOCATIONS 0 10 20 10 40 SO AUG. 1960- AUG. 1961

SCALE IN MILES COLORADO RIVER BASIN WATER QUALITY CONTROL PROJECT DEPARTMENTOF HEALTH,EDUCATION,B#fELFAA PUBLIC HEALTH SERVICE REOlON VIII DLIVER,COLORADd t

SEE FIGURE 12

NEEDLES

SCYLE 111 MILLS

ISE o I M ENT SA M P L I PI G s TATI oh LO C AT1 0 N S AUG. 1960 - AUG. 1961 COLORADO RIVER BASIN WATER QUALITY CONTROL PROJECT ’ DEPARTMENTOFHEAI,T~.EDUCATION.8rWEL~RE PUBLIC HEALTH SERVICE I RCOIOW VIII DEWVER,COLORAOO 1 FIGURE 9 5

w,th t..e annua Lake survey by the Bureau of Reclama rity in report presentation, thc ~htafrom Lake Mead are considered separately from the other rcsults.

A11 samples frow the surveys were analyzed for radium-226 content. All samples from the first Basinwide sedilaertt survey were also analyzed for gross alpha and gross beta radioactivity.

PRESENTATIOiJ OF DtITA

The data obtraincd from the threc Basinwide sediment surveys have been subdivided into several groups in order tu provide clarity and in order to obtain better interpretation. Median valucs, as well as range and average, arm shown sLnce i.t was noted chat a small nunber oi very high results in a data group significantly affected thc average.

Gross radioactivity data have been Gmitted from the detailed tables because gross radioactivlly determinations were performed only on the samp?es collected in August 1960. Averages and ranges of gross aipha dnd gross beta determinations have, however, been included in summary tables.

The detailed tables include individual results for riffle and pool samples collected at various sampling 1ocati:ri.s. '

A. Backnround Sediments

Bottom sediment som?les were collectcd at 20 locations unaffected by uranium ,nining and milling activities. The radioactivity levels of these sediments are indicative of natural background levels. Individual data for this group of stations are presented in Table I1 whereas average and median values 3re given in Table 111.

The data in Tablc I1 shov chat with Lhc exception of five values, the Ra-226 content of Basin sediments icpresenting not ral background conditions is 1.5 ppc/g or 1r?ssb Table 111 shows th3L the average Ra-226 level is J..1 ppc/g for the 45 samples obtained. The values in Tables I1 and 111 confirm earlier survey resu1:s on natural hackground levels of radium in rivcr sediments (8.9). ___..-...,_-...,-.l.*C " . -. - . I _--."- - - f

6 I' ! TALLE I1 Radioactivity - Natural Background Sediments August 1950 - August 1961

Radium-226 (uuc/p,) Station Location ~'LLIL:. 1960 March 19Gl Aug. 1961

0.5 Lay Creel: -- 1.6 1.8 3 Yamya l?ivc.r -< 1.0** -- -0 i 7R** Green River .-< l,O*kJ: 1.0 1.0 7P*** Gz-em River 0.8 -- -- 9R Colorado River 1.4 1.4 1.0 9P Colorado Kivcr 2.1 1.a 1.2 17 Green River 0.9 0. G 0.9 33 Mocnkop 1 Wash 1.3 0.9 1.1 52R Ssn Juan River 0.3 1.2 0.8 52P San Juan River -i loo** 0.7 1.1 57 Animas River 1.3 1.4 1.1 62R San Miguel River -< loo** 1.1 1.0 . 62P San Miguel River I .o 0.9 0.9 71 Gunnison River 1.6 1.1 0.9 72 Tomichi Creek 1.2 1.2 1.1 74* Eagle River 1.3 75 Colorado River 1.5 76 Roaring Fork River 1.2 78 Gunnison River 0.8 79 Tomichi Crees 00 9 80 Uncompahgre River 1.2 81 ,?n Miguel River 0.8 82 Little Snake River 1.2 83 Fhite River 0.9

*Stations 74-83 collected December '1961 **Not used in average *** R=Rif f le; P=Pool

TilBLE I11 Summary TJblc on RadioactLvr~yof Nairural Bscl.Rrc.und Scdiments

Radioa. tivity - ppc/g Gross Alpha* Gross Bcta* Radium-226

AVCl age 7. ? 44 1.1 Med i an 8.4 44 1.1 Range 3.1 - 13 19 - 84 0.6 - 2.1 Nuvber of Samples 14 14 45

*Gross activity only dctermincd For .lugust 1950 Survey . ,. .. ._<% I... - _.,.. . . . - . . , . ., ..~..

TABLE IV Radioactivity - Plain-Stern Colorado River Boriom Sediment Augus!: 1960 - ‘\ugust 1961

Radium-226 (u,:c/K) Station Locat ion Aw. 1960 FIarch 1961 AUQ. 1961 75** Above Glenwood Springs, Culo. -- -- 1.5 9R At Silt, Colo. 1.4 1.4 1.4 9P At Silt, Colo. 2.1 1.8 1.2 1OR Above net? UCb!C Uranium Mill at Rifle, Colo. 1.5 1.9 1.1 LCP Abovc new UCNC Uranium Mill at Rifle, COlOm 2.4 1.9 0- 11K Below Rifle, Colo. 2.8 1.2 1.0 11P Below Rifle, Colo. 2.2 -- 25* 12 At Debeque, Co1.0. 1.9 2.7 1. 9 13R Above Grand Junction, bolo. 2.2 1.9 2.1 13P Above Grand Junction, ColG. 1.5 -- 0- 15 At Lorna, Colo. 1.0 2.2 1.5 163 At Westwater, Utah 1.7 1.8 ,100 16P At Vestwater, Utah 1.2 -- -- 19 Above Dolores River 2.1 i. 5 1.2 21 Belov Dolores River 4.3 3.2 2.0 22 3 miles bclov Station 21 1.5 2.0 2.2 23 Above Moab, Utah 3.1 3.1 1.9 24 Below Moab, Utah 3.0 2.8 1.9 24.5 At Hit?, Utah 1.3 1.1 34 At Lee’ * Ferry, Ariz. 1.3 1.3 1.7 38 Below Hoover Darn 0. 9 0.3 1.1 39 Immediately above Davis Dam 1.5 2.3 2.0 40 3 miles abovc Davis Dam 0.6 0.9 0.8 41 At Needles, CaliE. 1.0 0.4 0.4 42 0.5 mi. abovc Par!:cr Darn 2.6 2.2 1.6 43 Lake Havasu, 1 mi. above Parlcer Dam 3.3 2.3 2.2 44 4 mi. above Parkclr Dam 2.3 1.8 3.1 45 At Parkcr, Ariz. 1.3 -_ 1.1 46 4 mi. above Imperial Darn 0.8 0.4 1.1 47 0.5 mi. above Imperial Dam 1.1 0.8 0.8 48 1 ilii. above Imperial Dam 0.9 0.5 0.9 49 ‘It Yumcl, Ariz. -.= 1.09: 0.8 0.5 *Not used in nverase JcfGedirnent sample collected 8

B. Main-Stcm Col.orado River Sediincnts Individual data are presented in Table IV on die radioactivity content of bottom sediments collected from the maIn-stcrn Colorado Rivcr. Excludirrg Lake Mead starions, a toL.11 uf 27 locarivns were sanplcd. Thesc stations cover the Colorado River froin 1.0 miles above Glenwod Springs, Colorado to Yuma, 112 Lzcma. Four stat ions arc wi.;,riii tbc confincs of Lakes Havasu and Mohave.

Table V presents a sunmary 01 radioscLivily resulLs for all sediments collected from the main-stem Colorado ;?i\-er.

TABLE V Sunmarv Table on RadioactiviLv of ILiin-Stem Colorado River sediments

Radioact-ivitv - uuc/n Gross Alpha+< Gross Beta* Radius-226

Average 10 4 0 1.7 Median 10 34 1.5 Range lo%- 27 14 - 84 0.4 - 25 Number of Samples 30 30 84

'VGross activity deteimined for August 1960 Survey only

The data in Table IV show a s:'.zeable variation in radium cmtent of main-s tem r;iver botton sediments. The 84 indi-vidual sampling results have an riverage of 1.7 ;iyC/g radium with a range of 0.4 - 25 ppc/g. The twelve saiiiples collec.i:zd 2rom L'our stations in Lake Havasu and PIohave (Stas. 39, 4-2, 43, at:d 44) belw:; t,ake Plead :?sve an average radium content of 2.3 p;lc/g .iiith a range or 1.5-3.3 ppc/g. A1s.o the three stations below Lake Nead and La!ce Havasu (Stss. 3E, 4C, 41) and all. river stations down- stream of Ln!ce Havasu (Stas. 45-49; see Figure 9) slioti a composite average Ra-226 content of 0.8 ppc/g .c;lith a ranse of 0.4-1.3 ppc/s lor 22 samples.

1\11 sediments collccted Iron ~hcciskit rivcr st-ations belox Lake Mead shov radtoacLivi-ty rcsui ts L'I cnc rnnge cf: natural background., By reference to radroact-vity values Cur Lakes HdJasu and Plo:iave given above and those Lor Lake Mead to be pi-escntcd later in this report, these data demonstrate that these three La!:cs arc collectively the final resting place fer radioactive sedimcnts discb-reed abovc Lake Mad. This observation will subsequently be discussed in grcatci' detail.

