ENVIRONMENTAL PROTECTION TAGENCY
OFFICE OF ENFORCEMENT
RECONNAISSANCE
STUDY OF
RADIOCHEMICAL POLLUTION
FROM
PHOSPHATE ROCK MINING & MILLING
NATIONAL FIELD INVESTIGATIONS CENTER-DENVER
DENVER. COLORADO
DECEMBER 1973
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ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF ENFORCEMENT
Reconnaissance
Study of
RADIOCHEMICAL POLLUTION
FROM
PHOSPHATE ROCK MINING & MILLING
National Field Investigations Center-Denver
Denver, Colorado
o Revised
May 1974
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TABLE OF CONTENTS
Page
LIST OF TABLES ii
LIST OF FIGURES ii
GLOSSARY OF TERMS iii
SYMBOLS iii
DEFINITIONS iv
I. INTRODUCTION 1
II. PHOSPHATE ROCK MINING AND MILLING AND WASTE ,
SOURCE DESCRIPTION ... 5
MINING 6
MILLING 8
Wet Process Acid and Fertilizer Manufacturing. ... 8
Thermal Processes 11
Other Uses f . 11
III. RADIATION GUIDELINES AND STANDARDS 13
IV. STUDY RESULTS 18
BACKGROUND 18
FINDINGS 20
Mining 20
Milling 24
V. TREATMENT TECHNOLOGY 32
WATER 32
AIR 33
SOLIDS 36
VI. SUMMARY AND CONCLUSIONS 38
VII. RECOMMENDATIONS 42
VIII. REFERENCES 44
APPENDICIES
A. Analytical Methods and Quality Control A-l
B. Draft Report on Radium-226 and Radon-222
Concentrations in Central Florida Ground
Waters
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LIST OF TABLES
Table No. Page
1 MAJOR PHOSPHATE ROCK MILLS IN THE UNITED STATES ... 9
2 RESULTS OF RADIUM ANALYSIS - PHOSPHATE MINING
AND MILLING AREA SAMPLES. 21
LIST OF FIGURES
Follows
Figure No. Page
1 URANIUM-RADIUM FAMILY 2
2 MAJOR PHOSPHATE ROCK MINING AND MILLING- SITES .... 6
3 FLOWSHEET, FLORIDA AND NORTH CAROLINA
PHOSPHATE ROCK MINING AND BENEFICATION 6
4 FLOWSHEET, WET-PROCESS PHOSPHORIC ACID
MANUFACTURE 9
5 FLOWSHEET, "DOUBLE LIMING" TREATMENT OF
GYPSUM POND WATER 32
ii
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GLOSSARY OF TERMS
Ci - Curie, the basic unit intensity of radioactivity
in a sample of material. One Curie equals 37
billion disintegrations pep second, or approxi-
mately the radioactivity of one gram of radium.
g - weight in grams = 0.002205 pounds
k - kilo, used in conjunction with other synbols 39 a prefix
for thousand = 10-*
2
km - area in square kilometers = 100 hectares or 0.3861
square miles
1 - volume in liters ** 0.2642 gallons
m - milli, used in conjuntion with other symbols as a
prefix for one thousandth = 10
m - length in meters = 3.281 feet or 1.Q94 yards
man-rem - a unit of exposure dose of gamma radiation
MFC T- maximum permissible concentration used in limiting
radiochemical materials in air or water
metric ton - equals 1000 kilograms = 2205 pounds
p - pico, used in conjunction with other symbols as a prefix
for one millionth of one millionth = 10
V - micro, used in conjunction with other symbols as a prefix
for one millionth = 10~6
iii
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DEFINITIONS
beneficiation
contaminated
water
continuous
exposure
half-life
occupational
exposure
piezometric
map
slurrv
unrestricted
area
combination of chemical and physical processes
anplied to an ore to increase the concentration
of desired minerals
recycled process water used in wet-process phos-
phoric acid plants for pypsum slurry, transport,
barometric condenser feed, and flume scrubbers
- exposure to radiation for 168 hours per week
the time, required for a eiven amount of a
radioisotope to decay to one-half that amount
exposure to radiation durinp the normal working
period. considered to be 40 hours per week
a contour map of an imaginary surface to which the
water in an artesian aquifer would rise
a mixture of water and solids that can be punned
and that will flow
areas, including residential nuarters, for which
control is not maintained for the purpose of
protecting individuals from exposure to radiation
iv
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I. INTRODUCTION
The mining, beneficiation, and milling of phosphate rock is a
major segment of the U. S. mining industry, in terms of both tonnage
and sales. During 1972, approximately 38.5 million metric tons (42.4
million tons) of phosphate rock were mined in the U.S., an increase
of 40 percent from the 27.2 million metric tons (30 million tons)
mined during 1968. The U. S. produces approximately 45 percent of
the world output of phosphate fertilizers. This production contains
over 4.5 million metric tons (5 million tons) of phosphorous. Phosphate
rock and phosphate fertilizers are major export items of this country.
Much of this export is to Western Europe, Japan, and Israel and has a
value of approximately $100 million per year. A large portion is
exported in the form of phosphate rock which is subsequently milled
to produce phosphate fertilizers at the point of use.
The United States is one of the world's major consumers of phosphate
fertilizers, followed by Western Europe and the Communist nations in
terms of total phosphate usage.
"Phosphate rock" is a commercial term for a rock containing phos-
phate minerals, usually calcium fluorophosphate, in sufficient concen-
tration to permit its use in commercial products (Lewis, 1970), It may
be of either the sedimentary or igneous form, although the sedimentary
form is the more common.
Phosphate rock does not have a definite chemical composition. The
major phosphorous minerals of most phosphate rock are in the apatite
group and can be represented by the formula Ca,(PO ) (F,C1,OH). The
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(F,C1,OH) radical may be any combination of the fluoride, chloride, or
hydroxyl ions, while the (PO.) radical can be partly replaced by the
vanadate, silicate, sulfate, or carbonate ions. Rare earths, chromium,
and uranium are other common impurities. Uranium concentrations vary
directly with the phosphate concentration of phosphate rock and usually
are in the range of 40 to 165 grams of uranium per metric ton (0.1 to
0.4 pounds/ton) of rock (Bates, 1969). This uranium was deposited con-
temporaneously with the phosphate rock and is incorporated in the grain
structure. Uranium was recovered from phosphoric acid produced from
phosphate rock on a commercial basis at three plants during the 1950's
(Kennedy, 1967). Two plants are currently in the construction or plan-
ning stage for the recovery of uranium from phosphoric acid. The
presence of uranium in phosphate ore is used to advantage in gamma-ray
prospecting for new phosphate rock deposits.
Since natural uranium contains approximately 99.28 percent uranium-
238 and 0.71 percent uranium-235, the decay chain of uranium-238, known
as the uranium-radium family, is of primary importance. The isotopes
formed from uranium-238 are shown in Figure 1 along with their mode of
decay and half-life and present varying degrees of hazard. From the
standpoint of water pollution, the radioisotope radium-226 is the
most hazardous. It has a maximum permissable concen-tration (MFC)
an order of magnitude less than any of the. other decav isotopes.
Phosphate rock contains approximately 50 microcuries of radium per
metric ton (45 microcuries per ton).
Radium tends to replace calcium in bone. It was shown to be of
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u238
92
Alpha
4.5 x 10
( ,
Alpha
8.0 x 104 yr
( .
Beta
26.8 min
c .
Beta
S.O day
Th234 T- Pa234 - U234 Th230
90Th 91?a " 92U ' ~^90Th
Beta Beta Alpha
9 yr 24.1 day 1.1 min 2.5 x 105 yr
- 226 . 222 . 218 _ 214
onKa ' '" *" Q,Kll " ' ' * 0. I'D ' > ooP"
oo bo 84 82
Alpha Alpha Alpha
1620 yr 3.8 day 3.05 min
B.2U
Beta Alpha Beta
19.7 min 1.6 x 10"4sec 22 yr
84Po **82Pb
Alpha STABLE
140 days
)
-)
)
Figure 1. Uranium-Radium Family (FHPCA, 1966)
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prime importance in the control of radiochemical pollution from uranium
mills throughout the Southwest (FWPCA, 1966). As a result, a great
amount of effort was expended in stabilization of tailings piles from
the various uranium mills in the Colorado River Basin. Measures such
as chemical coatings, soil cover, and vegetative stabilization were
employed.
Radium-226 decays by alpha emission into radon-222, a radioactive
gas with a half life of 3.8 days. The decay products of radon-222, in
turn, are particulates which can be adsorbed onto respirable particles
of dust. Radon and its decay products has been implicated in an increased
incidence of lung cancer in those workers exposed to high levels (Bureau
»
of Mines, 1971). Heating or grinding of phosphate rock woxild liberate
radon and its decay products to the surrounding atmosphere.
It is generally agreed that unlike other materials, there is no
threshold value for radiation exposure. Accordingly, the Federal
Radiation Council has repeatedly stated that all radiochemical material
releases are to be kept to the minimum practicably obtainable. The
Council states "It should be general practice to reduce exposure to
radiation, and positive efforts should be carried out to fulfil the
sense of these recommendations. It is basic that exposure to radiation
should result from a real determination of its necessity (Federal
Radiation Council, I960)."
From the information available it was determined that a recon-
naissance study of the phosphate mining and milling industry was
necessary to investigate the magnitude of radiochemical pollution to
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receiving waters. This report describes the findings of the study
and other related problems associated with processing of phosphate
fertilizers, such as air pollution,.ground-water contamination,
possible deleterious consequences of fertilizer use, effects on
other receiving water uses, including shellfish and drinking water
supplies, and the use of by-product material in the construction
industry. Throughout the report a comparison has been made of reconnais-
sance sampling results with promulgated radiochemical standards and
guidelines.
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II. PHOSPHATE ROCK MINING AND MILLING
AND WASTE SOURCE DESCRIPTION
The comprehensive work on the occurrence and milling of phosphate
rock into phosphoric acid and phosphatic fertlizers is the book by
W. H. Waggaman (1952), titled "Phosphoric Acid, Phosphates and
Phosphatic Fertilizers". Additional information is contained in
U. S. Bureau of Mines Information Circulars 7814 (Ruhlman, 1958) and
7951, (Waggman and Ruhlman, 1960). All of these reports, and others
(McKelvey, 1967, and Menzel, 1968) contain mention of the widespread
occurrence of uranium in phosphate rock.
The U. S. Environmental Protection Agency (EPA) and the U. S.
Public Health Service (PHS) have commissioned a number of studies of
the pollutional aspects of phosphoric-acid manufacture. Two of these
(Manufacturing Chemists Association and Public Health Service, 1968 and
1970) deal with the air pollution problems associated with the industry.
Two EPA grants (Battelle Memorial Institute, 1971 and Datagraphics, Inc.,
1971) deal with the liquid waste components of the phosphate industry.
The radiation problem is not addressed in these documents.
Phosphate rock deposits are well distributed throughout the world
but those satisfying current world requirements, for the most part, are
located in the United States, North Africa, and Russia. Large, undevel-
oped deposits in Peru, Spanish Sahara, and Australia are expected to be
exploited in the future.
In the United States, 83 percent of the phosphate mining in 1968
was done in Florida and North Carolina, with the bulk of this done in
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Florida (Bates, 1969). Tennessee supplied 6 percent of the 1968
national production, and deposits in the inter-mountain West supplied
11 percent. The Tennessee deposits are near depletion and are expected
to become less important in future years while the North Carolina
deposit will assume greater importance. The locations of phosphate
mining and milling areas throughout the nation are shown in Figure 2.
Much of the phosphate mined in the Tennessee, North Carolina, and
Western mining areas is converted to fertilizer near the site of the
mining. A major portion of the Florida rock is transported by barge
throughout the U. S. and milled at areas near the site of use. Barge
transportation is required for economical movement of the raw rock.
MINING
The mining techniques [Figure 3] employed In the various mining
areas are different, and are dependent upon geologic and hydrologic
conditions which exist at the mine site. The impurities which are
present in the phosphate rock vary from place to place.
In the Florida land-pebble deposits, the overburden is removed and
the ore mined by large electric draglines. The ore Is slurried and
pumped to the washing plants which are often located several kilometers
from the mines. Those particles less than the 200-mesh size, called
slimes, are discharged from the washing plant. In the Florida field
located south of Lakeland, the slime slurry frequently comprises up
to 1/3 of the total mined tonnage (Lewis, 1970). The slimes are
similar in chemical composition to the original ore matrix, but are
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/<*lrZr=> -*^ >, _x* N nw- '
^5Cu ft*? X* A
V FLORID* HARD ROClh, .
>?S> ) .
A MINING AREAS |
WET - PROCESS j
FERTILISER PLANTS j
THERMAL PROCESS
PLANTS
Figure 2. Major Phosphate Rock Mining and Milling Sites
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COARSE ROCK
ORE
WELL FT
WATERf"
a:
UJ
t
«*
*
UJ
LURRY GIA
UJ
oc
I MINE
1
PIT
1 MATRIX 1
NTJ SLURRY 1
\
SCREEN
L
CO
1
1 1 AMINE 1 FINE ROCK! 1
| *| FLOTATION 1 *| GRIND | *
SLIME PONI
d
n
j
r
t
:
SAND TAILS
i
in
UJ
i
H REAGENT SURGEJ "
POND 1 o
ae
o.
ee
Ul
rsl
_j
t
UJ
C5
SEEPAGE
Figure 3. Flowsheet, Florida and North Carolina Phosphate Rock Mining and Benefication
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extremely difficult to trc.it or debater. The resultant slnrrv of clay-
size sline particles an'' wntor occupies a volume much larger than tho
original volume of the ore. Mined-out pits are frenuentlv used for
storage of a nortion of the slime slurrv, however additional storarc
volume, in the form of surface ponds is usual]v required. Frequent
breaks of the slime nond dikes have nlamed the. Flor-fdn mining industrv.
The material, larger than ?.0fi-mesh is treated in an amine flota-
tion circuit. In this procedure, the silica sand in the ore is sepa-
rated and either slurrled to sand niles, used in construction of the
perimeter of the slime ponds, or placed in nlned-out areas. The spent
amine flotation watfr is discharged to mined-out areas and rp.c.vcled.
The separated phosnhate rock is then either sold for exnort or sent to
a nhosphate mill for further processing
In "orth Carolina the mine located near Aurora has a number of
hish-capacity wells that are continuously pumped. This pumpape permits
drv mining by lowering the water table almost 60 meters f?00 feet), to
below the ore level. A 5S cubic meter (72 cubic vard) dragline is used
for strippinc overburden and pilin? the ore on the mine, surface. A
smaller dragline then moves the ore to the site of a hydraulic ore
washer. Water from the dewaterin^ wells is used for ore slurrv and
slime transoort, and then discharged into the Pamlico River. Anv see-
page from the ponds moves toward the mine when it is pumped from the
dewaterinp wells. The amine flotation circuit is a closed svstem, with
no surface discharge.
The North Carolina operation involves movement of a greater amount
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of overburden than at the Florida mines. North Carolina ore is similarly
screened and floated in an amine flotation circuit. The North Carolina
slimes dewater much more easily than do Florida slimes which eliminates
the need for extensive slime storape. The solids are retained on a
sinnle slime storage pile.
The Tennessee and intermountain mining districts hoth generally
involve dry mininp techniques, utilizing shovels for ore removal and
trucks for ore transport. Much of the western ore is of sufficient
prade to permit direct use without beneficiation (Rates, 1969). Mininp
in these districts does not have a p,reat potential for water pollution.
MILLING
Following minine and amine flotation, the phosphate rock must be
converted into a relatively soluble product bv use of either of two
methods. The first is acid treatment which consists of reacting the
phosphate rock with various acids. The second consists of either
thermal reduction of the phosphate rock or other thermal treatment.
The major phosphate mills in the U. S. are Riven in Tahle 1.
Wet Process Acid and^ Fertilizer Manufacture - Tn wet process
plants fFipure 41, phosphate rock is reacted with acid, generally
sulfuric, to produce phosphoric acid and a waste product hvdrated
calcium sulfate (gypsum) (Lewis, 1970). The acidulation reaction is
<»iven by Equation (1).
Ca10F9(p(V6 + lOHjSO^ -I- 20H20 -^lOCaSCy 2l!?n + 2HF + 6H PO^ (1)
-------
imusT
| FLASH | |
| COOLER 1 ~*
1
PHOSPHATE 1
ROCK U, Ri.
«0 |Ci/|| *' | f
U.
FUME SCRUiml
1
1
1
1
IACIO +u". RI
""' 110 »Ci/l|
Ri
(20 lCi/1)
M
O
* «
^suT
1 TA
SUIFURICI MIXER 1
ec
teJ
1
C
*
LEGEND
Nl! 1
Bril
"l
1
'* ^1 6YPSUM PILE j »«
^1
SEEPACE Ri "1
(FERTILIZER
PLANT
II
ISO pCI/l)
190 pCi/l| 6Y?SUM '1 'Y '"'"'
^" WATER PONO|
»- 6AS STSEAM
(25 iCI/lj TYPICAL RADIUM CONCENTRATION
SEEPACE Ri
(90 >Ci/l|
[ IAITERNATIVE TO TREATMENT!
1
1 DOUBLE LIME
TREAT
1
STREAM
Figure 4. Flowsheet, Wet-Process Phosphoric Acid Manufacture " pCi/"
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TABLE 1
TIA.TOR PHOSPHATE ROCK MILLS
IN THE UNITED STATES
Company
Location
WET PROCESS PHOSPHORIC ACID PLANTS
W. R. Grace
Allied Chemical Corp.
ARKLA
Borden, Inc.
C. F. Industries, Inc.
Mobil Oil Corp.
Olin Corp.
Royster Co.
Stauffer Chemical Co.
Texasgulf
Gardinier, Inc.
Freeport Chemical Co.
Atlantic Richfield Co.
Becker Industries Corp.
National Phosphates
(Hooker Chemical, Becker)
Agricultural Products Corp.
(El Paso Products Co.)
Borden, Inc.
Farmland Industries, Inc.
Mississippi Chemicals Corp.
N. Idaho Phosphate Co.
(Bunker Hill Co.)
Occidental Chemical Co.
Occidental Chemical Co.
Olin Corp.
Penzoil United, Inc.
J. R. Simplot
Union Oil of California
U. S. Steel Corp.
Valley Nitrogen Producers
Agrico Chemical Co.
U. S. Steel Corp.
Central Phosphates, Inc.
Bar tow, Fla.
Geismar, La.
Helena, Ark.
Piney Point, Fla.
Bartnw, Fla.
Hepre, T.I.].
Pasadena, Tex.
Mulherrv, Fla.
Pasadena, Tex.
Aurora, N.C.
East Tampa, Fla.
Uncle Sam, La.
Ft. Madison, Iowa
Marseilles, 111.
Taff, La.
Conda, Idaho
Streator, 111.
Green Bay, Fla.
Pascactoula, Miss.
Kello»»p, Idaho
Lathrop, Calif.
White Springs, Fla.
Joliet, 111.
Hunford, Calif.
Pocatello, Idaho
Nichols, Calif.
Ft. Meade, Fla.
Helm, Calif.
So. Pierce, Fla.
Wilmington, N.C.
Plant City, Fla.
THERMAL PROCESS PHOSPHORUS PLANTS
Holmes Co.
FMC
Mobil Chemical
Monsanto Co.
Monsanto Co.
Hooker Chemical
Stauffer Chemical
Stauffer Chemical
Stauffer Chemical
TVA
Pierce, Fla.
Pocatello, Idaho
Nichols, Fla.
Soda Springs, Idaho
Columbia, Tenn.
Columbia, Tenn.
Silver Bow, Mont.
Tarpon Springs, Fla.
Mt. Pleasant, Tenn.
Muscle Shoals, Ala.
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10
During the initial acidulation step, ground phosohate rock is mixed
with acid in a reactor attack vessel to form phosphoric acid or super-
phosphate and calcium sulfate. When ordinary superphosphate is the
desired product, enough sulfuric acid is used to convert the phosphate
into water soluble superphosphate [Ca(H.PO.)-H?0]. Calcium sulfate
is not separated from the product. To produce phosphoric acid, addi-
tional sulfuric acid is added, and the resultant phosphoric acid is
separated from the gypsum in a pan filter. Fumes from the exothermic
reaction are collected and treated with water scrubbers, with the scrub-
bers generally fed by contaminated (recycled) gypsum-pond water. A
portion of the phosphoric acid can be reacted with additional phosphate
rock to produce triple superphosphate or combined with potash or ammonia
to produce complex fertilizers.
Available data (Habashi, 1970: Kennedy, 1967; Spaldinp, 197?.) indi-
cates that there is a partitioning of uranium and its decav products
during the acidulation step. Virtually all the uranium remains with
the fertilizer, while a major portion of the radium and subsequent decay
products are removed in the liquid and solids wastes. Technology exists
and has been utilized to recover uranium from the raw aci<1 through
solvent extraction. This would not, however, have any effect on the
radium or radon decay products.
Calcium sulfate in the pan filters is rinsed with weak acid and
contaminated water, discharged to a slurry tank, and slurried for trans-
port from the plant. General industry practice consists of discharging
the slurry that contains the radium waste to a gypsum pile, decanting the
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11.
clarified water from the pile, and recirculating it to the slurry tank.
However, three plants (National Phosphate, Freeport Chemical, and
Allied Chemical) located on the Mississippi River in Louisiana upstream
of New Orleans, are reported to discharge the gypsum slurrv directly to
the Mississippi River, with no removal of the solids. Because of the
soluble nature of gypsum, the calcium sulfate and anv radium will
subsequently be dissolved into the Mississippi River waters. Mo direct
discharges of gypsum are know to exist at other plant locations in the
country. Two other plants (ARKLA at Helena, Ark. and Becker Industries
at Marseilles, 111.) are reported, however, to discharge a slurry decant.
Thermal processes - Thermal processes for producing phosphate con-
sist of both thermal reduction, in which phosphate rock is smelted with
a mixture of carbon and siliceous flux in electric furnaces, and processes
without reduction that heat phosphate rock with an alkali salt or silica
to produce useable products. For the most part, thermal processes for
phosphate production do not involve liquid effluents, other than liquid
used in scrubbing gaseous streams.
Radon and its decay products are liberated during the thermal pro-
cessing of phosphate rock. This radon gas may pose occupational hazards
in the immediate processing area. In addition, it is estimated that up
to 10 percent of the incoming radon and decay products are discharged in
the stack effluent to the ambient atmosphere (Atomic Energy Commission,
1970 and Lammering, 1972).
Other Uses - There are many other uses for phosphate rock which do
not use either the wet-process or thermal process. The larcest of these
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12
is the production of def.luorinated nhosphate rock (DPR) for animal feed
supplements. In this procedure, phosphate rock is calcined to liberate
fluorine which is present in all phosphate rock. A study by Uabashi
(1967) indicates that a beef animal fed a daily ration of one half
kilogram DPR would receive approximately 20 times the permissible
intake of uranium. No data were given on the radium burden, but it
would be relatively higher than the uranium burden.
By-product gypsum that contains radium is presently being used as
an inferior grade of wallboard in parts of Europe and Japan. This rep-
resents a potential environmental hazard which will be discussed later.
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13
III. RADIATION GUIDELINES AND STANDARDS
Numerous guidelines, recommendations and standards for protection
apainst radiation have been published by the Atomic Energy Commission
(AEG) and various committees such as the National Committee on Radiation
Protection (NCRP), International Commission on Radiological Protection
(ICRP), and Federal Radiation Council (FRC). The following summary
provides an indication of the quantities of Ra-226 allowable in the
water environment as established by a variety of sources:
(1) The PHS Drinking Water Standards (1962) provide standards
applicable to potable water used by carriers subject to the
Federal Quarantine Regulations. However, these have frequently
been used as a ready reference for guidance on water quality
limits where other standards do not exist. The limit for Ra-226
in drinking water is 3 picocuries per liter (pCi/1). However,
at or about this level, a water supply may still be approved
if surveillance of total intakes of radioactivity from all
sources are within limits recommended by the FRC for control
action. At this concentration a daily water intake of 2 liters
per day would result in an intake of 6 pCi/dav in the absence
of other sources. The FRC control action includes quantitative
surveillance and routine control within the range of 2-20 pCi/day
for Ra-226 (Public Health Service, 1962).
(2) The National Bureau of Standards (1959) Handbook 69 provides
a series of recommended levels of about 200 radioisotopes for
occupation exposure. The handbook indicates a maximum permissible
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14
concentration (MFC) of Ra-226 in water of 10~ pc/cc (100 pCi/1)
for continuous exposure to the critical organ, in this case
bone. For persons outside the controlled area, this is reduced,
to levels not exceeding one-tenth the MFC's for continuous
occupational exposure, or 10 pCi/1. This level may be an
average of a period of up to one year.
(3) The International Commission of Radiological Protection (ICRP)
(1959) recommends the same MFC values as given above in Handbook
69. However, the ICRP recognizes three population groups whereas
NCRP recognizes only two. The additional group is the "population
at large." The report specifies that concentrations "in air or
water, applicable to the population at large, should not exceed
one-thirtieth of the MFC values for continuous occupational
exposure ..." Thus, the recommended MPC value for Ra-226 in
water for the general population is 3.3 pCi/1.
(4) In 10 CFR 20 (1960) radioisotope levels are presented which
apply to AEC licensees. Table II in Appendix "B" of these
standards list effluent limits to an unrestricted area for
soluble Ra-226 in water of 3 x 10 yCi/ml (30 pCi/1), above
natural background. This level may be averaged over a period
not greater than one year. The level may be reduced by the AEC
for specific periods of time if the average daily intake from
all sources would exceed the daily intake from air and water
at one-third the concentrations in Table II of Appendix "B".
Under these circumstances, effluent concentrations could be
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15
reduced to an unspecified level. This in effect would allow
the AEC to average concentrations so as not to exceed their
specified levels. Other portions of 10 CFR 20 provide that
not over 0.1 yCi/day of radium may be discharged into a
sanitary sewer system and that not over 0.01 mCi/day of radium
may be buried in any one location.
(5) Under Section 304(a)(l) of the Federal Water Pollution Control
Act of 1972, EPA is required to publish water quality criteria.
In October of 1973, EPA proposed "Criteria for Water Ouality"
which stated inpart that "When raw water is consumed directly,
the maximum acceptable concentration of naturally occurring
radionuclides having alpha ray emitting daughters, e.g.,
radium-226, -228, etc. is 5 pCi/1; and the maximum acceptable
aggregate dose to the population served by the water supply
is 3,000 man-rem/year, unless the radium-226 activity is less
than 0.5 pCi/1" (EPA, 1973).
AEC promulgated regulations (10 CFR 20, 1960) differ from ICRP,
NCRP, and FRC recommendations by being regulatory statutes set forth as
federal law rather than just recommended guidelines for radiation
exposure protection. The regulations establish standards for protec-
tion against radiation hazards arising out of activities under licenses
issued by the AEC pursuant to the Atomic Energy Act of 1954 and apply
to "all persons who receive, possess, use or transfer by-product material,
source material, or special nuclear material under general or specific
licenses issued by the AEC". A general license is effective without
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16
the filing of applications with the Commission or the issuance of
licensing documents to particular persons. Specific licenses are
issued to named persons upon applications filed pursuant to the regu-
lations. The use of radioactive material or other sources of radiation
not licensed by the Commission is not subject to the regulations. As
far as is known, none of the phosphate fertilizer plants are holders of
specific AEC licenses although they may be covered by the general
license criteria because of presence of "source material." The AEC
regulation 10 CFR 40 (1961) defines "source material" as (1) uranium
or thorium, or any combination thereof, in any physical or chemical
form, or (2) ores that contain by weight one-twentieth of one percent
(0.05 percent) or more of (i) uranium, (ii) thorium, or (iii) any
combination thereof.
The regulations (10 CFR 20, 1960) further state that in addition
to complying with the requirements set forth, licensees should "make
every reasonable effort to maintain radiation exposures, and the release
of radioactive materials and effluents to unrestricted areas, as far
below the limit specified as is practicable." The "limits" are not
maximum doses or exposures that can be applied safely with no hazard
but are guides for "maximum" exposure. The underlying philosophy of
radiation protection is that exposures should be maintained at the
lowest practicable limit.
In the case of air quality, both the Bureau of Mines and the
Occupational Safety and Health Administration have standards relative
to radiation. Both arise, however, in recognition of the occupational
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17
hazard resulting from radon in uranium mining operations. The Bureau
of Mines regulations (30 CPU 57) prohibit exposure to airborne con-
taminants exceeding the threshold limit values in the publication
"Threshold Limit Values of Airborne Contaminants". This document,
however, incorporates NBS Handbook 69 for permissible concentrations
of radioisotopes in air. Exposure to radon daughters is further
limited in terms of "working level months" (WLM). A "working level"
(WL) is any combination of the short-lived radon daughters which will
result in the ultimate emission of 1.3 x 10 million electron volts of
potential alpha energy in one liter of air. One WLM results from
exposure to one WL for 170 hours. The regulations prohibit an exposure
of 6 WLM in any consecutive 3-month period and 12 WLM in any consecutive
12-month period. In addition, with atmospheric concentrations between
1.1 and 2.0 WL, immediate corrective action must be taken, and when
above 2.0 workers must be withdrawn until such action is taken.
The Occupational Safety and Health Administration limit occupa-
tional exposure in mines to no more than 2 WLM in any calendar quarter
and no more than 4 WLM in any calendar year. Applicability of either
set of standards to other than mining operations would be questionable.
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18
IV. STUDY RESULTS
BACKGROUND
It is widely known that most phosphate ores contain uranium as an
impurity. Uranium and its decay products are likely to be present in
the products, or in wastes from the processing of such ores.
A report (Spalding, 1972) obtained from Texas A & M University
indicates that significant increases in the uranium concentration of
cropland runoff has resulted from fertilizer application. The report
concluded that the uranium concentration in the Gulf of Mexico has
increased as a result of fertilizer manufacture and application.
During the course of preparation for an industrial waste survey
of the Olin Corp. phosphate fertilizer plant at Pasadena, Texas,
personnel from National Field Investigations Center-Denver (NFIC-D)
noted that the Olin permit application reported alpha activities of up
to 600 pCi/1 in the Olin effluents. During the survey (August, 1972)
radium-226 concentrations up to 12 pCi/1 were measured in the effluents,
with up to 56 pCi/1 in the recirculated gypsum pond water. Olin
personnel indicated the pond water was only discharged during the
onset of a heavy rain.