C. LOCa'iiOnS Ililmediatcly DObJnS trcarn from Uranium Mills

In order to illustrate thc cffcct of uranium mill wastes upon down- stream river sediments, ;t is dcsirablr Lo group the da:a from stncions located immcdiately below uranium milling activities. Table VI presents these stations arrangcd in downstream order from the lJpper Basin to the Lower Basin. Table VI1 ofEers a sunmsry of the data information in Table VI. TABLE VI Radioactivitv - River Bottom Sediment I~mediatelvBeloti Uranium Mills

Rad ium-226 (uuc /E) Station Loc a t ion Aun. 1960 March 1961 AUP. 1961

1 Lay Creek 76 34 0.9 1.5 Lay Creek 0- 1s 2.1 1OR Colorado River 1.5 1.9 1.1 1OP Colorado River 2.4 1.9 -- i 11R Colorado Rivez 2.8 1.2 1.0 11P Colorado River 2.2 0- 24 73 Tomichi Creek 1.3 -- -- 70 Gunnison River 1.4 0.8 0.7 5 9% Dolores River 2.9 5.9 1.4 59F Dolores River 1.9 2.4 2.1 6LR Dolores River 1.6 00 1.0 61P Dolores River 5.8 3.4 1.9 6 3R San Miguel River 4.7 1.4 1.9 63P San Eliguel River 11 1.5 1.3 65 Saa Miguel River 7.5 9.9 11 24 Colorado River 3.0 2.8 1.9 18R Green River 2.3 1.2 1.2 18P Green River 1.5 1.8 1.7 5 GR Aniinas River 8.6 46 2.6 5 6P Animas River 19 38 6.2 50R San Juan River 1.2 0.8 ' 0.9 50P San Juan River 1.9 -- -0 27 South Creek 2 75* -- 7.6 31R San Juan River 1.7 1.7 0.4 31P San Juan River 1.8 2.9 0.8 , *Not used in average Radioactivitv - (uuc/g) Gross Alpha* Gross Beta* Radium-LZb

I Average 46 97 6. G Median 21 55 1.3 Xange 1.9 - 1-2,;:; 1.5 - 1310 0.4 - 275 Number of Samples 23 23 E5 '*Gross activity determined for August 1960 Survey only

Comparison of the above data wth tlrat of Tables 111 and V is 01

p ,', interest. It may be seen that tlre average radium conient of sediments +. is d obtained itmediately below uranium nil1 locations about six tines that of background sediments and four tines those collected from the main-stem Colorado River.

D. Maior Sub-basins

In order to observe the radicactivc sediment disiribution within major sub-basins oE the Colorado Xiver Basin all sampling stations have i , been grouped according to the following sub-basins: y... .._ (a) Green River; (b) Upper Main-Stem; (c) San Juan, and (d) Lower Main-Stem. Figure 10 shows all of the major sub-basins of the Colorado Bas in.

No samples were taken from the Little Colorado and Gila Sub-Basins, because uranium activity is minitila1 or absent in these areas.

Table VI11 presents the radioactivity data for each of the major sub-basins of the Colorado Basin. The Upper Plain-Stcm Sub-Basin h3s been further brolcen down into the Gunnisou River system and the San Miguel-Dolores River system in order to better evaluate the contribution of radioactive sediment from these two systems.

3' Table IX presents a surr.mary of the data given in Table VIII. Several 3 interesting observations are apparent 2ron this table. Of the iour major sub-basins it is seen that the average radium-226 is least in the Lower Main-Stem (1.3 €or 39 samples) while the San Juan Sub-Basin has the highest average radium-226 (4.2 for 50 samples). The hrcaltdown of the Upper blain Stem shows the average radium-226 in the San Pliguel-Dolores system (3.3 for 66 samples) to be twice as high as iii the Gumison system (1.7 ior 55 samples). It is also interesting to note tliair the average radium-226 concentration in sediments in tLe Lotier Main Stem is essencially identical to the average i. presented in Table 111 tor natural background sediments, and that the :. .. . averagc radium content 01 scdinents in Colorado River Basin (excluding those in Lake Mead) is slightly more than twice that found in natural i. background sediments. .,_..... I ,... . - .. . ..I ,,...., 1. I. . .- . . . .-I-,-

MAJOR SUB-BASINS OF THE COLORADO RIVER BASIN

COLORADO RIVER BASIN WATER QUALITY CONTROL PROJECT u. s. owl. OF HEALTH. EDUCATION. a WELFARE PUBLIC HEALTH SERVICE REQION Vlll DENVER. COLORADO

FIGURE 10 11

Radioactivity - Sediments for Major Sub-Basins of the Colorado River Basin

Radium-226 (ppc/g) Station Location Aug. 1960 March 1?61 Aug. 1S61

1. GREEN RIVER SUB-BASIN

82 * Little Snake River - - 1.2 83 ** White River - - 0. 9 0. 5 Lay Creek - 1.G 1.8 1.0 Lay Creek 1269 34* 0.9 I 1.5 Lay Creek - 15 2.0 2 Lay freek 4.0 6.9 3.9 3 Yampa River -< 1.0* - 1.0 4 Yampa River 1.2 1.2 0.8 5R Yampa River 1.1 0 3.0 5P Yampa River 0.8 0 - G Green River 0.8 .6 0.7 7R Green River -< 1.C* 1.0 0.9 7P Green River 0.8 - 8 Green River -< loo* - 0.6 17 Green River 0.99 0.6 0.9 18R Green River 2.3 1.2 1.7 18P Green River 1.5 1.8 0.9 25 Green River 1.8 1.2 1.0 .-.I SUB-BASIN .. - 2. UPPER MAIN-STEM i;'I. A. Gunnison River System

74 * Eagle River 1.3 75 ** Colorado River 1.5 76 * Roaring Fork River - - 1.2 9R Colcrado River .I 1.4 1.4 1.0 1: 9P Colorado Rivei- 2. 1. 1.8 1.2 ib 1OR Colorado River 1.5 1.9 1.2 1OP Colorado River 2.4 1.9 - 11R Colorado River 2.8 1.2 1.0 11P Colorado River 2.2 - 17 12 Colorado River 1.9 2.7 1.9 13R Colorado River 2.2 1.9 2.1 13P Colorado River 1.5 .8 78 ** Gunnison River - - .9 79 ** Tomichi Creek 1.2 1.2 1.1 72 Tomichi Creek 1.6 1.1 0. 9 71 Gunnison River 1.4 0.8 0.7 ......

:. , : -z, . .. 12

R32 Lain-224 Station Locat io2 Aug. 1960 March 1961 Aun. 1961

70 Gunnison River 1.0 0.7 0.7 69 Gunnison River I - 1.2 80 Uncomyahgre River 1.0 1.3 1.6 68R Gunnison River 1.0 1.0 0 68P Gunnison River -< 1.0" 1.0 0. 5 14 Gunnison River 1.0 ' 2.2 1.5 15 Colorado River 1.7 1.8 1.0 16 Colorado River

Bo San Miguel-Dolores River System

19 Colorado River 5.5 1.5 1.4 58R Dolores River 1.9 1.8 1.6 ! 58P Dolores River 2.5 1.8 1.9 5 9R Dolores River 2.9 284 1.4 5 9P Dolores River 189 5. 9 2.2 60 Dolores River 1.0 1.4 0.6 61R Dolores River 1.6 - 1.0

61P Dolores River 5.8 3.4 1.9 , 81 Jt.k San Miguel River 0 - 0.8 62R San Miguel River -< 1.0* 0.9 0. 7 62P San Miguel River 1.0 1.1 0. 9 63R San Miguel River 4.7 1.4 1.3 63P San Miguel River 11 1.5 1.9 64 San Miguel River 2.8 8. 7 2.0 65 San Miguel River 7.5 9. 9 11 66 Dolores River 4. 5 8.4 8.0 6 7R Dolores River 1.5 4.3 12 6 7P Dolores River 2.7 7'. 8 - 20 Dalores River 7.6 6.3 4. O , 21 . Colorado River 4.3 3.2 2.0 22 Colorado River 1.5 2.0 2.2 23 Colorado River 3.1 3.1 1.9 24 Colorado River 3.0 2.8 1.9 24.5 Colorado River 1.3 1.1

3. SAN JUAN SUB-AASIN

57 Animas River 1.3 1.4 1.1 .. 5 6R Animas River 8.6 46 2.6 56P Animas River 19 38 6.2 55R Animas River .G. 7 22 2.9 55P Animns River 3.3 5.8 - 54R Animas River 3.1 3.7 1.8 54P Animas River 2.9 4. 9 0.9 5 3R Animas River 2.2 3.6 2.0 f R3d 1uP.-226 ? Station Locat ion ;\uE, 1950 Wclrch 1961 AUR. 1961 ?i 4 '\ z 53P Animas River 2.5 3.9 1.3 N. 52R San Juan River 0.8 d.90 d 0.7 52P San Juan River -< 1.0:: 1.2 1.1 5 1R San Juan River 1.4 0. 7 0.8 51P San Juan River 1.0 - 0 50R San Juan River 1.2 0.8 0.9 SOP San Juan River 1.9 0 - 50.5 San Juan River - 0. 8 0.8 26 South Creek 2.6 7.5 2.0 27 South Creek 253* 0 7.6 28 San Juan River -< 1.0" 0.9 1.0 29 Montezutna Creek -< 1.0* 0.6 0.7 30 San Juan River -<< l.O* 1.3 1.1 31R San Juan River 1.7 1.7 0.4 31P San Juan River 1.8 2.9 0.8 34 Colorado River 1.3 1.3 1.7

4. LOWER MAIN-STEN SUB-BASIN

33 Moenicopi Wash 1.3 0.9 1.1 33.5 Moenko pi Wash - 0.6 1.2 38 Colorado River 0.9 0.9 1.1 39 La!ce Mohave 1.5 2.3 2.0 40 Lake Mohave 1.0 0.9 0.8 41 Colorado River 1.0 0.4 0.4 42 Lake Havasu 2.6 2.1 1.6 43 Lake Havasu 3.3 2.3 2.2 44 Lake Havasu 2.3 1.8 3.1 45 Colorado River 1.3 0 1.1 46 Colorado River 0. s 0.4 1.1 47 Colorado River 1.1 0.8 0.8 48 Colorado River 0.9 0.5 0. 9 49 Colorado River -c 1.0* 0 0. 5