Copies of the NPDES permit applications for virtually all phos-
phoric acid plants were obtained and studied by NFIC-D personnel. Most
plants, including those which formerly recovered uranium, indicated
in the NPDES application that radioactivity was not present in the
plant effluent. However, one plant (Allied Chemical) in Louisiana
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19
indicated a gross alpha concentration of over 6,000 pCi/1, while
another of the Mississippi River plants (Freeport Chemical) reported
almost 700 pCi/1 gross alpha. Both these plants also reported
extremely high suspended solids concentrations in the effluent, indi-
cative of the absence of gypsum ponds. It is calculated that each of
these plants discharge more radium than did any uranium mill in the
Southwest prior to initiation of control measures.
In the fall of 1973, NFIC-D conducted reconnaissance level sampling
of solids and liquids in the vicinity of phosphoric acid plants in
Idaho, Florida, and North Carolina. The NFIC-D effort was a screenlne
study to assess the relative magnitude of radiochemlcal problems from
the different components of the phosphate industry, in various geo-
graphic areas. Undoubtably, further evaluation will be required to
define the total radiochemical pollution problem from each phosphate
plant. Water sampling was conducted around two mines thought to be
representative of mining activity in Florida and one in North Carolina
that is the largest phosphate mining operation in the world. Phosphoric
acid plants sampled include one in North Carolina, four in Florida, one
in Texas, and two in Idaho. These plants have a combined total of over
25 percent of the U. S. production of phosphoric acid, and include
virtually all variations in wet-processes, with the exception of direct
discharge of untreated gypsum slurry to receiving waters.
Region VI personnel conducted sampling in phosphoric acid plants
on the Mississippi River which discharge gypsum slurries to the river.
These data are not vet available to NFIC-D.
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20
Limited air sampling was conducted by NFIC-Denver at two Florida
wet process plants. Other air sampling data have been collected by
AEC and EPA in the vicinity of thermal processing plants. EPA
presently has underway a comprehensive sampling effort at Idaho mills.
No sampling x^as conducted by NFIC-D within thermal processing
plants. The proposed effluent guidelines now under consideration
by EPA for these plants calls for zero discharge of process water.
FINDINGS
Results of radium analyses of samples collected during the NFIC-D
reconnaissance investigation are given in Table 2. Except where noted
these analyses were performed at the KFIC-D laboratory. Duality control
(Appendix A) was accomplished through the cooperation of TTERC-Las Vegas
and EPA's Eastern Environmental Radiation Laboratory.
Mining
As previously stated, during 1972 approximately 38.5 million
metric tons of phosphate rock were mined in the United States. Based
upon observed levels of radium in the ore, this would result in almost
2,000 curies of radium being exposed to the environment.
The mininp areas in both Florida and North Carolina practice
extensive reuse of water for transport and screening. Results of
radium-226 analysis of samples of these waters are given in Table 2.
It is emphasized that there are few planned releases of Florida mine
waters to surface streams. However, the water does seep into under-
lying ground water. In general, the mine water was found to be rather
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21
TABLE 2
RESULTS OF RADIUM ANALYSIS
PHOSPHATE MINING AND MILLING AREA SAMPLES
Radium
Pate Location Concentration
Liquid Samples, Mining Areas pCi/1
8/13/73 Agrico Payne Creek Mine recirculated water, Fla. 1.5
8/13/73 Agrico Palmetto Mine recirculated water, Fla. 1.1
8/13/73 Agrico Payne Creek Mine pit seepage, Fla. 0.61
8/13/73 Agrico Palmetto Mine pit seepage, Fla. 0.28
8/14/73 Unnamed mined-out pit near Bartow, Fla. 0.4
10/16/73 Texasgulf slime pond decant, N.C. 1,2
10/17/73 Texasgulf Lee Creek Mine dewaterlng wells, N.C. 0.09
Solids Samples, Phosphate Ore
8/13/73 Agrico Payne Creek Mine slimes, Fla.
8/13/73 Agrico Palmetto Mine concentration, Fla.
8/14/73 Royster ore, Mulberry, Fla.
8/14/73 C F Industries ore, Mulberry, Fla.
8/15/73 Gardinier Industries ore, East Tampa, Fla.
2/13/73 WHW8 ore (Unidentified EPA Reg. VI sample)
8/22/72 Olin Corp. ore (Florida rock) Pasadena, Texas
3/08/73 Simplot ore, Pocatello, Idaho
3/08/73 FMC ore, Pocatello, Idaho
10/17/73 Texasgulf Lee Creek, N.C. raw ore
10/17/73 Texasgulf Lee Creek, N.C. calcined ore
44
38
48
56"
47
60
48 (2)
33
30
17
18
Solid Samples, By-Product Gypsum
8/30/72 Olin Corp. new gypsum pile, Pasadena, Texas
8/30/72 Olin Corp. old gypsum pile, Pasadena, Texas
3/08/73 Simplot, Pocatello, Idaho
8/13/73 Agrico, So. Pierce, Fla.
8/14/73 Royster, Mulberry, Fla.
8/14/73 Amer. Cyanaraid abandoned pile, Brewster, Fla.
8/14/73 C F Industries, Mulberry, Fla.
8/15/73 Gardinier Industries, East Tampa, Fla.
10/18/73 Texasgulf Lee Creek, N.C. gypsum pile
1C-/18/73 Texasgulf Lee Creek, N.C. gypsum filter
(2)
(25
17
11
16
25,24
23,27
28,31
21,23
21,28
13
14
Liquid Samples, Streams and Wells
8/12/73 Peace River at Bowling Green, Fla.
8/15/73 Alafia River south of Plant City, Fla.
8/14/73 Well at trailer house near USS Ft. Meade, Fla.
8/29/72 Houston Ship Channel, Olin Corp. intake
10/18/73 Pamlico River east of Indian Island, N.C.
10/18/73 Pamlico River off Pamlico Beach, N.C.
10/18/73 Pamlico River off Gum Point, N.C.
10/18/73 Pamlico River off Core Point, N.C.
10/18/73 Pamlico River off Texasgulf barge slip
10/19/73 Albemarle River at Rt. 32 Bridge
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TABLE 2 (Cent.)
RESULTS OF RADIUM ANALYSIS
PHOSPHATE MINING AND MILLING AREA SAMPLES
Pate Location
Liquid Samples, Fertilizer Plants
8/13/73 Agrico So. Pierce, Fla. chemical plant gypsum water
8/14/73 . Royster gypsum water, Mulberry, Fla.
8/14/73 Royster seepage from gypsum pile, Mulberry, Fla.
8/14/73 Royster raw phosphoric acid, Mulberry, Fla.
Olin Corp., Pasadena, Texas
8/29/72 Gypsum water
8/22/72 Outfall E + F (2 samples)
8/22-29/72 Outfall A (Range of 4 samples)
8/22/72 Outfall C
Unknown mill, Sampled by EPA, Region VI
2/13/73 Sample WHW9
2/13/73 Sample WHW10
2/13/73 Sample WHW11
8/14/73 C F Industries gypsum water, Fla.
8/14/73 C F Industries experimental treatment of gypsura water.
8/14/73 Seepage off abandoned Cyanamid gypsum pile
Gardinier Industries, East Tampa, Fla.
8/15/73 Gypsum water before liming
8/15/73 Gypsum water after liming
8/15/73 Barometric condensers No. 1 and 2
8/15/73 Barometric condensers No. 3
.3/08/73 Simplot outfall 001, Pocatello, Idaho
3/08/73 Simplot outfall 002, Pocatello, Idaho
3/08/73 FMC, Pocatello, Idaho
10/16-18/73 Texasgulf Lee Creek, N.C. main outfall
10/17/73 Texasgulf Lee Creek, N.C. gypsum water
Radium
Concentration
pCi/1
92
97
8.8
21
56 (1)
0.4 to 12 (1)
0.3 to 2.0 (1)
0.2 (1)
32.7 (1)
0.5 (1)
31.8 (1)
91
0.04
12
65
7.6
18
0.45
0.14
0.58
0.06
"0.19 to 0.26
49
(1) Analysis by EPA,Water Planning and Standards, Cincinnati, Ohio.
(2) Analysis by EPA, NERC-Las Vegas.
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23
low in dissolved radium-226, generally between 1 and 2 pCi/1. Slimes
from a Florida mine were found to contain 44- pCi/g, or approximately
the same concentration of radium-226 in the solid material as in the
concentrated ore (48 pCi/g). These results indicate that failure of
a slime pond, with subsequent release of slimes to receiving waters,
may constitute, in addition to other deleterious effects, a major
source of radiochemical pollution to surface waters.
A water sample (Table 2) from the Peace River at Bowling Green,
Florida was found to contain 6.2 pCi/1 of radium-226; this is over
twice the PHS Drinking Water Standard. The Peace River was flooding
at the time of sample collection. A portion of the dissolved radium
in the river may be the result of leaching many tons of slimes that
have been deposited in the river due to slime pond failure. Over
the years, many thousands of tons of slimes have entered the Peace
and Alafia Rivers and their estuaries through slime-pond failures.
The North Carolina mining operation decants clarified water off
from the slime pond for discharge to the Pamlico River. Samples of
this detant contained approximately 1 pci/1 (Table 2), which is
greater than background levels, but one-third that of current drinking-
water standards. On the basis of the Texasgulf flow, this is equiva-
lent to 40 uci/day of radium-226 discharged to the Pamlico River.
Radium concentrations in the Pamlico River (Table 2) near the Texas-
gulf Lee Creek mine and mill were found to be approximately two and
one-half times the radium-226 level in the Albemarle River, a
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24
similar stream north of the mill. Published data (Spalding, 1972)
indicate uranium concentrations in Pamlico Sound that were higher than
normal background levels. Portions of Pamilco Sound are an approved
shellfish harvest area. A single sample of crab meat taken from
Pamlico Sound had less than detectable concentrations of radium.
No sampling was conducted in the Tennessee mining area. The
Western fields in Idaho and Montana are mined by dry methods and hence
use little water in mining processes. The area is rather low in rain-
fall, with the result that there is little surface water flow. Under
these circumstances, it is not expected that runoff from the mine areas
other than the slime pond would constitute a majorproblem of radio-
chemical pollution.
Milling
Published information and results of NFIC-D sampling indicate that
the largest component of radiochemical discharges to the water environ-
ment associated with the phosphate industry is from the wet-process
acidulation step. The sampling to date has shown that this acidulation
is responsible for major radiochemical water pollution and the generation
of massive amounts of solid wastes that contain radioactive material in
a readily leachable form.
Gypsum slurry transport water in mills using Florida phosphate rock
is extremely acidic, with a pH less than 2 and was found to contain
radium concentrations of over 50 pCi/1 for once-through gypsum trans-
port water, and 90 to 100 pCi/1 for plants practicing recycling [Figure 4
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25
and Table 2]. Examples include:
pCi/1
Agrico, So. Pierce (recycle) 92
Royster, Mulberry (recycle) 97
C F Industries, Bartow (recycle) 91
Gardinier, East Tampa (once-thru) 65
The AEC standard (10 CFR 20, 1960) for radium concentrations in
unrestricted areas is 30 pCi/1. Gypsum slurry transport water is
not normally discharged during dry weather conditions. However, as
noted previously, numerous occasions of slurry water discharge occur
during wet weather periods. Certain mills throughout the country that
use Florida phosphate rock presently discharge slurry water continuously.
In most of the Florida mills, decant from the gvpsum piles is
conveyed to a pond, generally constructed in a mined-out area, for
recycle to the mill. The bottom of such ponds consists of an artesian
limestone aquifer which, in turn, overlies the Floridian aquifer.
Reaction between the acidic gypsum transport water and the limestone
aquifer, together with solution cavities in the aquifer, has resulted
in the movement of highly radioactive water into the shallow ground
water of a large portion of Polk Country, Florida. The first indication
of this was obtained in 1966 during sampling by the Public Health
Service, Cincinnati, Ohio. A draft report (Appendix ?>) indicated that
values of up to 79 pCi/1 occur in the shallow ground water in the
vicinity of the °gypsum ponds. Sampling during the course of the NFIC-D
reconnaissance investigation, together with the PHS renort, indicate
that radium concentrations in the shallow wells throughout much of folk
County are greatly in excess of the PHS Drinking Water Standards (1962).
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Polk County is the high pressure point on the piezometric map of the
Floridian aauifer for peninsular Florida. Thus, radioactive ground
water will move radially in all directions in the Floridian aquifer
from the Polk County mining and milling site. No towns are known to
use x^ater exceeding the Drinking Water Standard for radium, although
several supplies, including those of Arcadia and Lake Alfred, approach
the value. Hox^ever, numerous individual and industrial supply wells
(Table IV, Appendix B) have been found to contain radium values three
to twenty-five times the Drinking Water Standard (PHS, 1962). Insuf-
ficient data exist to define the exact area of contamination. It
appears that the safety of water in the shallow artesian aquifer in
the areas of Range 23 East through Range 25 East, Townships 29 South
through 32 South, Polk County should be further evaluated with respect
to radium concentration. This is an area of over 1,000 square kilometers
(400 square miles). The domestic supply of an estimated 10,000 persons
is obtained from shallow aquifers in this area.
At the time of sampling (August 1973), the Gardinier (Cities
Service) plant at East Tampa v/as discharging single-limed gypsum pond
water and tailwater from the barometric condensers. The plant is
working to recycle both the pond water and the tailwater from the first
two condensers. The tailwaters from Condensers No. 1 and 2 contain
o
radium concentrations of 18 pCi/1 and should not be discharged. Tail-
water from the third-stage condenser contained 0.45 pCi/1 radium and
will continue to be discharged to Hillsborough Bay. The data (Table 2)
indicate that single-stage liming practiced by the plant reduces the
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27
radium concentration in the gypsum pond water from 65 to 7.6 pCi/1,
which is still greater than desired levels.
At the Texasgulf Lee Creek mill in North Carolina, samples of the
gypsum pond slurry water had radium concentrations of 49 pCi/1 (Table 2).
The slurry transport water is completely recycled and there is no
surface discharge to any receiving water. Other effluents composed
primarily of barometric condenser discharge and mine dewatering pumpage
contain radium concentrations of 0.19 to 0.26 pCi/1. These concentations
are well below any published guidelines or standards. Therefore, it
appears that radiochemical pollution in the receiving waters of Pamlico
Sound result almost exclusively from slime pond decanting rather than
any effluents from the milling process.
As previously noted, the Allied Chemical, Freeport Chemical and
National Phosphate plants in Louisiana discharge gypsum slurries con-
taining the by-product material directly to the Mississippi River with-
out impoundment. Liquid samples taken from one of these mills, pre-
sently unidentified, indicated dissolved radium concentrations of
32.7 picocuries per liter and 31.8 picocuries per liter (Table 2).
In addition, both samples contained extremely high concentrations
of radium-bearing suspended solids. Since specific data were not
available at the time of publication of this report, the exact loca-
tion of the sampling ooint is not known. It should be noted that
the discharges from the three Louisiana plants are upstream of the New
Orleans water-supply intake. Present EPA STORET files do not contain
information on radium concentrations in the New Orleans water supply.
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Sampling at the Olin Corp. plant outfalls at Pasadena, Texas, on
the Houston Ship Channel, showed radium concentrations generally within
the limits specified in various guidelines. However, one individual
sample was as hish as 12 pCi/1 (Table 2). Gypsum pond water, which is
discharged only during heavy rain storms, contained a radium concentra-
tion of 56 pCi/1. This value is nearly twice the allowable concentration
of 30 pCi/1 permitted by the AEC for release to an unrestricted area
(10 CFR 20, 1960).