*Not used in average **Sediment sample collected December 1961 14 TABLE IX Summary of Sediment Radioactivity for Major Sub-Easins of the Colorado River Basin

Radioactivity - (ppc/gm) Sub-Bas in Gross Alpha* Gross Beta* Radium-226

1. GREEN RIVER Average 11 42 1.9 Median 10 45 1.0 Range 4.0-575 19-83 1 0.6-126 Number of Samples 13 13 35

2. UPPER MAIN-STEM (Totql) Average 16 45 2.5 Median 12 42 1.8 Range 2.6-55 18-84 0.5-17 Number of Samples 41 41 121

A. Upper Main-Stem (Gunnison River System) hve rage 9.3 42 1.7 Median 7;a 35 1.0 Range 3.1-19 18-84 0.5-17 Number of Samples 19 19 55

B. Upper Main-Stem (San Miguel-Delures System) Average 23 47 3.3 Median 20 43 2.6 Range 4.0-55 25-74 0.6-12 Number of Samples 22 22 66

3. SAN JUAN Average 16 59 4.2 Median 12 45 1.4 i Range 1.4-125) 19-1310 0.7-253 Number of Samples 22 21 60 :

'r 4. LOVER PWIN-STEM i (Excluding Lake Mead) Avc rag e 7.5 33 1.3 Pledian 5.1 29 1.1 Range 1 .2-22 14-68 0.4-3.3 Number of Samples 13 13 38 t i Average of all Colorado River Basin Sediments Average 13 44 2.4 j Ned ian 10 43 1.4 Range 1.2-1255 14-1310 0.4 -25 3 Number of Samples 89 88 254

*Gross activity determined for August 1960 Survey only 15

LAKE MEAD SURVEYS A. INTRODUCTION

The preceding diacussion has shown the distribution of radioactivity in sediments of the Colorado River Basin. Such radioactivity has resulted in,largepart fron the discharge over a number of years of waste ore solids from the uranium mills in the Basin.

Lake Mead, impounded by Hoover Dam, has trapped almost all of the transported sediment load of the Colorado Ri-Jer Basin. Therefore it is ex- pected that most of the radioactiviiy carried by sediments in Colorado River water has been deposited within tne confines of Lake Mead and remains <.Alere indefinitely. Initially the majority of this load settled in the Uppt- Lake some 70 to 80 milec above Hoover Cam. In subso,.quent years the sedimen s gradually move closer to Haover Dan;,

Lake Mead serves as the domestic water supply for the nearby com- munities of Lad Vzgas, Boulder City, and Henderson, Nevada. Downstream from Hoover Dam are large diversLons for irrigation and municipal use in southern California, southeastcrn Arizona and Mexico.

B. HYDROLCGS AN:C LIMN(3LOSY OF LAKE MEAD

Hoover Dam began impounding the waters of the Colorado River to form Lake Mead, on Februiry 1, 1935. The original maximum capacity of Lake Mead was 32,471,000 azre-fect, including dead storage. Accumulation of sediment in the reservoir had reduced tSe maximum capacity by 1960 to approximately 30 million acre-feet. Sediment is deposited at an average rate of 175,000,003 tons per year which reduces the Lake capacity by more than 100,000 acre-feet annually. Lake Mead may store in excess of two years' equivalent of runoff of the Colorado and Virgin Rivers. The latter have a combined average annual flow reaching Lake Mead of 12.6 million acre-feet per year over the period of record f 11,12,13)

At the time cif the Coloradc River Basin Project survey of Lake Mead in , the Lake had a water surface elevation of 1,169 feet, a useable content of nearly 20 million acre-feet, a surface area of 195 square miles, and a maximum depth of approximately 420 feet. The profile of the Lake is shown in Figure 11.

Circu1a:ion currents found in Lake Mead follow more or less regular season pacterns and are caused by differences in water density in the vertical plane. These differences are due directly to variations in temperature, salinity and sllspended sediment content of lake water. Turbidity currents, which are actually densiLy currents containing high concentration of suspended sediment,are always present near the upper end of the Lake in the vicinity of Pierce Ferry but these flows rarely are sustained over the entire length of the lake. When Chese currents reach the dam, a rapid rise in water-sediment interface forms immediately upstream of the dam (12).

During winter the inflowing Colorado River water is of greater density than the water in the reservoir, due to lower temperature and greater salinity and hence, flows along the bottom. The spring runoff, due 0 llR61N t CAMYON a W T

8 EAST POINT * L: 0 a I&

W 0 owU

'IR61N mS1N 2 P

K W '> E .." *% \ .: i

16 ., to its low salinity, flows out over the lake water. In surmer, with in- creasing salinity of inflow, the downlake spread of river water occurs as an interflow about 80 feet below the surface. In the fali during which season the second sediment survey of Lake Mead was conducted, the decreasing temperature of the inflowing rivet water causes it to sink to greater depths as the season progresses. At this time, there is downlake flow along the bottom to the vicinity of Iceberg Canyon and Sandy Point. However, as denser lake water is encounteied at the greater depths, there is likely a flow spreading horizontally downla!ce to Virgin Canyon which further slopes gradu- ally toward the surface. Co:icurrently, two large cellular circulations, one producing uplake mcvement of surface water and the other producing uplake movement of bottom warer, exist in the autumn above the Virgin Basin. (12,13). Thus, during the second Luke survey, bottom sediment down to about Iceberg Canyon was likely in contact with recent inflow, while the interface below this point to near Virgin Basin was in contact with an uplclke flow of water, which had been impounded fram a previous time.

Cl. CONDUCT OF LAKE MEAD SURVEYS , Four separate radioactivity surveys have been conducted in Lake Mead. The first, third and fourth surveys on Lake Mead correspond in time to the three Basin-wide studies of August 1960, March 1961, and August 1961, and may be considered as part of these studies. Because of time and equipment dA limitations, adequate areal cclverage of the lake was not obtained by this 4 sampling program. 4 ,. . b d The secor,d Lake Mead survey was undertaken during the U. S. Bureau 3 of Reclamation's annual survey of the Lake on October 24-28, 1960, and provided mcjre comprehensive data on radioactivity of both sediments and ? waters. The U. S. Bureau of heclamation provided Colorado River Project

' $ .,. personnel with boat transportation and operatcr facilities on the October i 24-28, 1960 stlrvey when it was necessary to sample in the main part of the lake. I A 1200 to 20G0 cc Kemei-er-type sampler was used to obtain all deep- i water sediment samples. Ii ski.ff, normally towed by the main boat, provided 11 access for sampling shallow wacer at the head ends of the reservoir the in on f Colorado River and also on the Virgin River. At these locations, sediment .. and, in additim, water samples were cci?ected by hand. All sediments from both deep and shallow :,atcrs were obtained from the top layers of water - c sediment interface. Stdimerits were ccllected in one pint glass jars.

During the October 1950 la..e survey, water samples were also collected. These were taken by a Kemerer-cype sampler from the lake surface and the liquid-salid inrerface ic? investigate possible leaching of Ra-226 and uranium elements from the bottom sedineriis to overlying waters. Water samples were collected in one-quart ?clpcthylene bottlcs.

Table X p.:esents a tdrief descriptiun of all Lakc Picad sampling stations and Figure 12 gives a nap 02 the lccation of each sampling station. In most cases, samples were bbt-ained cvcr the original channel of the river. Additional comments conceming a Lcw of the stations are included as follows: 17

TABLE X Lake Nead Sediment Samplinn Locations Octsber 1960

Station No. Des P- r i p t ion

1. October. 1960 Survev

YM-1 Emcry Falls LM-2 Iceberg Canyon LM- 3 Sandy Point LM-4 Virgin Canyon Lll-5 East Point L14- 5 Boulder Canyon LM- 7 I!oover Dam LI4-8 The Marrows i UI-9 Ove r ton LFI- 10 Virgin Narrows LM-11 Henderson Intake

2. August 13G0, March 6 Au~usL:1961 Surveys

I 36a Colorado River at head GE Lake Mead 36b Just above Pierce Ferry 36c Midlaltc opposite Pierce Ferry 36d Midway between Pierce Ferry 6 Grand Wash 36e Main Channel opposite Grand !*lash $' -. e,. . 3 7a Nidway between Sandy Point ti Iceburg Reef 37b Plidway between Sandy Point & Virgin Canyon

35a Near mouth of Las Vegas !.lash 35b Upper end cf Las Vegas Boat Harbor 35c Las Vczas Bay opposite Gypsur~~Wash 35d Las Vegas Bay opposite Government Wash OOVER DAM AUG: 1960-AUGl 1961 c 18

LM-1. Emory Falls: This location was approximately 0.5 miles above the head of the reservoir at thc time of the survey. Water was sampled near the center of the stream and sediment was collected near the left bank.

LM-5. East Point: The measured depth at this point was somewhat less than the depth at the ncxt upstream lwation. Therefore, the sediment sample vias apparently not talccn over the original channel of the river.

LM-8, the Narrows: SaEples were collected near the west shore of the wide, shallow basin at the present mocth of the Virgin River. :.The Narrows:' is a constriction in the river channel immediately below this basin. I 1' LM-10, Virgin Narrow: This location was downstream of the lower limit of heavy sediment deposits in the bverton Arm. The sampling device intercepted a hard surface OK rock deposit at a depth of 275 feet and sub- sequently a sediment sat,ple was not collected.

LN-7. Hoover Dam t?d LM-11, Henderson Intake: Mechanical failure of the vinch used for lowt>ring and raising the sampling device necessi- tated poscponement of the sample collection at these two locations. Depths to the interface at both locations were not reported. The Henderson Water I Intake is located on the east side of Saddle Island in Boulder Basin.