Wastes discharged to the Houston Ship Channel eventually reach
Galveston Bay, parts of which are approved for commercial harvesting
of shellfish. Two samples of shellfish meat collected in Galveston
Bay, in February 1973, showed radium concentrations of 18 and 35 pCi/kg.
These levels are not considered to be significant concentrations for
dietary intake.
As previously noted, the wet-process for phosphoric acid production
generates a vast quantity, almost 25 million metric tons per year, of
impure gypsum. This is approximately the amount of concentrate acidu-
lated, and five times the phosphorus pentoxide O5/,1"* ) produced. Major
interest has been expressed in the use of by-product gypsum for con-
struction material manufacture. Due to the wide-spread occurrence
of pure deposits of gypsum and the relatively low-cost of storage space
available at U. S. plants, no use of the gypsum has been made in the
United States. However, such storage is not available at most of
the European or Japanese plants, and the by-product gypsum has been
incorporated in an inferior grade of gypsum wallboard. Currently, the
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U. S. Bureau of Mines is conducting a major investigation into the use
of by-product gypsum.
Samples of by-product gypsum were obtained fron plants in Texas,
Florida, Idaho, and North Carolina. Virtually all the gypsum samples
examined (Table 2) were found to contain between 15 and 30 pCi/R of
radium as listed below:
pCi/g
Olin Corp. new gypsum pile, Pasadena, Texas 17
Olin Corp. old gypsum pile, Pasadena, Texas 11
Simplot, Pocatello, Idaho 16
Agrico, So. Pierce, Fla. 25,24
Royster, Mulberry, Fla. 23,27
American Cyanamid» abandoned gypsum pile,
Brewster, Fla. 28,31
C F Industries, Mulberry, Fla. 21,23
Gardinier Industries, F,ast Tampa, Fla. 21,78
Texasgulf Lee Creek, N.C. gypsum pile 13
Texasgulf Lee Creek, N.C. gypsum filter 14
This is consistent with published data (O'Riordan, et al, 1972) which
indicate radium concentrations of 25 pCi/g in gypsum produced at English
mills. This study concludes that inhabitants of a house constructed
using wallboard made from by-product gypsum would receive one-tenth the
radon daughter exposure level considered safe for uranium miners, assuming
an air change within the house occurred every hour. Indications are
that the rate of air change in private housing is much less frequent
than once each hour. Longer periods between a complete air change would,
of course, increase the radon daughter exposure. In the U. S. such
exposure would be in conflict with the Federal Radiation Council policy.
By-product gypsum is a relatively water soluble precipitate. Sampling
of seepage from an Inactive gypsum pile shows that they continue to yield
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significant quantities of radium to surface streams and ground water
for years after the pile is abandoned. Because of the solubility of
the gypsum this problem is analogous to, but more critical than, the
problem of stabilization of uranium mill tailings.
Sampling conducted by the AEC and the Idaho Department of Health
(AEC, 1970) indicated that gross alpha concentrations in ambient air at
Pocatello, Idaho were approximately 15 times background values. Concen-
trations of polonium-210 (a radon daughter product) in Pocatello were
approximately 100 times background values. The AEC conducted limited
in-plant sampling in a thermal and a wet-process plant within the city
of Pocatello. The AEC concluded that approximately 9.8 Ci/yr of
polonium-210 were released to the atmosphere from the two plants. At
the PMC thermal plant concentrations of polonium210 were as high as
41.4 percent of the AEC limit while thorium concentrations of 3.25 times
the limit were reported from the J. R. Simplot Co. wet-process plant.
EPA is presently conducting mass balance studies within both of these
facilities to determine the magnitude and extent of possible radiation
problems.
EPA, Region VIII, (Lammering, 1972) has conducted a preliminary
mass balance of radiochemical material (polonium-210) primarily related
to air emissions from the Rocky Mountain Phosphate Plant at Garrison,
Montana. The plant processes animal feed supplements. The Regional
study tentatively concluded that approximately 10 percent of the incoming
polonium was released to the ambient atmosphere from the plant stacks.
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Thermoluminescent dosimentry (TLD) sampling by NFIC-D at two
Florida wet-process plants indicated that the radon-daughter concen-
trations were very low within the plants. Saroplinp, locations did not
include the plant stacks. Particulate analysis for polonium-210 was
not completed at the time of this report.
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V. TREATMENT TECHNOLOGY
WATER
Generally, the industry practice is to recycle water from the
gypsum pile for transport of gypsum from the pan filter and for use
in scrubbers and condensers. This contaminated water is the main waste-
water stream in phosphoric acid plants. During long periods of wet
weather many mills find it necessary to discharge excess contaminated
water to the receiving streams.
The treatment practice now under consideration as best practicable
technology by EPA consists of "double liming" of the excess gypsum pond
water before discharge. This procedure assumes the construction and
proper operation of a gypsum pile and recycle pond, with excess precipi-
tation as the only discharge.
The "double liming" process [Figure 5] is a two-stage lime neutra-
lization, with an end-point pH in the alkaline range. The treatment is
designed to precipitate fluoride and phosphate as calcium fluoride and
dicalcium phosphate, respectively. Geochemical literature, uranium-
milling experience and limited sampling indicate that "double liming"
to a pH greater than eight, while not specifically designed for radium
removal, will reduce radium to acceptable levels.
Two separate technologies exist to ensure that the gypsum pond
circuit achieves a negative water balance - that is, that gypsum pond
water is consumed, eliminating the need for any discharge. This is
accomplished by use of contaminated gypsum-pond water for sulfuric-acid
dilution, a consumptive use [Figure 4]. Such usage has the advantage
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DUST COLLECTOR
LIME
FEEDER
POND
WATER
a a
CM-Q CM-Q
i rn
IMILKOF
I LIME I
STORAGE-
JD
THICKENER
TO GYPSUM POND
CALCIUM PHOSPHATE
POND
TO RIVER OR
PROCESS UNITS
Figure 5. Flowsheet, "Double Limin^" jreatmant of "ypsurn Pond Water
(EPA, :IOV. 1373)
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33
of recovering additional phosphate that would otherwise be lost to the
gypsum pile.
"Both methods of accomplishing sulfuric acid dilution with pond
water are proprietary. One method is considered a trade secret. The
other is protected by patent. Either process can be added to existent
plants or included in the design of a new facility.
The trade secret procedure involves two points. One is the
mechanical means by which the dilution is made so as not to create a
pluggage problem. The second involves redesign of the phosphoric acid
reactor cooling system to remove the heat load formerly removed by the
sulfuric acid dilution cooler.
The patented process was developed and has been placed in com-
mercial operation.
It involves sulfuric acid dilution by a two-step procedure in a
manner radically different from current practice. The details of process
control, vessel design, and materials construction are all proprietary
information" (EPA, 1973).
Many plants, especially those in Florida, are located on areas
that are underlain by limestone. The acidic gypsum pond water can
react with limestone resulting in the development or enlargement of
cracks, caverns, and other solution features. This, in turn, permits
the movement of contaminated water into the ground water. Many plants
which report a negative water balance on the contaminated-water system
are actually discharging radioactive waste waters to aquifers.
Solution features located in the bottom of several water-storage
reservoirs have been filled with an impervious clay material to elininat
water loss to the aquifer. A wealth of experience has been developed
in other fields in the construction of impervious liners for ponds,
using material such as clay, plastic, or rubber. These methods are
directly applicable to the lining of gypsum ponds.
AIR (EPA, 1972)
Air pollutants from phosphate mining and millinp will arise from
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34
rock processing, phosphoric acid production and from fertilizer manu-
facture. Particulates generally arise from the mining, bulk handling,
benefication and product materials, while gaseous pollutants, parti-
cularly the fluorine compounds and sulfur and nitrogen oxides, evolve
from the acidulation and curing processes.
Little air pollution would be expected during the initial mining
and benefication processes where the ore is transported as a slurry.
However, subsequent drying and grinding can result in a major source of
particulate emissions. Gaseous radioisotopes would also be expected to
be driven off during drying. The following emission factors for parti-
culates have been estimated for this phase of the process:
Uncontrolled Emission
Process kg/metric ton
Drying 7.5
Grinding 10
Transfer and 1
storage
Open storage 20
(Ib/ton)
(15)
(20)
(2)
(40)
Control
Dry cyclone and
wet scrubbers
Dry cyclone and
fabric filter
Dry cyclone and
fabric filter
Efficiency
95-99%
99.5-
99.9%
99.5-
99.9%
piles
After grinding, phosphoric acid is produced either by the wet or
thermal process. In the wet process the major air pollutants are silicon
tetrafluoride and hydrogen fluoride. These may continue to emanate from
the gypsum ponds containing the process wastes in significant quantities.
In the thermal process the major air contaminant is phosphorus pentoxide,
P.O., as an acid mist in the absorber tail gas. Since the acid mist
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35
collection system is an integral part of the thermal process, emissions
below include this factor:
Emissions
Process
Wet
Thermal
Fluoride Particulate
kg/metric (Ib/ton) kg/metric (Ib/ton)
Source ton ton
Reactor 9 (18)
Gypsum 0.5 (1)
Pond
Condenser 10 (20)
Tower - - 2.3 (4.6)
Tower - - 2. ft (5.6)
Tower - - 0.9 (T .")
Tower - - 0.1-1.5 (0.2-3.0)
In the final phase of the process resulting in the phosphate
Control
Wet
Scrubber
-
Wet
Scrubber
Packed
Tower
Venturi
Scrubber
Electro-
static
Precipi-
tator
Mist
Eliminator
fertilizer
product both fluorides and particulates may be expected as indicated below:
Product
Normal
super-
phosphate
Triple
super-
phosphate
Emission ^
Particulates Fluorides
kg/ kg/
metric (Ib/ton) metric (Ib/ton)
Process ton ton
'Grinding, 4.5 (9)
drying
Main Stack - - 0.08 (0.15)
Run-of-pile - - 0.02 (0.03)
Granular - - 0.05 (0.10)
Control
Fabric
filters
Cyclones
and wet
scrubbers
or fabric
filters
Following control devices.
-------
36
These emissions result from granulating, screening and bagging of
the product.
The efficiency of air pollution control devices given above would not
necessarily apply to the radon daughter products since in many cases these
particles may be smaller than the particle size distribution for which the
equipment was developed. In addition use of radium-containing pypsum trans-
port water for wet scrubbers may result in the presence of equilibrium con-
centrations of radon in this water.
SOLIDS
The large piles of by-product gypsum in the vicinity of wet-process
plants continue to serve as sources of radium for years after the time
of abandonment as a result of wind and water erosion. Technologies are
available to stabilize this material and eliminate this source of radium
pollution (FHPCA, 1966). As a minimum, an adequate program of gypsum-
pile stabilization would consist of (1) grading to prevent ponding and
promote runoff, (2) sealing with any of a number of chemical sealants
to prevent infiltration, and (3) covering with soil to prevent erosion
and promote plant growth.
Fertilizer products have been found (Spalding, 1972) to contain
most of the uranium present in the phosphate rock. During 1972,
almost half as much uranium was present in fertilizer spread on fields
as was mined for uranium recovery. Solvent-extraction methods have
been proven (Kennedy, 1967) for recovery of uranium from phosphoric
acid. Installation of such equipment would eliminate the discharge of
uranium to the environment, and increase the nation's supply of uranium,
-------
37
a resource expected to be in short supply in the next decade (Finch,
et al, 1973).
The uranium-recovery techniques would not influence the amount of
radium present in the fertilizer product. While most of the radium
precipitates with the by-product gypsum, a portion of the radium is
present in the fertilizer applied to the nation's lawns and fields.
This is estimated to amount to as much as 500 Ci/yr of radium. No
practical technology is known for the removal of radium from phosphoric
acid or phosphate fertilizers.
-------
38
VI. SUMMARY AND CONCLUSIONS
As a result of reconnaissance studies conducted from August to
November 1973 and summarization and interpretation of previous
monitoring data, it can be shown that the mining and milling of
phosphate rock for phosphorous and phosphatic fertilizers constitutes
an important source of radium being discharged to the environment.
Numerous guidelines and standards for protection against radiation
are exceeded by these radium-bearing effluents.
Specific findings of this reconnaissance study include:
(1) A major source of radium contamination to the water environ-
ment results from the wet-process acidulation step used in
phosphate milling. At least 35 plants use this process in the
manufacture of phosphate fertilizer. Water contained in the
recirculatinp; gypsum slurry systems is radioactive [e.g.,
60 - 100 picocuries per liter (pCi/1)] exceeding by at least
two to three times the Atomic Energy Commission (AEC) standards
for discharge to an unrestricted environment. These waters,
at most plants, are discharged as overflow during extended
periods of wet weather, however, at three plants (National
Phosphate, Allied Chemical, and Freeport Chemical) in Louisiana,
no holding systems are reported to be employed and there Is a
continuous discharge of gypsum slurry to the Mississippi River.
These plants are located upstream of the point of intake for
the New Orleans water supply.
-------
39
(2) Samples of ground water collected during 1966 and 1973 in the
Central Florida mining and milling area showed radium concen-
trations in shallow aquifers as high as 79 pCi/1. These
aquifers are used for individual water supplies. The
limit recommended by the U. S. Public Health Service for
radium-226 in drinking water is 3 pCi/1. The AEG standard
for release of radium-226 to an unrestricted environment is
30 pCi/1.
(3) Mining of the phosphate rock in Florida does not result in a
significant discharge of radium to the water environment
except that slime pond breaks can result in a massive
release of soluble radium. For example, it is calculated
that the December 3, 1971 Cities Service Company slime pond
failure on the Peace River released over 16.5 curies of
radium-226 to the water environment. The Peace River con-
tained radium at levels more than twice those given in the
USPHS Drinking Water Standard one and one-half years after
the pond failure, as a result of leaching the radium from
the slime deposits.
(4) A review of available data indicates that significant quantities
of radon gas and its decay products are emitted in the thermal
process of phosphorus manufacturing. At least 10 plants in
the United States use this process. The majority of these
plants are located in Tennessee, Florida, and Idaho. At
Pocatello, Idaho, samples collected in 1970 showed that 9.8
-------
40
curies per year of polonium-210 were being discharged to the
ambient atmosphere. EPA is presently conducting total emission
studies at this location to determine whether hazardous con-
ditions exist. The effluent guidelines now under consideration
by EPA for waterborne effluents from thermal processing instal-
lations recommend zero discharge.
(5) By-product gypsum piles contain thousands of curies of radium-
226 in a readily leachable form. This material will continue
to be a source of radiochemical pollution unless adequate control
measures are instituted. Control measures involving stabili-
zation of these gypsum piles are practicable.
(6) Treatment technology, which will control other contaminants such
as fluoride and phosphorous, is available and will reduce radium-
226 from gypsum transport water to acceptable levels. This
technique involves the "double-liming" procedure. This is the
recommended technology now being considered by EPA as the best
pacticable for this industry. Alternative control measures per-
mit the development of a negative water balance within the plant
to eliminate the need for any surface discharge.
(7) Treatment technology now being employed to control air pollution
from phosphate mills may control emissions of radon gas and its
daughter products from thermal processing plants. However,
definitive results await the outcome of the ongoing EPA sampling
effort. At plants using the wet-process acidulation step of
manufacturing phosphate fertilizer, wet scrubber technology
-------
41
may not adequately control emissions of radon gas and its
daughter products since the scrubbers are fed with gypsum
transport water which already contains high concentrations
of radium-226. The extent of this problem has not been
measured at this time.
(8) Present practice in Europe and Japan utilizes by-product
gypsum in the manufacture of an inferior grade of wallboard,
used in building construction. This wallboard exposes inhab-
tants to increased concentrations of radon and its daughter
products. Research is underway which can be expected to lead
to similar uses in the United States. This practice would
increase the radiation exposure of the general public and, as
such, would be contrary to Federal Radiation Council policy.
(9) The International Commission on Radiological Protection, the
National Committee on Radiation Protection, and the Federal
Radiation Council proposals for radiation exposure protection
are "recommended guidelines." The only enforceable radiation
standards are those promulgated as a regulatory statute by the
AEC (10CFR 20). The statute applys only to AEC licensees.
The use of radioactive material, or other sources of radiation
not licensed by the Commission, is not subject to the
regulation. The enforceability of any radiation guidelines or
standards as related to the phosphate industry is questionable.
-------
42
VII. RECOMMENDATIONS
It is recommended that:
(1) The proposed treatment technology in the effluent guidelines now
under consideration by EPA for the Basic fertilizer Chemicals
Segment of the Fertilizer manufacturers Point Source Category
be implemented at the earliest possible time through the Mational
Pollution Discharge Elimination System [These guidelines were
proposed in the Federal Register of December 7, 1973]:
(2) Waste discharge permits issued to plants in this category require
that no plant discharge gypsum or untreated process water to
surface streams;
(3) Treated process water discharged from phosphate fertilizer manufac-
turing installations be limited to 3 pCi/1 of radium-226 to take
effect no later than July 1, 1977 as this level is achieveable
through implementation of practicable and demonstrated treatment
technology presently employed by the industry;
(4) All new plants be designed to eliminate the need for process-
water discharge, and all plants should implement process modifications
to eliminate process-water discharges as soon as practicable and
in no case later than July 1, 1983;
(5) The EPA immediately initiate an investigation to determine the
magnitude and effect of radium-226 in seepage of contaminated
water from gypsum ponds, and where these investigations indicate
substantial seepage of water containing radium-226 to aquifers,
-------
control measures, including lining of ponds with impermeable
substances * shall be instituted, with new plants employing lining
of gypsum ponds when dictated by geologic conditions;
(6) Regulations be promulgated to ensure that (a) all precipitates
from process-water treatment systems are placed on gypsum piles,
(b) upon abandonment, gypsum piles are stabilized to prevent
future leaching or erosion, (c) as a minimum, such stabilization
include grading to promote runoff and prevent ponding, sealing
to prevent infiltration, and covering with soil to permit vege-
tative stabilization, and (d) by-product gypsum be prohibited for
use as a construction material in confined areas;
(7) The prevalence of use of ground water containing radium concentra-
tions exceeding the PHS drinking water standards resulting from
phosphate manufacture be ascertained through appropriate investigative
procedures;
(8) Ambient and stack sampling for radon gas and its daughter products
be expanded to include wet process phosphoric acid plants in
addition to the present EPA sampling of thermal process plants,
and treatment technology be evaluated to determine removal effi-
ciency of radon gas and its decay products; and
(9) To ascertain the possible hazard to the general public from continuous
exposure to emissions of radium and its decay products as a result
of phosphate manufacturing, an investigation be undertaken to
evaluate the total dietary uptake of radium in persons living in
areas known to be influenced by phosphate manufacturing.
-------
44
REFERENCES
1. Atomic Energy Commission. 1970. Pocatello and Vicinity Environ-
mental Air Sampling Results - December 19G9 Through May 1970.
Idaho Operations Office, Idaho Falls, Idaho.
2. Bates, Robert L. 1969. Geology of the Industrial Rooks and
Minerals, p. 178-201, 430-431. Dover Publications, Inc.,
N. Y., New York.
3. Battelle Memorial Institute. 1971. Inorganic Fertilizer and
Phosphate Mining Industries - Water Pollution Control. Grant
No. 12020FPD. Environmental Protection Agency, Washington,
D. C. September.
4. Bureau of Mines. 1971. Radiation Monitoring. U. S. Department
of the Interior, Denver, Colorado.
5. Datagraphics, Inc. 1971. Inorganic Chemicals Industrie Profile
(Updated). Grant No. 12020EJI. Environmental Protection Agency,
Washington, D.C. July.
6. Environmental Protection Agency. 1972. Compilation of Air
Pollutant Emission Factors (Revised). EPA Report No. AP-42.
Research Triangle Park, North Carolina. February.
7. Environmental Protection Agency. 1972. Field Operations and
Enforcement Manual for Air Pollution Control, Vol. Ill: Inspector
Procedures for Specific Industries. EPA Report NO. APDT-1102.
Research Triangle Park, North Carolina. August.
8. Environmental Protection Agency. 1973. Proposed Criteria for
Water Quality. Vol. No. 1. Washington, D.C. October.
9. Environmental Protection Agency. 1973. Development Document for
Proposed Effluent Limitations Guidelines and New Source Perform-
ance Standards for the Basic Fertilizer Chemicals Segment of the
Fertilizer Manufacturing Point Source Category. EPA Report
No. 4401/1-73/011. Washington, D.C. November.
10. Environmental Protection Agency. 1973. Economic Analysis of
Proposed Effluent Guidelines - The Industrial Phosphate Industry.
EPA Report No. 230/1-73-021. Washington, D. C.
11. Federal Radiation Council. 1960. ''Radiation Protection Guidance
for Federal Agencies." Memorandum for the President. May 13.
12. Federal Water Pollution Control Administration (FWPCA). 196ft.
Disposition and Control of Uranium -lill Tailinan Piles in the
Colorado River Basin. U. S. Dept. of Health, Education and
Welfare. Denver, Colorado. March.
-------
45
13. Finch, W. I., A. P. Butter, Jr., F. C. Armstrong, and A. E.
Weissenborn. 1973. "Uranium.11 United States Mineral Resources.
Professional Paper 820, U. S. Geological Survey. Washington, D.C.
14. Habashi, Fathi. 1970. Uranium in Phosphate Rook. Special
Publication 52. Montana Bureau of Mines and Geology, Butte,
Montana. December.
15. International Commission of Radiological Protection (ICRP).
1959. Report of Committee II on Permissible Dose for Internal
Radiation. ICRP Publication 2. Pergamon Press, London, England.
16. Kennedy, R. H. 1967. "Recovery of Uranium from Low-Grade Sand-
stone Ores and Phosphate Rocks." Processing of Low-Grade Uranium
Ores. International Atomic Energy Agency. Vienna, Austria.
17. Lammering, Milton, W. 1972. Letter dated September 11.
Environmental Protection Agency, Denver, Colorado.
18. Lewis, Richard W. 1970. "Phosphorus." Bureau of Mines Bulletin
650, Mineral Facts and Problems, p. 1139-1155. Washington, D.C.
19. Manufacturing Chemists Association and U. S. Public Health
Service. 1968. Atmospheric Emissions from Tliermal-Process
Phosphoric Acid Manufacture. U. S. Dept. of Health, Educa-
tion, and Welfare, Raleigh, North Carolina. October.
20. Manufacturing Chemists Association and U. S. Public Health
Service. 1970. Atmospheric Emissions and Wet-Process
Phosphoric Acid Manufacture. U. S. Dept. of Health, Educa-
tion and Welfare, Durham, North Carolina. April.
21. McKelvey, V. E. 1967. Phosphate Deposits. Geological
Survey Bulletin 1252-D. Washington, D. C.
22. Menzel, R. G. 1968. "Uranium, Radium, and Thorium Content
in Phosphate Rocks and Their Possible Radiation Hazard."
Journal Agriculture Food Chemistry, Vol. 16, p. 231-234.
23. National Bureau of Standards. 1959. Maximum Permissible Body
Burdens and Maximum Permissible Concentrations of Radionuclides
in Air and Water for Occupational Exposure. Handbook 69. U.S.
Dept. of Commerce. Washington, D. C. June 5.
24. O'Riordan, M. C., M. J. Duggan, VI. B. Rose, and G. F. Bradford.
1972. The Radiological Implications of Using By-Product
Gypsum as a Building Material. National Radiological Pro-
tection Board Report 7, Harwell, Didcot, Berkshire, England.
December.
-------
46
25. Public Health Service (PUS). 1962. Drinking Water Standards.
PUS pub 956. U.S. Dept. of Health, Education, and Welfare.
Washington, D. C.
26. Ruhlman, E. R. 1958. Phosphate Eock, Part I: Vininc, Bencfi-
ciation and Marketing. Information Circular 7814. Bureau of
Mines. Washington, D.C.
27. Spalding, Roy F. 1972. "The Contemporary Geochemistry of
Uranium in the Gulf of Mexico Distributive Province.' PhD
thesis, Texas A & M University.
28. Waggaman, William H. and E. Robert Ruhlman. 1960. Phosphate
Rock, Part III: Processing and Utilization. Information
Circular 7951. Bureau of Mines. Washington, D.C.
29. Waggaman, William Henry. 1952, ''Phosphoric Acid, Phosphates,
and Phosphatic Fertilizers." American Chemical Society Monograph
34. Reinhold Publishing Corporation, New York, N.Y.
30. 10 CFR 20. 1960. "Standards for Protection Against Radiation."
25 Federal Register 10914. November 17. .
31. 10 CFR 40. 1961. "Licensing of Source Material." 26 Federal
Register 284. January 14.
-------
APPENDIX A
ANALYTICAL METHODS AND QUALITY CONTROL
-------
A-l
ANALYTICAL METHODS AND OIJALITY CONTROL
The methods used at NFIC-D in analvzina the samnles collected
for this renort were developed to overcome t!ie analytical inter-
ference caused by excessive amounts of sulfate in the water and
solid samnles, and to nenerally simplify the nrocedures. Historically,
several precipitations were used to remove isotonic interferences so
that samnles could be counted, usino planchet-countinn eouinment.
The radon emanation techninue used by !!FIC-D, however, is soecific
for radon: and when radon samnles are held for 3-4 hours before count-
inn only radon-222 is measured. Thus, these methods are snecific for
the determination of radium-226, the parent of radon-222, and only
require the complete dissolution of the sample while in the bubbler.
-------
A-2
A. ANALYTICAL QUALITY CONTROL DATA
Reolicate standards were analyzed at several levels usinn the
Barium conrecioitation method vieldinq the followinq results:
Standard
Concentration
Blank
0.976 pCi/1
9.76 pCi/1
39.04 nCi/1
ilumber
Samples
6
6
7
8
f^ean
0.036
0.952
8.79
35.76
1 -Si ana
0.025
0.045
0.61
1.004
95%
C.L.
0.05
0.09
1.22
2.01
The detection limit is defined as twice the backoround noise
(blank) standard deviation or 0.05 pCi/1 for liquid samples.
The above results indicate that in the ranqe of zero to about
20 pCi/1, the confidence level of the measurement is about +10%.
Above 20 pCi/1 the 95% confidence level improves to around +5%. The
95% confidence levels based on countinq statistics alone are about
1 - 2 % and thus contribute little to the precision of measurement.
In the various procedures used for the analysis-of Radium 22G
by radon emanation, the systematic error most likely to occur would
be to lose some radium durinn sample preparation, resultino in the
reportino of concentrations lower than true concentrations. At MFIC-
Henver, standards were added to actual samples resultinq in nercent
recoveries of 100 +_ 5%. Admittedly, liquid standard additions to
solid samples is not necessarily a valid means of snikinq, it is the
best that can be done, lackinq a solid standard. Solid snike material
should match the samnle matrix as close as nosssible and, since solid
sample matrices varv so much, a solid soike suitable for a ranne of
solid samples is impossible.
-------
A-3
Standard Additions
Sample Type
Solid
Liquid
Liquid
Liquid
Sample Cone.
51 pCi/n
0.98 pC1/l
8.0 nCi/1
100 oCi/1
Sni ke
97.6
0.976
9.76
97.6
Response
149
1 .90
17.0
202
% Recovery
100.3
98.3
95.7
102.2
Reolicate analyses of solid as well as licmid samples were
performed and results were obtained which were well within the pre-
cision of the method. As a further check on the confidence of the
methods erployed at NFIC-Denver, liquid and solid samples were split
with two other EPA laboratories that analyze for radium bv the radon
emanation technique. These laboratories were the Technical Sunport
Laboratory at MERC Las Venas, and the EPA Eastern Environmental
Radiation Laboratory in 'lontqomery, Alabama. These results are sum-
marized below:
Reolicate Samples
Sample
Type
Liquid
Solid
Liquid
Solid
Solid
Liquid
Liquid
Solid
Solid
Liquid
Solid
Liquid
MFIC-Values
First
92
25
97
48
23
.81
8.1
28
21
91
21
7.6
Second
90 (di
24
-
51
27
.98
8.0
31
23
100
28
-
HERC-Las Veoas
Hrst
rect) -
-
99
47
21
-
-
-
_
-
- '
8.1
Second
_
-
no
54
27
-
-
.
_
-
-
11
Val ues
Third
_
-
-
53
18
-
-
-
_
-
-
-
EERL
First
94
-
-
41
26
-
-
-
_
-
-
-
Values
Second
98
-
-
47
-
-
-
-
_
-
-
-
(Units of nCi/1 or pCi/o omitted for clarity)
Precision data for these results are not yet available; however,
the close agreements are indicative of adequate methods employed by
all three laboratories.
-------
A-4
3. METHODS
RADIUM-226 IN WATER
(from unpublished USGS method)
Principle:
Dissolved radium in water is co-precipitated with barium sulfate which
is then separated by centrifuging. The precipitate is dissolved in alkaline
DTPA, and transferred to radon bubbler tubes where ingrown radon is removed
by a helium purge.
Radon is allowed to grow in for a measured period of time after which
it is transferred to alpha scintillation cells by a second helium purge and
counted. Radium-226 concentration in the original sample is calculated
based on the radon-222 and daughter product activity making the appropriate
corrections for ingrowth and decay.
Reagents: (Use reagent grade chemicals unless otherwise specified.)
1) Barium carrier solution: 50 mg Ba++/ml; dissolve 75.81 g barium
chloride (BaC12) in distilled water and dilute to 1000 mis.
2) Sulfuric acid, concentrated.
3) Sulfuric acid wash solution: add 5 mis of concentrated ^804 and
3-4 drops of Triton X-100 to 4 liters of distilled water.
4) DTPA-TEA solution: dissolve 10 g of sodium hydroxide pellets in
a beaker containing 60 mis of distilled water and stir in cold
water bath until dissolved. Add 20 g of purified DTPA and continue
stirring until dissolved. Add 17 mis of 50 percent triethanolamine,
mix and dilute to 100 mis. Place in a teflon bottle and store in
the dark to prevent reagent decomposition and discoloration.
-------
A-5
5) Defoaming emulsion: Dow Corning Anti Foam H-10 emulsion; dilute
to approximately 4 to 5 percent solution with distilled water
before using. Other defoaming agents may be used provided they
contribute negligible Radium activity to the samples.
Procedure:
1) Place one liter of water into a 1500 ml beaker. If the sample
has not previously been preserved with 5 ml/1 concentrated HC1,
add 5 ml HC1 and stir.
2) Add 1 ml of 50 nig/ml barium carrier (Ba++) to the sample and
stir.