I All uranium and a portion of the Ra-226 analyses were performed by the Project Laboratory. Gross radioactivity of the sediment samples was determined at the R. A. Taft Sanitary Engineering Center at Cincinnati, Ohio, ,The remainder of the radium0226 analyses were performed by a private labora- tory.

De PRESENTATION OF RESULTS

Water-Radium concentrations in the water samples collected during the October 196'3 Lake Mead Survey are presented in Appendix C.

Sediment-Table XI presents the data obtained on all sediments collected in Lake Mead. Table XI1 presents a summary of these data. It is seen fron Table XI1 ,hat the average radium content of all sediments collected in Lake Mead is slightly more than two and one-half times the natural radium content of unpolluired sediments. The sediments collected during the comprehensive October 1960 survey have an average radium content almost four times natuial backpround concentrations.

From Table XI it is interesting to note that there appears to be a progressive decrease in radium content of sediment from the headwaters of Lakc Mead to Hoover Dam (Uf-I. through LM-7). Also, Station LM-8 sediment radium is very low indicating natural sediment entering Lake Mead from the Virgin River. Q.;: .

.' .

19

L. ,4 . ' '5. TABLE XI

Radioactivity of Lake Mead Sediments

Radium-226 -(uu/gm) Station Aug. 1960 Oct. 1960 Mar. 1961 Aug. 1961

MAIN LAKE .. ,5. - 4.1 0 . f LM- 1 36a 1.3 - 0 b 2.6 - 2.9 C 4.6 - 1.8 ..A ' d 2.2 - 3.0 e 5.5 - 2.3

LM-2 4. s 3 7a -

LM-3 3.8 37b -

LM-4 5.0 5 4.0 6 4.2 7 3.9

OVERTON ARM LM-8 - -< 1.0* 9 - 3.6

LAS VEGAS BAY

.., 35a 1.6 1.2 '0 2.3 1.8 C 1.8 1.9 d 2.2 0.5

LM-11 - 2.9 * Not used in average ..*.

20

TABLE XI1 Suc.marv of Lake Mead Sediment Radioac tfvitv Radioactivity - (upc!P;rn) Gross Alpha Cross Beta Radium -226 e-' Ave rag e 16 55 2.9 Range 7.0 - 32 21 - 70 0.5 - 5.5 Number of Samples 21 10 38

RADIUM-226 TO GROSS ALPZA RATIOS

The determination of radium-226 involves quite lengthy radio- chemical and cotnting procedures in vrdcr to obtain the desired result. In contrast, gross radioactivity decerminations can be acconplished in a fraction of the cime required Lor a radium analysis. Oftentimes, a gross radioactivity analysis has becn regarded as i3 crude device without any real meaning. Gross alpha determinations hovever have been found to be sensitive indicators of pollution Irum uranium mills. In all types of samples a very consistent relationship between radium-226 and gross alpha has been found.

Table XI11 presents the radiun-to-gross alpha ratios for the sedi- ment samples collected in the Colorado River Basin.

From this table it is seen that there is a relatively narrc.., range in the average radium-226 tc) gross alpha ratio for the various cypes of sediments encountered in the Colorado River Basin. This range LS 0.16 to 0.26. The avcrage of all samples for which both gross alpha and radium- 226 analyses were performed (176 samples) indicates a radium conLent of 21% of the gross alpha activity. 8 SLatistical analysis of these data show that tile standard deviation is 0.035. In odicr words, 95% oE all sediment samples in the Colorado River Basin would oe expected to have a radium to gross 21pha ratio be- tween 0.14 and 0.28. SUFfN;'*RY ANE DISCUSSION OF DATA

The preceding pcrtrvn of this rcpor t has presented detailed tables of results of radit~t-225, gross zlpli~ and griiss bcLa determinations on sediments collected throughout Lhe C-I -rcidoRiver Basin during August and October 1960, and during Flarcb a22 *!i):..ct of 19.51. A final surrnary of these data is percintnt at th point.

Spcciiically, 49 'sainplcs rcl.iescatjng 20 different sampling stations wre collected in locations where thc sediment was not influcnced by uranium mining and milling acrivity. Thcsc locations have been referred to as background Ixatiirns. (111 of tile samples were analyzed fur radrum- 226, while 14 of then wcrc analyzed Lor gross alpha and gross beta activity. These data shoued an i3ve:-qce radium content of 1.1 ppc/gn with a range of 0.6 - 2.1 ppc/gm. 21 TABLE XI11 Radium-226 - Gross Alpha Ratios Colorado River Basin Sediments

Table No. Sediment Type Ra-2261Gross Alpha

I1 Background Locations Average 0.17 Range 0.06-0.45 Number of Samples 17

IV Main-Stem Colorado River Average o. 22 Range 0.05-0.48 Number 30

VI Immediately Downs tresin Average 0.20 From Uranium Mills Range 0.07-0.63 Number of Samples 23

VI11 Major Sub-Basins

I. Green River Sub-Basin Average 0.16 Range 0.06-0.31 Ncmber of Samples 13 2. Upper PZain-Stem Sub-Basin a. Gunnison River System Av e r age 0.19 Range 0.07-0.43 Number of Samples 18

b. San Miguel-Dolores River System Average 0.19 Range 0.07=0.45 Number of Samples 21

3. San Juan Sub-Basin Average 0.23 Range 0.05-0.63 Number of Samples 22

4. Lower Main Stem Average 0.26 Sub-Bas in Range 0.11-0.48 Number of Samples 12

XI1 Lake Mead Sediments Average 0.22 Range 0.10-0.41 Number of Samples 20

ALL COLOEUDO RIVER BASIN Average 0.21 SEDIMENTS Range 0.05-0.63 Number of Samples 176

I. I...... 22

For the sediment surveys reported here, 254 samples representing 121 different sampling stations were -ollected in all parts of the Colorado i River Basin. In order to obtain an over-all view of the data, Tsblc :.lV Il, 't presents a general summary table.

TABLE XIV Radium-226 in Colorado River Basin Sediments

Concentration Multiples of Number of Percent of ~uc/nm Background Samples Totals

< 1.1 <1 95 38 31.1-5 1'50 4.5 132 52 5-10 4.5 to 9 15 6 10 >9 -12 -4 2 54 100

Average of All Sediments: 2.4 pyc/grn 1 .' BacIrground Sediments: 1.1 ppc/gm

Prom Table XIV it is seen that about 40 percent cF sediments collected in the basin were equal- to natural background concentrations of radium, vhilc! half of the sampLcs were between 1 and 4.5 timcs bac!:ground levels. Ten percent of the samples were greater than 4.5 times background.

The data have shotm,among ocher things, that Lake Mead has been essentially the final restins place for the radium contaminated sediments of the Basin. With the closure of Glen Canyon Dam upstream, Lake Powell will then become the Linal resting place for Suture radkum contauinated sediments. The data also sliow that a snull frac-;on of the contaminated

sediment has aL ._ .& --,A passed through Lake t

With regard to the effects of hydrology on the deposition and accumulation of radium-bearing sediment the data yield some other interesting observations. Daily hydrographs have been presented earlier for three typical locations in tile Upper Colorado River Bzsin. As pointed out, two of the surveys were conducted soon after subsidence of flood flows and onc just before the spring snow-melts. Earlier studies on the Animas(8) showed that thc radium content of sediments increased considerably dui.i.ng extended periods of low flow, due to accumulation of mill solids, t hicii [*.ee picked tip ar.c txair..;ltul tcTd lurthe-r do: :lSCi-l*anT .:.I: during high Glow periods. In 0r-k- :T ----'-d. - ~rd~ 3dditio;;al itC^r?i~ion 23 on the accumulation of radium in sedirncnts the data from the March 1961 Basin-widc survey wre averagcd and compared to averages of the data from the two August survcyu. Thcse arc discussed below.

Sedicents collccted in locations unaffected by uranium mining and milling activity stiowed an average radrum-226 content of 1.21 ppc/gm for the March 19G1 survey ccmparcd to 1.25 lvc/gm for che two August surveys. This is an interesting compai.ison and is what would be generally expected; namely, that in natural background locations the radlum content of the sediment should remain coastant and unaffected by any changes in flow patterns of the river.

Sediments collected immediately dokinstream from uranium mills showed an average radium-226 content of 8.73 ppc/gm for the March 1961 survey and an average of 3.24 ior the two August surveys. These data clearly show the accumulation of radIum in sediments during extended low flol) periods.

Another interesting comparison is obtained when the data from samples collected only on the main-stem Colorado River are trcatcd in the above man- ner. These data show an average radium contcnt of 1.71 ppc/grn for the March 1961 survey and an average of 1.55 ppc/gm for thc two August surveys. These data tend to indicate that iil a very large river such as the Colorado the amount of scour and transport of bottom sediment even during low flow periods in most cases is signif icmt enough to prohibit much accumulation. Also the accumulation oi radium-bearing ore sclids is probably tmsKed by thc tremendous volurncs of other sediment material. In a srnallzr river the ac- cumulation might be mJre readily apparent.

When all sediments other than natural bac!:ground sediments are considered, as a whole, the data shov an average radium-226 content of 4.19 ppg/gm for the Piarch 1961 survey and an average of 2.22 ppc/gm for the two Ciugus t surveys.

The values of 8.73 ppc/g and 4.19 ppc/gm are largely influenced by a very few samples taken from dry washes iunediately below several uranium inills .

Excluding these: the data show a great reduction of sediment radium content since 1956(7). This is a result of improved waste disposal practices at the uranium mills in the Basin.