3) Cautiously, and while slowly stirring, add 20 mis of concentrated
sulfuric acid to each sample (Use of a 500 ml dispensing flask
fitted with a 20 ml delivery head facilitates the acid addition.)
Stir well after the acid addition. Allow barium sulfate precipitate
which forms to settle overnight.
*
4) Carefully remove the supernate by decantation or suction and
quantitatively transfer the balance of the supernate and precipitate
to a 40 ml centrifuge tube using a rubber policeman and small
quantities of dilute sulfuric acid-aerosol wash solution.
5) Centrifuge as necessary, decant and discard supernate.
6) Add approximately 10 mis of distilled water and 1 ml of DTPA
reagent to the precipitate in the centrifuge tube. (More DTPA
may be used with samples containing excess sulfate). Disperse
the percipitate in each, tube by using a wiggle plate mixer or an
ultrasonic unit. Place tubes in a wire rack and immerse rack and
tubes to a depth of approximately one inch in a boiling water bath.
-------
A-6
7) Complete dissolution should occur within a few minutes if the
barium sulfate "pellet" was adequately dispersed. Occasionally,
total volume in the centrifuge tubes may decrease by 4-5 mis
as a result of prolonged heating and the precipitate may not
dissolve. Addition of distilled water to bring the total volume
to approximately 20 mis (max.) plus additional re-dispersion and
heating will usually result in rapid dissolution of even difficultly
soluble precipitates. After the precipitate has dissolved, cool
the tubes.
8) Using a funnel with a fine tip, transfer the cooled solution to a
clean bubbler. Wash the centrifuge tube several times with distilled
water and add the washings and sufficient additional water to the
bubbler to leave approximately one inch of air space at the top.
Add 1-3 drops of defoaming emulsion to the solution in the bubbler
to minimize frothing during purging.
9) Attach stopcock and°"0" ring to bubbler using clamp, leaving outlet
stopcock on bubbler assembly in open position. Attach helium line
(3-5 psi) to inlet side of bubbler. Slowly open stopcock on inlet
until a stream of fine bubbles rise from the porous disc. Maintain
a steady flow of bubbles through the sample for approximately 20
minutes to completely sparge all ingrown radon from the solution.
Close inlet stopcock and allow pressure under porous disc to equal-
ize momentarily. Close outlet and record time. (Purge)
10) Use of a magnetic stirring apparatus and small stirring bar in the
bubbler assembly results in a mixing of the solution during sparging
and a more complete removal of ingrown radon.
-------
A-7
11) Allow from 3-14 days ingrowth time for radon-222, (samples
suspected of .high radium-226 values require shorter periods
of ingrowth), depending upon the radium-226 concentration in
the original sample, volume of sample used, etc.
12) Subsequent de-emanations: Set up bubbler as in step 9 except
outlet stopcock remains in the closed position at all times
until sparging assembly is prepared to transfer the radon-222
in bubbler into the scintillation cell. Attach bubbler to
drying tube with "0" ring and clamp. Evacuate sparging assembly,
including cell, with vacuum pump for approximately 1.5 to 2
minutes. Close stopcock at vacuum pump, turn pump off and
momentarily crack "0" ring connection to purge trapped air from
line and bubbler inlet connection. Clamp and allow system to
stand for approximately 2 minutes. If the system leaks, the
manometer meniscus will flatten or the mercury level in the
manometer will begin to fall. If the meniscus remains stable
proceed as follows.
13) Carefully open bubbler outlet stopcock until manometer begins
to fall (check porous disc for fine bubbles). Allow vacuum to
equilibrate slowly, (otherwise there is excessive risk of drawing
liquid sample into drying tube). Bubbling will slow appreciably
in a few seconds. Slowly open outlet stopcock completely. Then
continue with sparging by slowly opening bubbler inlet stopcock,
checking porous disc carefully for rising bubbles, (flow-rate
must be closely controlled again at this point, to prevent
-------
A-8
sudden surge of liquid into drying tube.) Allow pressure to
build up slowly, controlling manometer fall-rate to complete
sparging in 15-20 minutes. Close cell stopcock approximately
4 mm before manometer reaches atmospheric pressure to guard
against pressure leak from cell during counting.
14) Close down sparging assembly stopcocks from cell to helium inlet
line in sequence as rapidly as possible. Record time. Remove
bubbler from assembly quickly and crack outlet stopcock momen-
tarily to release helium pressure. If a re-run is necessary,
the bubbler can be de-emanated again after a sufficient ingrowth
time has elapsed.
15) Place cell in light-tight counting chamber (or other dark place
if counting chambers are not immediately available). Allow 3
to 4 hours for the ingrowth of short lived radon daughters in the
cells before counting. Count cells overnight (approximately 1000
minutes.) Counting of high count rate sample (50 cpm) should
be terminated at 5-10,000 total counts. All cells should be
evacuated and flushed several times to reduce the rate of back-
ground increase in the cells. Overnight counting of a high count
rate sample may raise a cell background to the point where it
is no longer useable for low level determinations. Cell backgrounds
should be 0.10 cpm or less. High count rate samples may be accurately
calculated at 10,000 total counts, regardless of counting time.
16) Dates, times, counts and all other pertinent sample information
should be recorded on data and calculation sheets.
17) Counting cell K-factors are determined as in Standard Methods
section 305.4a, 13th edition.
-------
A-9
FUSION DECOMPOSITION OF SOLID SAMPLES FOR
226Ra ANALYSIS BY RADON EMANATION (EXPERIMENTAL)
Apparatus:
1) Platinum crucibles (35 ml. capacity) and tongs
2) Fisher (i.e., Meeker type) burner
3) Muffle furnace (900°C. capability)
4) Steam or hot water bath
5) Ultrasonic cleaner
6) Centrifuge and centrifuge tubes (40 ml.)
Reagents:
1) Carbonate-Borate flux: weight ratio of 1 part Na2B407'10H20 sodium
tetraborate decahydrate to 4 parts Na2C03 sodium carbonate (anhydrous)
Mix dry components thoroughly.
2) Ammonium Carbonate (0.5%) wash solution: dissolve approximately
50 gr, of ^4)2^3 purified powder in de-ionized water. Dilute
to one 1 inter.
3) 6ft HC1
Procedure:
1) Weigh 4.0 gr. of carbonate-borate flux into 35 ml. platinum crucible.
2) Melt flux over Fisher burner and distribute on walls of crucible,
i.e., line the crucible with flux.
3) Weigh sample (up to 1.0 gr.) into tared coated crucible and add
4.0 gr. flux. Mix thoroughly with a stirring rod.
-------
A-10
4) Top off crucible with 1.0 gr. flux. Spread over mixture as a
"lid."
5) Fuse at 900°C. for 1 hr. in muffle furnace.
6) After cooling, remelt over Fisher Burner and coat crucible walls
with melt again.
7) After again cooling, fill crucible with (NH^C^ wash solution
and allow to stand overnight, preferably over hot water or steam
bath. Cover so the sample doesn't evaporate to dryness.
8) Transfer melt into centrifuge tube with (NH/^C^ wash solution
with aid of ultrasonic cleaner to break up the solid pellet.
9) Centrifuge, decant and discard the wash solution. Wash several
times. Use ultrasonic bath to break the "pellet" into finest
particles possible.
10) After final decantation, dissolve melt in 6^ HC1.
11) Transfer solution to "radon bubbler," as in Step 8 "Radium-226 in
Water" and continue with steps 9-17.
Additional Comments:
1) The (NH^^ wash is to wash out soluble sulphate salts which
would cause Ra-Ca to re-precipitate as sulphates after dissolution
of carbonate melt. The Ra-Ca carbonate is insoluble in the wash
solution.
2) If there is more than a few percent silica present in a sample it
may be necessary to evaporate the sample in a platinum crucible
with hydroflouric acid (15 ml per 1.0 gr. sample) before fusion.
High silica will cause a gel to form in the dilute hydrochloric
acid solution.
-------
A-ll
3) High sulfate samples (e.g. gypsum) cannot be quantitatively
analyzed by this method. Losses from 10% to 30% occur. An
alternate method for gypsum analysis for Ra would be to treat
a 0.1 - 0.5 gr. sample directly with an excess of sequestering
agent used in the "normal" water analysis.
Bibliography
Decomposition Techniques in Inorganic Analysis, by J. Dolezal, P. Povondra,
Z. Sulcek
English translation ed. by Hughes, Floyd, Barratt
London Iliffe Books, Ltd.
New York American Elsevier Publishing Co. Ltd.
-------
A-12
WET DIGESTION OF BIOLOGICAL SAMPLES FOR 226Ra ANALYSIS
BY RADON EMANATION
Apparatus:
1) 100 ml. beakers
2) hot plate
Reagents:
1) concentrated HC1
2) concentrated HN03
Procedure:
1) Place 5 gr. of suitably (see comments) ground sample in a 100 ml.
beaker. Add 10 ml. of concentrated HNOs and evaporate to near
dryness; if the residue is not white or very light colored, add more
HN03 and repeat evaporation.
2) Add 10 ml. of aqua regia (1 part HNOg + 3 parts HC1) and evaporate
to near dryness. Bring volume to 5 ml. with aqua regia.
3) Wash solution into radon bubbler with de-ionized water, seal and
begin ingrowth.
Comments:
1) Dissolution of samples which are particularly resistant may be
accelerated by adding (dropwise, slowly and carefully!!) a few
milliliters of 30% H202.
2) Oil drops may appear after dilution of final aqua regia solution
with de-ionized water. These may be dispersed with Triton X-100
or some similar detergent/solubilizer. This, of course, causes
-------
A-13
quite a bit of foaming during purging and deemanation. Add extra
anti-foaming agent and use a slower bubble rate.
3) After transferring the solution to a radon bubbler, the beaker
may be heated with 5 ml of de-ionized water and 1 ml of DTPA
solution (see "226Ra jn water") and rinsed into the bubbler.
4) A sample (e.g., edible portion of oyster) may be prepared by freezing
then grinding in a blender with dry ice. The dry ice is then allowed
to sublime in a refrigerator.
-------
APPENDIX B
DRAFT REPORT
ON
RADIUM-226 AND RADON-222 CONCENTRATIONS
IN
CENTRAL FLORIDA GROUND WATERS
BY
S. David Shearer
Bradford Smith
D. E. Rushing
-------
B-l
3Radium-226 and F.adon-g_22 Concentrations in
Central Florida Ground Waters
IITTEODUCTIOH
The Physical and Engineering Sciences Section, Technical Advisory
and Investigations Erancfr, FWFCA, Was requested by the Florida State Board
of Eealth to assist then in assessing the radius-226 and rodon-222 concen-
trations in central Florida ground waters, especially those areas around
the phosphate fertilizer plants.
The phosphate deposits are considered to be a potential low-grade
uranium ore, hence, the uranium concentration in the phosphate-bearing
formations is much higher than the natural abundance for all rooks. Addi-
tionally, all phosphate-ore formations are older than one million years,
end since the uranium is considez-ed to "be syngenetic, radium is expected
to be present in equilibrium amounts vith the uranium.
High radium concentrations have been found in both the finished
fertiliser and the vaste vaters in ponds adjacent to the plants. Process-
ing of the phosphate ore is expected to partition the uranium and radium
vith the radium being concentrated in the waste'products and the uranium
enriched in the phosphate product. Sampling and analysis have not been
made to confirm this supposition. However, disposal of liquid wastes
directly to the environment may ba nn immediate hazard and Icaching of
solid-waste spoil piles may be a long-term supply of radium pollution.
-------
B-2
Ground-water contamination is possible in Polk County and other
areas of central Florida, Most of the area is underlain by a surficial
cover of thin beds of sands, gravels, clay, and ir.arl of Pliocene to
Recent age. Underlying these younger beds is the Bone Valley Formation
and the Hawthorn Formation from which it was derived. Both are phos-
phoric but only the Bone Valley contains commercially ninable phosphate
ore. The Hawthorn Formation io a confining layer for the artesian water
in the "principal artesian aquifer" of central Florida. In this area the
top of the aquifer is the Tampa Limestone; this formation and succeeding
older fomations to as much as 1,500 fest below the land surface produce
i
copious aaounts of fresh ground^vater* Recharge to the artesianaquifer
is in areaq. north of Polk County where the aquifer beds are at or near
/
the surface. In Polk County local recharge occurs where sinkholes extend
/ ."
from the .surface through the Hawthorn Formation to the aquifer. It io
/ .. ;'
through such isinkholes that radiun polluted water nay enter the artesian
/ :
aquifer^ either by direct discharge into a sinkhole or by surface runoff
'V' / ;." ;
.or subsurface migration to a sinkhole.. Radium pollution that ha3 been
/ '!. 'I-
incorporated in the ground-water phase nay be discharged to ths marine
/ ;' i
environment by surface and submarine springs. Many larga springs have
/ ' i
: .'r / s '-
been;noted to the west and north of Polk County on land and off-shore in
the Gulf. '
During the period January 10 - 21, 1966, a number of ground-water
samples were collected in the central Florida area for radiochemical and
inorganic chemical analyses. The area covered in this ground-water
canpling extended in:.a north-south direction from C-roveland to Arcadia
-------
B-3
and. in an east-west direction from Kissiixsee to Tampa. Samples were col-
legted from the following counties: Be vSota, Hardee, Highlands, Hills-
borough, Lake, Manatee, Orange, Osceola, Baoeo,, and Polk. Ficure 1 shov,3
the general survey area and sample collection points.
Table I presents a summary of the various types of samples col- .
lected and a breakdown of tha 80 private veils which were compled. Of
the 105 individual veils sampled, depth vas not obtained on 29 of them.
Depth of the remaining wells ranged from 15 feet to l4oO feet. Approxi-
mately 1350 people were using water from tha 80-private veils sampled
end 157j300 people were using tha municipal veils sampled,
FIELD COLLECTION AND LABORATORY AIIALYSIS PROCEDURES
As it vas desired to analyze R-i-i samples collected for radon-222, -
special collection procedures were employed to ensure that this isotope
remained in solution. This vas done in the following manner. The faucet
at the veil or sampling point was turned on and allowed 'to run slowly for
a short time. A one-quart polyethylene bottle vas filled to overflowing,
the bottle squeezed .slightly while full and a screw cap tightened and
sealed vith black plastic tape. In this manner a slight negative pressure
existed inside the bottle and any leakage vas into rather than out of.the
»
vater, thus insuring minimum or no loss of radon from the sample. In
addition to the one-quart sample, two one-gallon samples were collected
at each sampling point. The latter provided sufficient sample for detailed
radiochemical and inorganic chemical analyses.
Upon receipt of samples in the laboratory, a volume of approxi-
mately 20 ml vas transferred from the quarto to a tared evacuated radon
-------
B-4
Table I
Sumnary of Typos._of Samplea Collected
25 Municipal Well Supplies
80 Privately O'.med Wells
64 Domestic Usa Only
6 Domestic plus Industrial Use
k Domestic plus Other Uses
2 Domestic plus Irrigation
k Industrial Use Only
1 Thermal Spring
1 Natural Well .,
2 RLver Waters
2 Industrial Waste Waters
bubbler which is shown in Figure 2. The bubbler was tlien weighed to
i
obtain a voluoa and the radon subsequently stripped from solution and
transferred to an alpha sensitive counting chamber by means of passing
aged compressed air through the saaple. The scintillation cell and the
cloenanation assembly are shown in Figures 3 and 4. The regaining irater
in the one-quart bottle v/as filtered through 0.5 aicron rasabrane filters,
tf
acidified, and placed aside for subsequent radium-226 dsterciination.