The data also show that the river sediments can be useful indicators of radiological contaminatica. Such saiilples accu-r,ulate radioactlvity and yield inlormation uti conditions for an extended period of tine sut- sequent tc. collcction. \later sairtples cti the other hand yield inLormation on instantaneous values at Lime cf collcct;.un.

It vas rncntioned earlier that both riZfle and pool samples were collectcd from varims locations to otscrve

Observation of the riffle and pool data shows that while some of the pool sediment contained aore radium than did riffle sediment, the data are generally not significantly difFcrent at a given location. In some cases the riff le sediment contained more radium than pool sediment. At two locations the pool sediment coprained quite a bit more radium than did riffle sediment (Stations 56, and 63, Table VIII).

RADIUPl LEACHABILITY

I fhe quantity of radium-225 rJhLch can be leached from uranium mill 1 waste soiids and rivcr sedimenc material by overlying waters is governed :' , by a complex combination of chemical and pliysical factors. A brief dis- cussion of results of recent laboratory sixdies on this subject is presented below. (lo) The results showed that - 1. Significant quantities of iadium in terms of current caximum permissible concentrations can be leached from uranium mill waste solids and from river sediments.

2. The amount of radian which is leached from uranium waste solids and rivet sediments is primarily governed by the liquid Lo solid ratio (mi/gm) as shown by distilled water-leaching tests. The effect is greater for uranium waste solids than for river sediments. In the case of uranium wclstc svlids the account of radium leached frorr a given quantity of salids versus the volume of leaching liquid is seen to follow an "S' shaped curve. Such a curve is shawn in trppcndix A. At low liquid volumes (10 ml - 30 m!) the amount of radium leached a. .3. is practical !y independent of the quantity of sol ids, the amount leached being governed by the amount of barium sulfate precipitati-Jntaking place.

'.'- 3. There appears to be essenrialiv--nc time dependence e after 15 minutes on the arnoirnt of radium leached from uranium mill waste sclids and river sediments, so far as laboratory experiments arc concerned. These effects most probably have a dilferent time relation in a rlvcr.

4. The diffusion of radium fron the interior to the surface of particles was found to be insignificant and unimpcr'nnt. This was true whether the solids were stored in a dry conditim or in a wet environ- menc. This indicated thc radium is only leached from the surface cf such part?.cles and is an imporLanr finding in terms of 'storage ' of samples in a ._- reservoir or in a river ljdring low flows. 25

5. For a given liquid-solid ratio, repetitive leachings of solids with distilled water showed essentially no additional radium being leached after two con- secutive leachings.

6. The amount of radium which is leached with distilled water is small compared to that which can be leached with vigorous leaching agents such as 0.01 M barium chloride solutions.

7. Of the cations, H+, Na+, K+, Psi-'-, Cau, Sr"'- , and Ba* at I.0'2M, only barium exerts a significant effect on the amount of radium leached fr.Jm river sediments, with considerable amounts being leached by barium. Barium concentrations in the range which would be expected to be encountered in natural river waters of the West leach no norc radium than distilled water.

8. The chemical characteristics of natural river waters from represmtative locations in the Colorado PlaLeau have nc diffcrcnt eifect on the leachability of radium than distilled water. In fact, because of high sul- fate concentrations and precipitation of barium sulfate, the amount of radium leached from uranium waste solids a. by natural wdcers is significantly less than that leached by disti1.led water.

9. The effect of temperature in ihe range 3O to 25O C and degree of agitation, as long as the solids are intimately mixed with the leaching liquid, arc not

I important parameters in the amount of radium leached.

A more detailed discussion of the rcsults of the laboratory re- search is given in Appendix A.

A brief discussion is given below of the effect of the discharge into the water environmcnt of radium-bearing waste solids and the behavior of radium in this water environmcnt.

Upon discharge into a river of uranium mill waste solids which contain appreciable quantities of radiun, there will be an imediate leaching of some radium with an almost IKmerliate co-precipitation of this radium as barium-radiun sulfate. This comes about because of the relatively high sulfate content of the river water, the sulfates re- leased from the solids, and the insolubility of barium sulfate x the (Ksp=l 10 -lo). Of radium left in solution, a large parr will be i adsorbed onto the river sediment and a portion will also probably be readsorbed back onto the mill solids, The result of thcse reactions is that only a small amount of the radium originally dissolved remains in solution. 26

A short c istance belor. t!ie mill iischarge the bottom seciiinent material in the riber rill consist of a mixture oi natui-a1 ~iverscdiment 1.hich coiitain radium, anti t.aste ore solids also containiiip, racium. Assuming i: peiiod of 106, flow, the bulk OL the stream sediment till remain unoistuzbed on the bottom t,ith only the very iim material being transported in solution. For a lor? €lot associated ~ithnonturbulent celocitics, it is reasonable to expect the suspended solids concentration to be very 101 at the surface aiic increasing to a maximum at the liquic-solii inter'-acc.

The amount of leaching taking place :-tom che bottom sediment during these periods 0;. lot, 2101. t:ill vary depending on particular circumstances. It is low relative to cther conZitions u;' tuzbulent i101 anti scour tiescribed beloti. Because of the small amount 0.: suspendcd solics transported during lot; r-Clot:s, it is likelv that.sn equilibrium \.ill exist bett.c>en the raLium in solution and the radium content of the suspcilded sediment. A short distance belot; a mill, however, tilt rclativc proportions of line orc solids versus the true liver sediment transportcd \.ill in 1aii;e III~!JS~J~'C'dctt.riaiiie the amount 0,' radium leached 2rom the mixture oi solids.

With the advent oL spring snoti nilts arid resulting high river .?lois, the bottom sediment is thoroughly .iii:;ec~ ~ 2ickc-G i?p ani. transporte6 iurthcl do\.nstream. At this tine appreciable amounts of rsiiurn arc leached frm the transported solids. Tilis has'b<.cn louni- to bc truc from the Aninas River ant: other studies. Tiiere is also at this tine aiuthcr re-distribution 01 the radium betreen ail1 solius anil ri*;cr secimcnts. hs thc hicii 21m.s subsice ani 101; flois again set in, a rcpeat process ?:I a lcsscr scale, of tile previous lovj flow conditions occurs.

With each subsequent high IC<.concit ion, mixing snd transportation of sediments dot ilstrc~m,thc amount OL iac'ibm *.liich is lexheu becomcs progressively less. Eventually a situat1Qi-i is rc*sclwd in \ hich t:ie maximum amount of radium has bccn leached, 11th littlc lurtlitr lr 3-hing ~romtlw transported solids. With discil;ir~;c~9; the river into a large reservoir, the amount of lcaching i.hich takcs phcc in the rcscrvoir scc'imcnts is probably negligible, provided the inconing solids havc bccri transportcd iar cnough to have had the maximum amount oi racium lcachcti Lron thcn.

The above discussion has ncglcctci sevcral lactors Ihich may be of significance in the behavior of raciiJm Lc J river. These Cactors are (1) the uptakc of radium by the aquatic lilc in the river, algae, insects, fish, t.ater r,ceds, etc., (2) use of thc iivi'r ioi :irig.Ition, (3) number of uranium mills ciisc~largingcriluents into the river, ani (4) other lactors depending on local conuiiions alii ciriunstances.

SUMMARY

The data presented in this rcrort hmc. provided i:.'ornation concerning the radium content 01 bottom sediment material throuehou- ;he Cclorado River Basin. The data on scdiments from locations unaffected by any uranilim mining and milling activity present usetul information regarding natural background con- centrations of iaciium in such scdimtnt. 27

On the basis of these natural background radium-226 dcterrninations any sediments in the .Basin \rhich shou an average radium content signiiicantly greater tnan 1.5 ppg/gm can be considered to be c,qntaminated either as a re- sult o< taste discharges from uranium illills or from mining operations.

Assuming that significant discharges 02 ilaste ore tailinzs into the t:aters oC the Basin havc ceased and that uaste ore irom existing and abandoned tailings piles is prevented il-om reachins these \.3ters, it is reasonable to expect that the sediments oE the Basin rill become stabilized in their radium content at the usual aatural level. Once such stabilization is reached sediments shoving higher radium content can otily result from pollution Q .. .? activities. By routine monitoring in selected locatioas sutiden increases in 1 sediment radium can Le noted anti the source readily dctcrmined. .-..j FUTURE \'ORK DESIRED

In conjunction w.:.th inatcrinl presentcc! in this ieport there are several areas in vhich Zurther iiilormation i.ould be tiesirable. These areas -. !., are discussed belo\,. f. Ii 'I. llith regard to the Lake Plead se.cimeuts it ~ouldbe desirable to obtain iniormation re2z-r-diiiS the ratiLLim content oE lake sc-criments prior to uranium milling activity in the Basin. Dur.ing the period December 1947 to April 1249 ,. the U. S. Geological Survey collected core samples oT Lake E4ed sec'iment deposited betvcm and Initial coIitact teen made i:ich the --. 1935 1949. has ;E' .- :..- , U.S.G.S. on the possibility of obtaining portions of thcse carly sedimezts bo ior iadium analyses.

As 3 follo. --up it tould ;~lsoseein desirable to obtain corc samples of sediment deposited siirce 1949 ia order to cictcrminp radium content of these sediments since the adve;lt 0; intensive uranium mining and milling in the Bas in. , Another aspect i.hich deserves spc.ci-?l consiieration is a study 0; the distribution oLC dissolved raciiun in river ~atcr,raeidm in transported (or suspended) scCimeil'i, bottom scdiment rnatci-i-tl and aquatic biota. This could be done ot J particular loration by ohservinz the radium distribution among these phases over 3 period oi time. Such J study :7ulc! yield additional information on the rate 0.' racium iil the later environment.

I :'.I ...I REFERENCES-

1. Vaste Guide for the Uranium Plillir.;? Incustry, E. C. Tsivoglou, . and R. L. O'Conncll, U. S. Public Health Service, Robert A:Taft Sar,itary Eazinwring Ccntci, Cincinrati, Oiiio (1;IGZ).

,. 2. Lntroductorv Nuc lear PhvSicS: D. Holiday, John Lilcy 61 Sons, ._-.. Iric., NCT York, N. Y. (1'359).

3. Proccss alii Lmte C'iaractvristics at Sciected Ur2nium Mills, I Field Operations Scxtion, U. S. Public Health Sc'rbicc, Robert A. Tale Sanitary Engincering Ccnter, Cincinnati, Ohio (1962). 4. Maximum Pcrmissiblc Body BurcenF- and Maximum Permissible Con- c-t.itions of Radionuclircls in Air anc b.:atcr Lor Occupatirral EXPOSUXC,NCRP, National Bureau oL Standards, Handboolc 65, ! Lashington, D. C. (Junc lY59). e- ,. . L', 5. International Cormission on Radiological Protection, ICRP Part 2. Report or Committee I1 on Permissible Cose for Internal Radiation, Pcrgomon Press, Lonclon (1555)).

I 0. Rcport i)f Survry of contamination of Surface baters by Uranium Rccovcrv Plants, E. C. Tsivoglou, A. F. Bartsch, D. A. Holaday, D. E. Rushing, U. S. Public Health Service, Robcrt A. TaEt Sanitary Engineering Center, Cincinnati, Ohio ().

7. Efiects 0; Uranim Ore ReLCincry Ihstes on ReceivinR Waters, Scwage nnu Industrial Kastcs, 30, No. 3, 1012-1027, (August 1958).

d. Survcy of Interstate PJllution of the Anirnas River, Colorado- NL-\ Mesz, E. C. Tsivoglou, et al, U. S. Public Health Service, Robert A. TaEt Ecgincering Centcr, Cincinnati, Ohio ().

9. Survcv 01 Interstatc Pollutioti or chc Animas River, Colorado- Nci MCXACO. Part I1 l',')? Surveys, E. C. Tsivoglou, et al, U. S. Fublic Health Service, Robcrt A. TJft Sanitary Engineering Center, Cincinnati, Ohio (January 15'60).

10. The Leachability of Raiiurn-226 from Uranium Mili kastes Solids ancl River ScGiments, S. L. Shearcr, Ph. D., Disscr- tation, Univcisity or Visconsin, (i962).

11. SurLacc \..ter Supply of the Unitca States. 1959, Part 9, Colorado River Basill.- U. S. Geological Survey, Iiater Supply Piper 1633.

12. First Fourtecn Years of Lake Miad, Haroli E. Thomas, U. S. Gcnlogical Survcy, Circular 346: Kashington, D. C. (1954).

13. Comprehcinsivc Survcy of Scdirnentat ion in Lake Mead, 1948-49, t!. 0. Smith, C. P. Vettcr, G. B. Cumminp, et al, U. S. Gco- logical Surwy, PrDfcssiondl Paper 295, b.ashington, D. C. (1954). 29

APPENDIX A

LABORATORY STUDIES ON RADIUM LEACHABILITY

The 2olloi8ing ciscussion prcscntr; a surisry of thc salient findings of the leachability studies.

It 13s sho1.m Lor uranium lsstc solids and Lor river sediments that an equilibrium IPS reachcc, iapidly tith rcg3rd to the amount of radium leached from the solics as a iunction 0; tine. ALter about Cifteen minutes no additional radium \.as lcached up to a period OF six days. Figure A-1 shorls a typical curve.

It was also sh0v.m through scvcl-a1 tcsts that radium is more likely to be leached Srom urairium 1:aste solicis than Crom natural uranium ore. This is brought about :by tire processes r.ihich take place during extraction of uranium lroin tile ore. In this.extrirction it is rcasonable to expect that, as a result oi.thc* sulfuric acie lc'ach ti& steps, some radium is also solubiJ.ized froin thc o;e. Later in thc mill proc(.ss this radium is re- precipitated and ends up in the i aste s3liiis and is subject to leacning.

One of thc most sigaiiicant finclings 0.: this research 1 as the e''.'.&Lect 02 liquid-to-solid ratio oil the leachability oi radium. It \.as found that for a given quantity of solids r_l plot of the amount of roiium leached versus volume 02 1t.aching liquid desciibcit an "S" shaped curve v;ith three distinct regions. Such a curve is shovn in Figvre A-2. At lot: liquiC: volumes the amount 02 rabium leacned remilined constant with increase of leaching volume. Beyond a certain volume, small increases in volume re- sulted in large amounts 02 radium being lcachrod. A thirii tcgioqexisted v:lwre large increases io volurw iesulted in vcry little additional radium being leached. In this third region, the amount 0: radium i:hich can be leached is apparently a maximum and is primarily governed by the quantity .' of solids availablc or the total radiun reservoir. In the 1ov;est liquid volume range, the amount of radium leachcd ws iiiicpcndent of the quantity or' solids present. i

In ,Lact, it \;as shorm by special tcsts that, For the particular solids studied, the amount oE raiium tvhich could exist in solution at lov leaching volumes was severely limiting apd go;:erncd alrnost entircly by the sulfate present in solution. This is brought about by the Fact that the waste solids had associated viLh them, as il result of the mill proccss, large quantities of sulfate. This stiliatc could be c2:Sily soluLilizei by small quantities oi liquii anC because of the trace amounts 0:: barium present, prccipitation of barium sulfate resulted. Along ~iththis radium (:as co-precipitated *..it:] the barium sulfate. This derno:;stratcvd by aiiing a knom mount ~f standard radium spike to a ssniplc containin:; i:aste solic:a and distilled vater an& leach- ing Cor a perioti 0 tine. These tcsts shoi.ed that ihcr.. radium vas added prior to leaching and filtration, all of it ias lost as a result of co-precipitation with barium suliatc. When the radium \.as added to a leachate after Ciltratinn, all of it was recovered.

Repctitive leaching tcsts shot;e!d a xapid decrease in thc amount of radium leached in conscctitive leachings Zollotjing an initial leaching. The decrease tjas greater in the case of sancs-slime waste solids than Lor river sed ime n t s . 250

+ 0 2 200 r t t 0 g 150 0

IO0

50

LEACHING TIME IN OAYS -- CALCULATED LINE BASED ON DILUTION 4ND ASSUMING NO FURTHER LEACING AFTER ONE HOUR.

0 EXPERIMENTAL POINTS OBTAINED. 1.0047 GRAMS 976 UUC RADIUM 1000~~.DISTILLED WATER T 0 25.- 27-c 0 RADIUM LEACHED

d vs. VOLUME OF LEACHING LIQUID COLORADO RIVER BASIN 1 WATER QUALITY CONTROL PROJECT 12

IO

8

6

4

2

30

LEACHING VOLUME -ml. 30

Aitotiwr important LiiiJiilg o.f Lhc rcsc-arch \.as chat tlw role oi dilfusion is insigniiicant in ttic lc+acliability 0: raiium irom uranium 1.astc solids ani from rivtr scrliiwnts. Prior tcork reportcd in the literature has siio1.m that iii'lusiorr 0:: radium ;rum the Liitcrior of partiilcs to the surlace \,as the m;rjor Lactor iri the anrount of radium lcacht-d from iiatui-a1 ores and 2rom spcciclil ly prr,parid salts v,iiich coritainei radium. It !.as sho\:ii in this vork tlrnt storazc oi simples, aLtr-r repetitive leachings, eitl~crin a dry or tci: environment Tor ;I long periou of tiirrc resuited in no appreciable increase in the amoutkt of xadiuiii leached. Tiiis 1.3s true ior uranium %:aste solids as \,ell as .:'or ri:cr sediments. Figure A-3 s110i.s a typical c;livc oE r c pi' t i t iv e le a c h i ng p I us d i f f us io 11.

111 coajunction tlith ~hcditlusion cturiies it 13s imnd that ir' uranium mill wsce solids, v,hich hat bccn leached 3 nbmbtur of times 1:ith distilled I ater, LC~Csubscqwntly leachcd ~ith0.01 M barium chlosicrc, betibeen 30 anu 40 pcr cent of the.radicm bas leaclieci in a one hour leaching. Tests on river sediments indicated that one hour leachings with 0.01 M barium chloride solutions removed about 20 peitent of the radium.

Leaching tests comucted on river sccliaents using 0.01 M solutions of the corrmon iilorganic catiorls Pourlci in vcstel-n river vaters shcwed that barium t:as the only ioti 1tLich hacl any appreciable crfcct of the amaunt OT radium leached. Tnis clfect on tile amount oLr radiun leached increased in the order NaY, K*'-Lor elements ,*a column IA oL the Pcriodic Table and 8, .; + in the ordcr Mg-'--, Ca-'-'*, sl- , Ba-lT, for elenents it; column IIA of the Periodic Table. This is the eifcct idircti tould bc expected based on 'ihe exchange propt'rties OZ thcse cations 1ith iespcct to d cation like Ra"'.

The el'iect oL various concentrations oL barium chloride on the leachability oi radium was studied using river ScdLiacirtS as a test material. The results sho\,cd a linear relationship ill the- raiigc 1.5 x lo'* M to 10" M. Bclow thz arrocnt of rzdium LBached 1'3s arastically reduced. At a concc~lt~atiuuoi: N ttie aXoGi1t of radim ~caciied\.as not sig- nilicantly greatcr tlisn that lc>achtd 1.:: t:i uistrllcd r.ater. A $?ncentration of 10-4 barium c!lloi-:Ge rould be equivalent to 15 m,o,/l of Ba-';-, a con- centration not vcry likeli to cxisc in \r-s;ern riber :aters bccause ol' high sulfates.