. A nuaber of the samples were selected for detailed radiochaniical
and inorganic cneaical analyses;
P.?.cion-222 and Radiua-226 Concentrations
, Table II presents a percentile eunciary of the radon-222 and
-------
CLERMONT
\OADE CITY
Loke County
r Polk County
\ J
WINTER
GARDEN 91
Q .92
Orange County
Oseeolo County
r^KISSIMMEE
9«
Posco County
ti2
JlPLANT
MULBERRYg * jijBARTOW
40 *n Ufzo
7./,*.,V5 .17^.'
floAVENPORTV
t/l/CF
ALFKE
AU8URNOALC
99 »... ^
03 j> J '
^FROSTPROOF
.41
.42
,j Ppjk Counljf
9i%BowLiNG GREEN" ~~ T"
I AVON
I PARXB/M
Hordee County
Oesolo County
1ARCAOIA 47
MUNICIPAL SUPPLIES
PRIVATELY OWNED
O 5 10
Figure I. GENERAL SURVEY AREA FLORIDA GROUND WATERS
-------
LIQUID
LEVEL
135 mm
l7mm
O.D
33 mm
TmmO.D.
"^35 mm*
«9-
CORNING NO.2
OR EQUIVALENT
-BUBBLE TRAP
7mm I. D.
-RIGIDITY BRACE
-7mm CAPILLARY TUBING
I 1/2 mm I.D.
-FRITTED GLASS DISC
10-15 MICRON PORES
-VOLUME TO BE KEPT
AT MINIMUM
Figure 2. RADON BUBBLER
-------
67 mm
90 mm
Phosphor
Coated
Clear Silica
Window
Y///////////////////;
50 mm
Corning No. 2
or Equivalent
Brass Collar
Kovar Metal
Figure 3. Scintillation Cell
-------
Scintillation Cell
/
1
^J>
1
V S/\
lf f ^ r
E
\
i
*
i'
:'
i
!
5
a
B
I J
J
1
^
Open End Manometer
j 1 1/2 mm 1. D.
* Capillary I tube
q I nermomefer uapniary
L
- ^ " Mnnyorous iviuyutibiuiii rci uuiui uie
^
i
(
<
i1 ^ ASCOT 1 1 s
ii
v Jy Air From Compressed
1 1 Air Regulator
1 o
cr
^ .«.. ._. _. ixuuon Duuuicr
XJ)
Figure U. De-emanr.tion Assembly
-------
B-5
Table II
Surjnary of Radon-222 or.d Radiun-226 Concentrations
(pc/l) in Central Florida Ground Waters
105 Drilled Wells
90$ samples
Radon
< 31*30
< i860
25$ < 260
RANGE OF CONCENTRATION 23 - 46,600
Radium
; -
RANGE OF CONCEIITRATIOII
< 9^60
< 2780
< 970
23 - hi
< l
o.o - 76
25 Municipal.Wells
RANGE OF CONCENTRATION
35 - 720
0.0 -
-------
B-6
radiun-226 concentrations found in ths well water samples. Tabls III pre~
cents a tabulation of municipal vail supplies with information on campling
cite, depth of -well, radon-222, radium-226, uranium, thorium, lead-210,
and polonium-210 concentrations. Table IV is a sumsiary of the 80 privately
owned vails. Table V is G summary of radon and. radium concentrations in
several miscellaneous samples which were collected. Tables VI and VII
present the inorganic chemical analyses from a. selected number of stations
for municipal and private vater supplies, respectively. All radon-222
concentrations have been corrected to time of sample collection.
Of the 105 well samples collected, 60 privately owned wells were
located in the central phosphate valley area. For purposes of this report,
this is considered to be the area bounded by Range 22 East (R22E), Range
27 East (R27E), Township 27 South (T27S), and Township 33 South (T33S).
The average radon concentration of the 60 samples in this area was ^950
pc/1 with a range of 76 "to U6,600 pc/1. The average radon concentration
for the 20 privately owned wells outside of this area was 1,100 pc/1, with
a range of 23 to 3,830 pc/l»
BITBRPKSTATION OF DASA
Tha interpretation of the data is limited as the study was first
dosigned as a reconnaissance of the radon and radium concentrations in
water supplies in and around the phosphate mining and processing areas.
Thus the study was Intended to be more heuristic than comprehensive. Row-
ever, a few conclucions can be cLravm from the data with reasonable accuracy.
At first glance of the data, there seema to ba no correlation
between the radon and radigm concentration. Any obvious correlation
-------
Table III
Sample Depth of
Karibcr rlonicipal Suirply Well (ft)
83 Bartovj Well Wo. 3
650
Dari;oT.,T (Treated) -
Ao ration, Filtration,
Chlcriuation
Qh Winter Haven Wells 1 and
2 (RAW) 1 - 593
2 - 816
il Well
Rn-222
260
80
20
95
60.
:35
560
140
480 .
Supplies - Central Florida
01*032
Ka-226 U a Th Pb-210 Po-210 Alpha
(pc/1) lES/1) (pe/l) (pc/1) (pc/1) (pc/i)
1.6 - -
1.4
0.67 - - - -
0.58 1.2 , 0.12 0.0 0.0 2.7
0.76 - - 0.2 0.1 3.3
0.47 - -
0.98 0.7 o.n 0.5 o.i 3.7
0.7 0.11 0.2 0.1 0.4
3.3 0.9 0.52 0.6 0.1 4.9
Gro.o:
Beta
(PC/:
2.7
3.2
3.7
3.8
24
85 Winter Ilavon Wells 3
4 (ll/\w) 3-648
4 - 640
86 Lal:o Wales Well 1,
Market St. Plant (RAW)* 1022
87 Lc&e Wales Well 1,
Grove Aye. Plant (RAW) 1063
83 Avon Park (RAW)
89 Scbrins Franklin St.
Well (KAW) 1430
90 Arcadia Well 1 (RAW) 495
Arcadia (Treated)
Aeration, Chlorination 210 2.5 -
(continued)
-------
-.-. .- ... ., - .. . ,-, -,
1
Municipal Well Supplies - Central Florida °°
Sample Depth cf
JT^bor Municipal Supply Hell (ft)
91
92
93
&
95
96
97
93
99
100
101
102
103
Eovlinc', Green r.t
Water i'arJ-:
Plant City Well 3
Plant City Well 2
Zephyrivills
Bade City Well 1
Clcnaont South Well
ClemoiYt Highland Well
La3:c Alfred Well 4 (RAW)
Lal;c Ali'red (Treated)
Aeration., Ciilorination
D-ojidee Well at City Park
Ualnes City Well 7
Hoinec City Well 8
Aubumdal^, Tampa St.
Well
Aiibumdale, Water
Plo.nt l.'oll
750
368
t
h2$
150
525
550
560
800
565
616
Rn-222
(pc/1)
260
150
360
360
305
600
720
220
50 :
560
125
115
110
85
Gross Gross
Ra-226 U a Th Pb-210 B>-210 Alpha Beta
(PC/1) .(MC/1) (pc/l) (pc/l) (pc/l) (pc/l) (pc/1)
2.7 0.9 0.15 0.3 0.3 2.fc 11
0.77' -
0.00 1.2 0.06 0.1 0.0
0.31 1.2 0.00 0.3 0.0 2.9
o.co -
0.39 -
0.29 1.8 0.0k 0.1 0.0 0.8
4.1
1.8 - - - ' -
0.0 - - 0.0 0.0 0.7 ^.3
. 0.7^ - -
0.73 -
0.50 -
°*53 - - - - /'nnnt.lT-irfll
-------
Table III (continued)
I-'Iunicipal Well Supx^lies - Central Florida
Gross Grosi:
Sample Depth of Rn-222 Ka-226 U - a, Th Fo-210 R>-210
Ilir.ibgr Municipal Supply Well (ft) (pc/l) (pc/l) .(|Jg/l). (pc/l) (pc/l) (pc/l) (pc/l) (pc/l)
104 Lakeland Well -
9 H. Florida Ave. 865 160 0.80 - - 0.1 0.1
105 Lakeland Well 22 89! 260,-. 0.04
106 Mulberry Well 1 770 165 0.45 ' .-1.4 0.06 0.4 0.1.
107 Hedula Recreation ....... .. . _
Ceirber - Ilorth of '
Mulberry 320 .0.23 - -.- --^-..... -
03
I
10
-------
Ta^lc IV
Privately Cfaned Wells - Cer.tral Florida
Sarrnle
7
8
Locution
Depth of
Well (ft)
II. W. 60 one mile vest
of Bartov, Polk County UOO
II. W. 60 tvo miles vect
of Barbou, Polk County 551
Ki(l;3G IToocl Rod and Gun
Club., 3 niles east of
1-Ii.a.bci-ry, Poll-; Co^jnty 1?0
300
II. U. 5'i3 five railes
H.E. of Mulberry, Pollc
Ccunty
E.U. 5l;OA one-half
mile couth of High-
lands City, Polk
Coiinty
1-1/2 Tjiilu's north of
Earbov, Polii County
H.W. 60 t'..'o miles
east of Bartow, Polk
County
II. W. IT one end -one-
half miles south of
Airba:;e, Foil: County
155
200
Ra-222
(pc/1)
76
680
2380
210
95
970
3060
1030
Ea-226
(pc/1)
0.03
1.86
1.71
0.48
U
(MS/1)
a Th
Fo-210 Fo-210
(PC/1)
0.7
2.18 1.5
0.69
0.01
0.0
0.74
0.0
0.0
0.1
D3
I
Gross
12
Beta
IP2/1]
(continued)
-------
S.-jnple
10
11
12
13
Table IV (continued)
Privately Owned T7ells - Central Florida
Location
Depth of
Well (ft)
II.W. 1? one mile
couth of Airbase,
Polk Co-nty
II.W. 60 two miles
east of Mulberry,
Folk County
Internetlonal Min-
erals Cl;.c.-:.iical Co.
(Connie: Plant),
Poll: County
0.1 ailcs east of
Bonnie Mine Pd. on
Pebble-aolc M., Polk .,
County
Ik 1/2 rale vest of CCA
15 on FcVoledale M.,
PoU: County
1 16 H.W. 6'tO at Jet. S.R.
555, Polk County
17 Bartov, 060 Herner St.
PoU; County
35
900
60
Rn-222
(pc/1)
3550
32^-0
860
3890
990
3,200
1010,
Ra-226
(pc/D
0.61
o.ko
0,12
2.35
0.21
1.19
u
0.9
0.1
a Th
0.33
0.06
Gross Gross
Pb-210 Po-210 AlT)lia Let a
(jpc/1). (pc/1) (pc/1) (pc/1)
0.6
1.2
0.1
13
0.9
(continued)
co
-------
Table IV (continued)
Privately Owned Wells - Central Florida
Sample
ri'u'iiber Location .
Depth of
Weil (ft)
Rn-222 Ea-226
(pc/1) (pc/1)
U - CcTh
.fes/il IRC/I}
GrOES
Fb-210 Po-210 Alpha
(pc/1) (pe/i) (pc/1)
Gros;
Eeta
18
19
20
22
23
International Min-
erals Cuenical Co.,
Koralyn Plant, Polk
County
Ilor:ielp.na ra. 1-1/2
nilcs norr.h of Home-
land, Polk County
One nile south of
BartO'.r on Homeland
RcU, Poll: County
II.W. 17. 1-1/2 railes
south of Eartov, Polk
County .«
U.W.17. 3 miles
south of Bartov, Polk
County
II.V. 555- One mile
south of intersection
of II.vr. 555 ?nd II.W.
640, Poll; County
92
98
200
89
160
Co. Eaat Deep
Well, A^ricola, Florida,
Folk County 800
8370
^730
4l60
.4190
5600
70 46,000
2.70
4.21
l.l
1.04
1.99
2,2
1.2
1750
1.89 0.4
1.14
0,03
0.00
0.03
O.S
0.5
3-4
0.2 10
0.2
ro
i
ro
14
10
16
(continued)
-------
Table IV (continued)
Privately Owned
SrjTple
JMuncer
25
26
27
23
29
30
31
32
33
34
Depth of
Location Well (ft)
Swift Co. well B-3, one
mile xrect of Swift Co.,
Polk County 1100
Minute Maid Co., two
miles vest of Agricola
Off Be vis Ed. two miles
vest of Ft. Me ode, Polk
County 105
Esvlc ML., 2-1/2 miles
vest of Ft. Meade, Polk
County
II. W. 17, 1/2 mile north of
Ffc. l-feado, Folk County* 97
II. W. 17, 1/2 mile north of
Ft. Meade, Polk County 187
Homeland, Folk County 105
Homeland, Polk County -
Hoinolond, Polk County . 88
Rn-222
(PC/D
2000
28,800
5730
22,700
9750
10,850;
4480
4130
2310
Wells - Central Florida
Ka-226 U
(PC/D (Pg/D
1.78 1.4
49 11
5.2S
76 4.2 '
0.21
5.13
2.68
2.41
2.15
a Th
0.04
0.37
'
0.58
Gross Gross
Fo-210 Po-210 Alpha Beta
(pe/1) (Pc/l)
0.3
7-6
3.7
0.0
1.5 75
0.8 97
16
194
(continued)
CO
co
-------
Table IV (continued)
03
I
Privately Owned Wells - Central Florida
Ssnple
Kuniber
35
36
37
33
39
Location .
Durant Section -
Eurant Ed. at Turkey
Creek, Ilillsborough
County
Intersection of H.W.
6^0 and Iconyon Rd.,
County
Depth of
Well (ft)
201
H.W. 60, 6 miles vest
of Mulberry, .llills-
"ooroush Cciuity
S,I\. 60 and Coronet
ivd., 4-D./2 miles %rest
of Mulbcii-y, Poll-;
County
II. H. 60,. 3 miles T/est
of Mulberry, Polk
County
2 nilcs east of Mulberry,
Folk County
90
150
200
96
96
Kelly KU and H.W. 27A,
1 r.iilc coutii of Frost
Pi-oof, Folk County 105
Rn-222 Ra-226
(pe/1) (pc/1)
i860
2490
3040
6270.
3350
4260
1.11
3.84
0.16
0.02
3-9
U
(US/1)
a Th
2.4
0.08
Gross
Fb-210 Po-210 Alpha
(pc/1) (P2/1) .(pe/1)
0,6
0.3
0.2
0.1 10
0.1
0,1
1.0
Gross
0.0
(continued)
-------
H.W. 27, 7 miles
GOuth of Sebring,
Iligl-ilcuido Comity 69 23
Grascy Lake, one nile
north of intersection
of H.U. 27 and H.W. 70,
Ilir^ilaiadG County ,t 46 76
Table IV (continued)
Privately Owned Wells - Central Florida
Grose Grcs.-
Sa-aplc Depth of Rn-222 - Ra-226 U a Th Fb-210 PD-210 AlpLis. Beta
lairibor Location . Well (ft) (pc/l) (pc/l) (pg/l). (pc/l) (pc/l) .(pc/l). (pc/l)
42* H.W. 2?A, 2 niles
coutii of Froct Proof,
Poli Coimty 37 25 1.2
^S* H.W. 27A, 3 miles
north of Ssbring, ' ,'
KifjlilaiidQ County 300 3830 2.3 - - 0.2 0.2 5 13
46* n.W. 60, 2.5 ni
VCDt Of D^GOtO- :
IliClilands County
line - 1250 0.67
47-* Intersection of H.W. 70 '
£uid H.W. 760 east of
Arcadia, Decoto County 263 3500 8.4 0.9 0.08 0.4 0.1 20 4$)
43* Broutivillc, Do soto County - 1100, 1.22
(continued)
00
i
-------
Table IV (continued)
Privately Owned Welle - Central Florida
Sample
Kmrfber
49
50*
Depth of
Location . Well (ft)
H.W. 17, one mile
north of Wanchula.,
Ilardee County 85
H.W. 39, at Crystal
Springs, Paoco County 36
Rn-222 Ra-226
(p=A) (pc/1)
UYO 0.82
Gross
U a Th Pb-210 Po-210 Alpha
(re/1) (pc/1) (pc/1) (pc/1) (DC/I^
0.8 0.09 0.1 0.1 2
Gross
Beta
(pc/1)
in i . '.