Rcpctitivc leaching 07 a contclrnLaatc>S I i1.c.r scoisent \lit11 0.01 M barium cliloritlc solutions sho~cr'cl rapid oeLrerisc in tilc arr.ount of radium leached I jth a total oi 21 percent king leachcci in Lour succcssive hours.

Anothrr signifiLmc iinciing oi t:-*c rcscnrch s1iot.c.d that natural river waters had esscntiaily no uif crcnt elfci-:: on the 1eaLhing ol: radium tharr 1.ould be observed ~..ichdistilieG I ;Iter. Tills is especially true for river sedinL,nts. For urdi>iiim mill k,nStt' S:)li.os, ho\ ner; thc amount of radium leaclwa t+:ith the river Ltatr'rs !:as considerably lcss than 1-as iound t!ith uistil1r.d s:atcr lcaching. TI:lis \as due to the ,iig;ll sulfate present in the river I,atcrs ~hichcdused aduitloncll prCCLi.~tatiori oi barium-radium SulfiItc. 21

IS

IO

AFTER I1 DAYS AFTER 21 DAYS I FiORAGE!;yrRAGE -

0 .- *. i *. L 4 e

IOOYL DISTILLLO I SAMPLE NO. 3

> AFTER 21DLYS e DRY STORAGE -

C I 2 s

--3 SAMPLE NO. 4

RE PET1fl VE LEA C HlNG Uronlum Mlll Waste Solids COLORADO RIVER 8AStN OC 1 1 I 1 1 WATER OUALITY CONTROL I 2 s PROJECT NO. OF LEACHINGS

FIGURE A-3 31

It was .:hotn that grindin:: of solids to a particle size of minus 140 mesh resulted i;1 d slibilt but detectable increase in thc amount of

1 radium lcachcd in tile case oL uranium waste solids but essentially no increase in the case oi river sc~dirnc~~its. JI

I< Finally it toas shotjn that by r?oucing the temperature oi leaching from 2S0 to 30 C, ad by rcducing the shaking rate ta half, no appreciable difference in the quantity of radium ltachcd [as observti lor the uranium !.as te so lids.

i 32

APPENDIX B

The location and description of the various sampling stations established For the sediment samplin;: surveys \.ere as follovs:

Station Number

0.5 Lay Creek SO yards above Maybcll, Cola., uranium mill effluent \:.ash.

1 Mill eifluc-lit \:ash :elow Maybc-11, Colo., uranium mill. Sample ;f ;f i taken above Lay Creek, 200' bciloi; HiLiicay U. S. 40 culvert I? !.: 6.h miles cast raf Iqaybell, about 4 miles belot: the mill.

1.5 Lay Creek 500' bcloi: Maybell, Colo., uranium mill effluent \;ash.

2. Lay Clce~aboLc confluence i!ith Yampa RLvcr. Sample taken at bridge on cou~iiyroad about 1/4 nile abotre cotif luence with Yampa River.

3. Yampa River above Lc:y Creek. Sa~cpletaken near Jilnipcr Springs, Colorado. 5.0 miles from county rmc junction Y iih U. S. 40, 4.0 miles cast ui Ilaybcll.

4. Yampa Rivci belot. kiaybe11, Colorado. Sample taken at bridge on Colorado Route 31d (at Sunbclam) 6.2 miirs northeast OF junction iiith U. S. 40 at ilaybell, Colorado.

5. Yampa River near mouth. Sample talcen at FIantlc Lanch at Castle Park id Dinosaur National Monument; about L3 miles irom junction of U. S. 40 and ColJrado [>5.

6. Green River at Jenscn, Utah. Sample ta!ct>n from U. S. 40 highiiay bridge \:itli a Pcterscn dredge Liom mid-river.

Green River nea: Dutsli John; Utah. Sample talccn just above the roooen suspension britige on tcmporary Utah 41., about 1 mile above Flaming Gorge damsicc a1032 tlw north Lank or the river.

d. Green River at Ouray, Utah. Sample ta!;en at quarter points from Utah 33 higiiviay bridge.

9. Colorado Rivei- at Silt, Colo. Saoplc. ta!:en approximately 7 miles upstream 0.: the old Union CxrSiec Nuclear uranium mill; taltcn Lrom t1.o bridges vhicli span tto scpxrate channels of thc river. A pool sample vas co!.lectcd irom thc south channel bridge; a rifile sample \!as ta;:c+n I'rom thc north cliannc.1 bridge.

10. COlOr3dO River at RiEle, Colorsdo. SmpLc taken betvccn the old * and the nee Union Carbide Nuc lcar mills from the bridge on Colorado 13. ....,... ^..*_ . .. _*-

I:

: : I ,.-. 33

I Station ... -Number ' .. 11 Coloratio River belov Rifle, Colorado. Sample taken 3.3 miles dot,nstream from thc tlc~.!Union Cclrbicic Nuclear mill and 10 miles west 01 Riilcl at Rulison, Colorado; collected lrom the bridge ori a sice rcjad 1/4 mile Trm Hi,lnlay 6.

12 Colorado River at DeBeque, Colorado. Sample taken at the CeBeque 1 raw watur intake at the bridge ~n the old highr:ay through DeBeque.

13 Colorado River above Granc JuncLlon, Colorado. Sample taken at the 1 bridge on the county load near Clifcon, Colorado; G river miles

above the U. S. 5L' bridge. L

14 Gunnison Rivcr nea; moulh Jt Gi-anc Junction, Colorado. Sample taken 0.5 rni1c.s atckt- ttic tr.uutli 1ror.i the bridge near the AEC Operations Oflice. I 15 Cc,lorado Riycr below GranC Juqction. Sample tqken at the PHS Basic Data Stzticn at Loizi, Colciicldo; 2.3 miles south from the c rossroaus at Lma.

16 Colo,ado River at Kesti.ater, Utili. Samplc taken at the end of tlie roa6 which par-allcls the C&RG\! RR.

17 Greca Ri1,:i m:ar Green River, Utclh. Ssrr.?le taken from the U. S. 6-50 bridbc just eas; of Green Kiver, litan.

13 Green River belo\: Grzen giver, Utsh. Sample talwn just upstream oi Crystal Gcyscr; i, miles e3c.t cT Green Fiver, Utah on U. S. 6-50, turn rigiit e-I dirt road, proceed 6 miles to river. Thc pool sample \.as collected just upstream 0: Cryst.11 Geyser; the riffle was taken about 1,'s mile bv101.~ tlic geyser,

19 Colorado River above Cc,l~x.c'sRiver. Sarnple takctn 3.1 miles up- stream from Detjcy bridgr:. 011 Utah 123.

20 Dolores River near mouth. Safisle taken at tlie termination of the road from De\.ey bridge to the river: approximately 0.3 miles from the bridee..

21 Colorado Rivcbr belot, Ddlorcs River. Sample taken irom Dewy britigc on Utah 126 by orcd;:c.

22 Coloradc 1:ivcr kcirk; hlores Mivclr. Sarq.)lc\ talten 2-1/2 miles dowitstream from ik.,ej biidG\.. iron thc east bank.

23 Colorad9 River at bIoa5, Utn!i. Sample ta!r=.n from U. S. 160 highv:ay bridge 2 milts r est of Mc ab. 34

Station Number

24 Colorado Rivcr belof. Moab, Utah. Sainple taken along the east batik at the ciitiancc to thc cclnyuIi (Tlw Portal), about 2 miles below the URECO uranium mill.

24.5 Colorado River at Hite, Utah.

25 Grecn River at Mine;-a1 Canyon. Sd:nple tclkerl about 3'3 miles belot) Green Rivei, !Jcah. ProceeL DcJd Horse Point turnoff 9 miles north OE Moab on US IbO, go 14 miles and turn right to Mineral Canyon; 20 15 miles aw take right Lork 0.6 miles to tile rilrer baiik. Sample collected along the east tank.

26 South Creek above idanticello, Utali, MC uranium mill. Sample talce!i just ahogc mt!:iicipa? scvagc treatment plant cischarge. ,

27 South Creek bclw ilonticello, Utah AEC uranium mill. Sample taken about 1.0 mile belov the discharge from the mill on T. M. Scucnson propI2rey.

23 San Juan River abovc Morltczuma Creel: near Aricth, Utah. Proceed Utah 262, 21 rnilcas to end of pavement. Coltci.nue 4.0 miles through oil liclds to thca bridge ovci the San Juan River. Sample taken by dredge Lrom tne bridge.

23 Montezurna Creek mar confluence ~tithSnn Juan River; Utah 262 cmsses Monte-zuma Crerk 3.3 milcs be€ore tile cri6 of tile pavement, 20.0 miles lrolil junction titi1 Utah 47. Sample collected about 1000' upstrcm fiom the oiioge. The stream ras dry at the time Oi the August 1960 survey.

30 San Juan Rivcr i*bme Flcxican Hat, Utah. SampLc taken neat the USGS weather station.

31 San Juan River bclw. Xcxiian Hat, Utah. Sample taken about 1/2 milc dowistream irzs the urailiun mill cbi:luent dischclrgc to the river.

32 Ura:iium mill efiluent v..ash at Mexican Hat, Utah. Sample taken from the effluent !;ash i:I-.ich czicers tile San Juan River below the mill.

33 Moenkapi \!ash ai: hbc::kopi_, Arizona. . Sample t:iltcn at the bridge on Indian Route 3 just bcio~the 'Tuba City uranium mill. The

I t,ash \cas dry at the tim of the August 1363 survey.

33.5 Moenkopi C.'ash belot; Tuba City, Arizona at U. S. J9 Highway bridge. 35

Station Number

34 Colorado Rivcr at Lee's Ferry, Arizona. Smplc taken 5 miles north of U. S. J9 at the end of Lcw's Ferry roacl along the lest bank of che rive. .