13
03
I
H.W. 50, 2 railes east
of Winter Garden, Orange
Count
52* H.W. 439S, I.k miles
couth of II. W. 50, Orange
County . -
53* H.W. 17, 2 miles couth.,
of Kiscirrnee, Osceola
County 60-70
H.W. 17, 5 miles south
of ICissimee, Osceola
County 90 - 115
55* II.W. 17, couth of
56
Kissiirjueo, Osceola
County 7^4-
1.5 r/JLlcs vest of Haines-
City off II.W. 92,Polk Co. 200
365
2780
153
870
1350
23^0
0.49
2.33
2.17
0.43
3-9
0.1
0.0k
0.0
0.1
(continued)
-------
57
Table IV (continued)
Pr.ivc.tcly Owned Wells - Central Florida,
Location
Depth of
Well (ft)
3.5 niles east of Lake-
land oIT H.W. 9?-, Folk
Co:uity 162
3.5 rails s east of Lake-
IcoicL off II.W. 92, Polk
County
2.5 miles east of Lake-
land of i' II.W. 92, Folk
53
Rn-222
(po/1)
i860
2610
60
61
County 150
II.W. 5-':2, one mile east
of Lake-land, Polk County 2f
Intersection of Fields Rd.
6210
10,000
and H.IJ. 5^2 east of Lsi:e-
laricl, Polk CoBnty 287 3810
62 Old Auburr.dale M. k miles
ea:;t of Lalcelond, Polk
County 120 2i)-10
63-:'- II.W. 92, 1.75 miles vest
of Plant City, Hills-
borou-^Ii County 13^ 550
6V* II.W. 92, 2 niles east of
H.W. 579, Hillsborougli
County 150 214-0
Ra-226
(pc/1).
2-7
0.75
1.20
1.89
3.58
0.03
0.02
u
(pg/1)
a Tii
(PS/I)
O.o4
Gross Gross
Pb-210 Po-210 Alpha Beta
(rc/i). .(PC/I)
0.7
1.9
0
C3
I
(continued)
-------
Table IV (continued)
Privately Owned Wells - Central Florida
Sample
ITiurfbor
65*
66*
67*
Location
Depth of
Well (ft)
70
71
Intersection of II.W. 301
Gild Pain rdver Ed.,
Eills"borou£h County
I\iver Vieir, Hillsborough
County
JI.W. 301, .75 mile south
of Alt-Tin River Bridge,
ugh County
K.W. 301, 2.5 miles
south of RLverviev,
Ilillc'bo.rough County
96
II.W. 672, 2 niles vest»
of Picnic, Hillsborough
County 187
Intersection of H.W.
672 CL-d H.W. 39 at
RLcnic, HillstorouGa
County
Intersection of H.W.
and K.W. 39 at Ft. Lone-
sor.i3, Hillsborougli Co.
Rn-222
(pc/D
2020
750
734
630
3400
,?
7650
Ka-226
(pc/1)
0.46
0.30
1.93
1.73
0.32
0.28
2650 .- 0.33
U
(ug/1).
0.8
a Th
o.o4
0.01
Gross
Fo-210 Bo-210 Alpha
(pc/1) (pc/1) (pVl)
0.2 0.1
0.6
0.1
0.4
CO
I
00
Gross
Eeta
i^Zi]
6 o
0.3 0
(continued)
-------
Table IV (continued)
Privately Owned Wells - Central Florida
Gross Crocs
So-imle Depth of Bn-222 Ra-226 U a Th Fb-210 Po-210 Alpha Beta
IIui.ibsr Location Well (ft) (pc/l) (pc/l) (ng/1) (pc/l) (pc/l) (pc/l) (pc/l) (pc/l)
72 H.W. 630, 1.7 miles
vast of Armour Ft.
Mcaue, Polk County 143 11,300 7.4l 1.6 O.OU 1.3 0.3 12
73 h nileo couth of
llyJLtGii-y on II.W. 37,
Poll: Coimty 200 5120 2.lit- 1.4 0.11 0.3 0.2 -
7h Bradley Jet., 6.5
jnilcc couth of Mul-
bcrry, Poll; County 183 7330 3-90
75 Bradley Jet., 7 miles "'
couth of Mulberry,
Poll: County - 2070 0.11 1.4 0.03 0.4 0.1
.*
76 One rale couth of
Bradley Jet., Polk
County 80-90 9460 4.32
77 Intersection of nev
cuid old II.U. 37, .
Poll; County - 3300 " 1.31
73 Old II.W. 37 south Into
Bradley Jet., Folk Co. 15 7600 19
(continued)
CO
I
-------
Table IV (continued) -
.... . . . ro
i
Privately Owned Veils - Central Florida o
Gross Gross
Scr.ple Depth of Rn-222 Rar-226 U . G Th Fo-210 Po-210 Alpha Lota
Kuriber Location Veil (ft) (pc/l) (pc/l) (pg/l) (pc/l) (pc/l), (pc/l) (pe/l) (pc/l)
79 Bradley Jet., Polk Co. - 1480 1.31
80 Rollins Mills, Polk '
Comity . 6550 2.3 l.k 0.04 0.7 0.3
81 Oalz Terrace, Polk Co. - 8680 IK6
82 OeJt Terrace, Polk Co. - 8^30 0.0
* Considered outside of area*
-------
B-21
Table V
Miscellaneous Samples
Ra-222 Ra-226
Sample De sc ript ion (pc/l) (pc/l)
Lithia Springs - Thermal Springs 2360 0.65
Mafia River - State Route 6^0 at
Bridge (State Sampling Point Ak) ^5 . o.21
Cynnimid Slimes Band Water .12 0,17
Natural Well - Highway 6kQ at Bridge
ever South Fork Alafia River 300 2.05
International Minerals Corporation
Gypsum Rjnd Water (at Spillvay) 2^0 112.90
Peace River at Saddle Creek 20 0«65
-------
Table VI
Inorganic Chenical _Analyses, pra: - Municipal Supplies
Sample
f Umber
05
83
93
94
97
99
7-7
7.6
7.6
7-5
7.4
7.9
ac CaCO
110
70
160
108
73
104
Nitrate
Hitrogcn
0
0
0
1.6
1.2
_
Total
Hardness
120
88
174
109
88
112
Conduc-
tivity *
120
75
.165
120
96
110
Total
Hiosphate
0.03
0.15
0.29
0.26
0.41
0.23
Sulfate
10
2.0
3.0
5.0
3-0
4.5
Total
Solids
184
98
114
324
144
164
Fluorides
0
0
0.4
0
0
0.3
CO
I
Dlhos at 25°C
Op
-------
Table VI
Inorganic Chemical Analyses, pjn -
Eanple
IIur.il-.cr
4
8
10
16
18
22
23
25
26
29
33
39
40
43
^^ Nitrate
-oil asCaC03 Nitrogen
7.7
7A
4.1
6.3
' 7.3
7.5
6.3
7.8
4.7
5.1
7.9
6.9
7-U
7.1
82 0
246 0
0 7*1*-
18 0
78 o
136 2.6
20 0
224 s 0
4 26.0
4 16.0
166 0
44 4.0
184 0
78 . 0
Total
Hardness
91
260
60
26
83
164
23
224
369
179
179
57
8
60
Conduc-
tivity *
83
230
no
46
33
175
41
220
520
215
160
60
200
60
Privately Owned Wells
Total
Phosphate
0.07
0.17
0.03
2.8
0.12
0.44
'2.6
0.03
0.28
0
0.13
0.50
0.13
0.40
Sulfate
U.5
10
4.5
15
2
72
15
*-5
. 220
120
1.5
5-5
3
2.0
Total
Solids Fluorides
120
324
150
90
112
242
120
33^
952
363
220
124
294
103
(continued)
0.5
0.7
0.1
0.5
0.4
0.3
0.3
1.0
1.2
1.2
0.1
0
0.3
0
CO
i
ro
CO
-------
Table VII (continued)
CO
1
ro
JS.
Inorganic Chemical Analyses, ppa - Privately Otmed Halls
Nuribcr
47
49
52
60
69
70
71
72
__TG_
7.3
7.6
7-5
7.3
7-7
7-9
6.7
7.3
Tss;y
172
124
120
188
143
93
42
173 ,
llitrate
Hitrocen
0
0
0
M-
0
0
0
0
Total
Hardness
200
75
112
200
143 ;
117
29
169
Conduc-
tivity *
215
102
.120
200
135 :"
90
. w
155
Total
Pnosphate
0.13
0.61
0«4l
0.16
.... o.o?
0.15 ~-:^
* 4.10
0.27
Sulfatc
4.5
1.5
2.0
4.5
:: 7.5-,..
- 4.0
5-0
3.0
'" -Total
Solids
124
134
98
270
168
106
96
238
Fluorides
1.7
0.4
0.2
0.2
0.3
0.6
0.6
0.4
nhos at
-------
B-25
irj masked by the extrezne ranges of the concentrations, particularly the
radon concentration* However, if the radon and radium concentrations are
ranked in r. decreasing order, and a Spearman's rank-ordar correlation
P (Rho) calculated, rn observed value of OoVf for 100 pairs of data
(private and municipal water supplies) ie obtained. At the a *= 0.001
critical level for N := 100, the upper liiait due to chance la 0.321. Thus,
it can be seen from this test that there io a definite, although Blight,
correlation between th2 radon and radian levels.
Secondly, are the observed radon and radium levels in untreated
water supplies outside the active raining area different froia the observed
levels within the area? Agaiia o. casual glance does not confirm or deny
this.
i
If, however, ve again ranli the sample values collectively in a
decreasing order (ML to 1L,) and apply the Wilco:con equation to test
> J* X
whether or not the tiro groups are front tha same population or tv/o dis-
tinct populations, a Z-statistic can be calculated from the equation:
ZRn, -
l -r 1)
V i 12
where n.. =i Number of samples outside the area
n0 K Jrumber of samples inside the area
Iv, = nn -h n0
j. i. ^
-------
B-26
£Rn = Sur.nation of the rani: position of the samples outside the
area,
we observe a 2^226 " 1»3> ZR:1222 a 3«7»
Comparing 'theGO calculated values to a Z-statistic table, it can be
pp^C
shown that tha Ra concentrations in the water samples "between the two
areas are not significantly different at the 95$ confidence level (a a 0.05)
226
This, however, does not imply that the Ra concentrations in the earth
aro statistically equivalent. On tha contrary, since tha Rn concentra-
tions in the water samples are significantly different at the 95$ and even
at the 99.9$ confidence level and since radon, an inert gas, is readily
226
soluble in water whereas its precursor, Ra , is probably so chemically
bound as to be relatively insoluble, it can be concluded that higher Ra*
deposits coincide with enriched phosphate deposits.
The Federal Radiation Council (FRC) has defined ranges for total
226
daily Ra *" intake and recommended countenaeasures. These are;
Range I - 0-2 pc Bsriodic confirmatory surveillance
Range II 2-20 pc Quantitative surveillance and routine
control
Range III - 20-2OO pc Evaluation and application of additional
control measures.
Assuming a 2-liter daily intake of water, a water supply whose Ra
concentration is 10 pc/1 would place an individual at the upper limit of
OO(C
Range II, disallowing any other ingestion of Ra from other sources (food,
air). The Public Health Service Drinking Water Standard hac been cat at a
value of 3 pc/1.
-------
B-27
Reviewing the data, two raonicipal vater supplies are above tha
3 pc/1 level but below 10 pc/1. In the case of the privately owned wells,
12 wells are greater than 3 3?c/l and less than 10 pc/1; three wells are '
greater than 10 pc/1 (19, ^9,. and 76 pc/l) .
It should be pointed out that at present there is no accepted ctand-
222
ard for Rn in water. A nunber of workers have. addre seed themselves to
the question and have suggested possible maximum permissible concentrations
222
for Rn in water.
The Maine State Department of Health and Welfare, after reviewing
several articles on this subject, established tentative guidelines for per-
nlssible concentration of radon in water to be used until a firm standard
is sejlr. Thase guidelines are 100,000 pc/1 occupational dose, 18,000 pc/1
for an individual in the population, and 16,000 pc/1 for public vater
supplies. The above figures are about 10$ lower than those suggested by
Hursh and co-workers.*
Only four privately owned wells are above this 18,000 pc/1 Rn
whereas no municipal wells even approach this figure. Aaratio;i would Sub-
stantially reduce the radon concentration by approximately 50-75/a to
within these guidelines as deduced from the data given in Table III,
Sample Uunbers 83, 90, and 98.
Radon values should be evaluated in terms of sample collection tech
niques. Radon values for punped veils probably have little interpretive
* Huroh, John B., et al. Health physics, Vol. 11, p. 1*63-76 (1965).
-------
B-28
significance; however, cuch values inay b2 useful for rapid reconnaissance
of many veils over a large area to identify those veils that should be
sampled for radium analysis.
Ill regard to the chemical constituents of the water, none of the
determined elements exceeds the limits set forth in the Public Health Ser-
vice Drinking Water Standards,
Recommendations
As a result of the study, the following recommendations ore submitted:
1. That the recommendations set forth by the FRC be implemented; that
PP/T
is, ftit veil waters used for domestic consumption whose Ra con-
centrations range from 1-10 pc/1 be routinely monitored* All
wells above 10 pc/1 should be routinely monitored and corrective
action taken, to decrease the level to within Range II, and hope-
fully to within Range I of the FRO.
2, Wells previously showing high radium, concentrations should be
resampled and efforts made to identify the aquifer supplying water
to them.
i
!
3. In some areas of Florida, ground---waters contain excessive radium
! -.
with respect to parent uranium. An effort should be nade to
determine if a natural disequilibrium exists in the "principal.
artesian aquifer" and-if so, the degree, £3termination of the
natural background disequilibrium will pc-iTiit identification, of
water to which excess radium has been added frca outside sources»
-------
B-29
h, Tha chartictsristics of the ef fluent s fro:?. the fertiliser industry
should be determined and a radiiua and uranium "balance should be
done for plant operations. Surface-voter courses near the plants
«
und ground-water for all nunicipal veils down the hydraulic
gradient, fron tho plant should be sampled and analyzed also for
radiun and uranium.
226 ?22
Ra and Rn" concentrations in vater supplies, both municipal and
private, vere determined in and around the active phosphate iaining area.
A correlation betveen radon end radium concentration does exist but is
yet eripiricEU.y undefined. The rtidon concentrations in \/ell v;ater outside
tho phosmate nining area are lover than those within the area, Eocon-
mendations for further study have been incorporated.
------- |