35a. Las Vcgas Bay area OS Lake Mead. Sample collected near the mouth ol L~tsVcps [lash.

b. Templc Bar-Picxcc Ferry area oi Lalcc :.led. Samplc takcn 3t the wcsterii entrancci to Ctand Canyon.

C. Sample taken in Lns Vegas Eay opposiie Gypsum kash.

J. Sample talcen in Las Vegcis Bay opposite Govcrcment \!ash.

36a. Colorado RiLctr at heati of Lakc Iqcad. Sample takcrr at the trestcrn entrance t!, Grand Canyon.

b. Templc Bar-Pierce Fti-~yarea of La!x Elead. Sample takcii at the narrorling 0; the chanilcl above Pieice Fc-iry.

C. Lake Meaa. Sample takc,i st mid- lake opposite Pierce Ferry.

a. Lake Mead. Sample taken midvay betwell Pierce Ferry and Grand \aJash. Pepth at this point was about 25'.

C. Lake Mcad. Samplcb taken in the Lakc Mead main channel opposite Grail6 Wash. Lkpth uas aboul: 4U'.

37a. Lake Meati. Sample takt.ii mickay be ti.cscn Sani'y Point and Iccbclrg Reel-. Dctpth abou; 2i:O'.

b. Lake Mexi. Ssmplt taken midiJay between Sawy Point and Virgin Canyon tomrci the sauth short. ol tlic ialw. Depth about 200'.

33 Coloiado Rivcr tielow Hoovcr Dan. Sample tskcn at G!illot. Beach along the c.Jst baik ~~LI.CFn tile coiicessi3n ani the i ish hatchery.

39 L.11w Mohavc. Sample takcti at mid-lake above. Uavis Dam just above Bu1:shead Rc;(:k.

40 Laice Mohavc. Sample. ta!ccn abcut 3 milt-s absJvc Davis Dam opposite :ne cabiiis r,r, ilhe east shorc.

41 Coloraao RAvCr at ;Jcbcdlcs, Caiiforiiia. Sample taken from the Govcrnmcn t br iC:gc by drccigc. 36

Station -Number

CO Lake Havasu. Sample taken abbut 4 iirilcls above Parker Dam opposite Bluegill Ts land.

43 Lake Habasu. Sample tdlceti opposj te the> KctropcJlitan G!ater District of Southern Calilornia int-ilce, about 6VO' fro9 tire west shore.

44 La!ce Havasu. Sclspfe taken abcut 11'2 mile above Parker Dam under the potacr lines.

45 Coloraiio Kiver at Yarkcr, Arizona. Sample taken ahng the vest 5anlc under ch.lc ,lrizorra 72 High .iy bridge.

46 Colorado RLvcr abovc Imperial Cam. S;l;ilplc taken in the reservoir main clidimel dbovt miles abwe Imperial Dam.

47 Colorado Riw?. above Iiiipcrict? Dam. Sample takcn in the center of Squat, Lake off tlie rest.r\;oir rnLiiL: channt 1.

A: Colorado River above IinpcriAl Dam. Samplc taken in the main channel abou; i mile above tlic dam.

43 Calorado River ai Yti.na, Arizona. Sample taken fiom the U. S. 95 Highiiay brj-Lgc.

5 ih Sa:i Juan Riv?r at Sniplock, N?\J Mexico. Sample takcn from the U. S. 66' Higliray bzicp.

b San Ju3.i Rivcr at Shiprock, Nev Me:~ico, uranium mill e:fluent seepage channel.

50.5 Sar. Juan River 6 miles below Shiprock, Neu Mexico.

51 San Juan River beloi.. Fdrmii:gtGn,Net. Mexics. Sample takcm mar Kirt- land, Nev Eic:;ico, bcioi, coriiluc 11ce OL tile himas River , approximately 1 mile east of Kirtlanc!.

52 San Juan River above Farr:nir.gtcn,Ncv Plcxico. Sample talccn above the Animas River COA; luencc, apllro::matcly iC miles east ol' Farmingtoii just otf Nci Mexico 17.

53 Aiiimcls F.ii:er at F'a~lnii~gtoi~,Ncmv Picxico. Sample ,akcn at tlic bridge on NCW i.lC:ii

54 Animas River at Aztec, Nci: Me;.irl?.. Sawple taken 1/4 mile upstream from highixiy bric1,;c" on U. S. 5'.\1.

S,r Xiilmas River at C~?QraoO-Nel.;.Plcxico state Iiiit?. Sample takcn at the Riversice PHS Basic Data Statioil just oil U. S. 550. 37

Station Number

56 Animas River below Durclngo, Colorado. Sample taken 2 miles belov the Vanadium CcrporJtLon of America uranium mill.

57 ALiinias River above the Durango uiatiium cill. Sample taken at the Fish Hatchc1-y 011 U. S. 550.

53 Dolores River nbovc Slick Roc!<, Culoratio. Sample taken from iiighuy bricige 011 Colo,atio LO, ab3ut 2.5 miles abobt. the Slick Rock mill. x 5 9 Dolorcs River be:.ow Slick Rock, Culorado. Sample tdkcn about i/2 mile below the Slick Rock uranium 1x111. There tas no stream flow i at the time of the August 1.300 sur-ey. ! I I 60 Dolores River at Bedrock, Colcrdco. Sample tdlccri from the hizhvray bridge on the Indirt road through Bedrock.

61 Dolores River 350~~2conLLueucc oL San Miguel River. Sample taken 0.7 miles above tile mouth of the San MiGuel River.

62 San Miguel Rivcbr abouc. Natrurit~,Colorado. Sample taken trom the ;arm propercy adjacetit to the rivcr, approximately 1 1/2 miles abo%JeNaturitd.

63 San Miguel Riter Lclcw Vn,'corurn, Colbrado. Sample taken at the bricgc on a side road 1.2 milcs Lcloi: the mill.

64 Sail MigjJel Fiver above Ura\Tan, Coloratio. Sample taken at highway bridge on Colorado 141, 1.3 miles above the main intersection at Uravan.

65 San Nigur.1 River bclot Uravcln, Culorado. Sample taken about 1/2 mile above th;- mouth uf t!ie San 1vIiguel River.

66 Dolores River belov Sari i4i;;uel Rivcr. Sample taken from & bridge approximately 3 miles belor: thc ~r,ou:ii 0.2 thc San Miguel River.

67 Dolores River at Gatemy, Cclorado. Snmple taken immdiately beloti the Colorado 1k1 h:i$)\.ay bi. :dze.

63 Gunnisoii River at Dclta, Colorado. Sample taken irom Colorado 65 hightiay biidgcb 0 1ililt.s cast of Delta.

G': Gunnjson Rivcr belo[: Gunn-son, Coiarado. Sample taken along U. S. 50 about .; inj.les [:'?st of Gurinison.

70 Guaniso:i River bti1otJ the Gutinlscti uranium mill. Sample taken belotr the U. S. 50 iiigiitVay bridge 1 ni?c so1:.tht.cst OF Guiinison. 3'; i

S 1: ;I t ioii iqumbc;.

71

72

73 Tomichi Crcc!c bel01 irilc Gunnisoli mill. Sample taken about 1 1/2 inilcs bt.101: tlrc briLgc' on the inill ;-oat.

7 .!+

71

7G Roaring Fox!: River at G1c.m ooc' Springz, Colojrclc~u.

7;;

7s Tomichi Cree:: ;bo\/c Guiuiison, Color~~o.

.; i! Uncompahgrc Givci, Z miles south oi iiantrosc, Coloxado.

21 San Mi;;uel River abwe NJtui-I ira, Colorado.

'-I >& Little Sna!:e Rive: 17 ,,iil~s.,oi-thr cst OC llaybell, Coloiaao.

23 I!hite River at ;Iccltcr, Coloicltio. APPENDIX C

RADIOACTIVITY OF LAKE i4EAL) I:ATERS

In conjui-:Lfiorl T.-iC.i the comprehensive October 1C;GO sc.iiment survey in Lake Near r.ater saq1c.s \-.ere taken fox analysis of rai,ium aiIC uranium. Samples 02 suri'ace [;.ater, as 1. ell as kaccr at the 1iquiC:- sedimeirt iatcrfacc vere collcctec iki orier to observe iL leaching 02 radium anc uraiiium vas taking place Ixoin the bottom sediment. Table C-1 presents the data obtained.

& ;: ;:

From this table it is seen that lith the exccption of one anomalous .f result, all raciium concentrations are \.ell below the current MPC oi 3.0 vvc/l. Also no significant ciLEcrence vas observed betwen surr'ace and bot tom va ter.

:. ,

, 1, . 40 I ...

TABLE C-1 Radioactivity of Lake Mead Waters October 1960 Radioactivity Depth of Depth of Radium0226 Uranium Description Water, Ft. Sample, Ft. Station uuc/l. uc/l. LM-1 Emery Falls 5 0-1 -< 1.0 16 LM-2 Icet erg Canyon 120 5 1.1 7.3 0 120 -< 1.0 - LM- 3 Sandy Point 208 5 3.4 8.0 0 20 7 -< 1.0 10 LM-4 Virgin Canyon 30 7 5 1.3 6.3 307 -< 1.0 6.6 LM-5 East Point 2 75 0-1 -< 1.0 5.5 0 0 2 75 -< 1.0 Boulder Canyon 404 5 -< 1.0 - 403 1.2 .. LM- 7 Hoover Dam 420 5' -< 1.'; 8.1 ... 420 -< 1.0 8.0 .. LM-8 The Narrows 3 0-1 -< 1.0 0 LM-9 Overton 170 0- 1 0.4 0 - 170 0.5 0 LM-10 Virgin Narrows 2 75 5 0.4 5.8 - 2 75 0.4 0 LM-11 Henderson Intake - 5' -< 1.0 7.9 0 Bot tom 0.9 8.1