Occurrence of Strontium 

in Natural Water

GEOLOGICAL SURVEY 

CIRCULAR 420

Prepared-cm behalf of the U.S. Atomic Energy CommissSBlPknd published 

with the permission of the Commission
Occurrence of Strontium 

in Natural Water

By M. W. Skougstadt and C. A. Horr

Prepared on behalf of the U. S. Atomic Energy Commission and published with the permission of the Commission

GEOLOGICAL SURVEY CIRCULAR 420

Washington, D. C. 

1960
United States Department of the Interior

FRED A. SEATON, SECRETARY

Geological Survey

THOMAS B. NOLAN, DIRECTOR

Free on application to the U. S. Geological Survey, Washington 25, D. C.
CONTENTS

Page Page

Abstract...................._..._... 1 Strontium content of water.............. 2

Introduction........................... 1 Surface water ........._............ 2

Analytical methods .................... 2 Ground water ....................... 5

Sampling program__................_ 2 References _.._._._.................. 6

ILLUSTRATIONS

Figure 1. Map of the United States showing concentration of strontium in surface water

at selected sites.........._.......................__.........__.__._._.._.. IV

TABLES

Table 1. Concentration of strontium in surface water.__..._._....__...................._. 3

2. Maximum concentration of strontium in ground water ............ .-.,-..-,--..--.--. 6

III
EXPLANATION

O 

Less than 0.50 ppm

0.5 to 1.5 ppm

 

More than 1.5 ppm

Strontium zone boundary

22

Sampling site number

Figure 1. Map of the United States showing concentration of strontium in surface water 
Occurrence of Strontium in Natural Water

By M. W. Skougstadt and C. A. Horr

ABSTRACT

The regions where the stable strontium content of surface 

waters is relatively low (less than 0.50 ppm) include the 

Pacific Northwest, Northeastern United States, and the 

Central Lowlands, Particularly the Lower Mississippi basin 

and the Western Gulf Coast area. Moderate concentrations of 

strontium (0.50 to 1.5 ppm) are found in streams of Southeastern United States, most of the Great Plains Region, the 

Western Mountain and Plateau Regions, and California. 

Relatively high concentrations of strontium occur in the supface Waters of an area that includes Northern and Western 

Texas and Southern New Mexico and Arizona. Exceptions to 

the above distribution are due to local geologic conditions.

INTRODUCTION

Few data are available on the occurrence of 

strontium in natural water. Odum (1951) determined the strontium content of certain 

Florida waters. Alexander, Nusbaum, and 

MacDonald (1954) measured the strontium 

content of the public water supplies of many 

of the major cities through the United States. 

Nichols and McNall (1957) determined strontium in 380 municipal water supplies in Wisconsin, and reported results for about 100 

which contained more than 1.0 ppm (parts per 

million). Blanchard, Leddicotte, and Moeller 

(1958) have analyzed the drinking water of 

seven major cities of the United States by a 

neutron activation method and have reported 

their strontium content. These four reports 

contain about all that is known about the general distribution and occurrence of strontium 

in fresh water of the United States. This is 

somewhat surprising consider ing the fact that 

the concentration of strontium in sea water 

(13 ppm) exceeds that of any other cation except the four most common cations: sodium, 

magnesium, calcium, and potassium.

Certain features of the chemistry of strontium make it easy to understand the lack of 

available data on strontium occurrence in 

fresh water. Strontium is present in nearly

all fresh water but generally only in trace 

amounts (1.0 ppm or less). Because strontium closely resembles calcium chemically, 

and because it is present in much smaller 

amounts than calcium, the determination of 

strontium is a difficult analytical problem. 

The usual analytical procedure for calcium 

includes any strontium present as a part of 

the reported calcium. Thus, the analytical 

result for calcium is in error unless strontium is determined and a correction made for 

the amount of strontium present. The two 

elements are so similar in chemical behavior that there is no real need for determining both strontium and calcium, as far as 

ordinary water use is concerned.

Within recent years, there has been an increased interest in strontium and its occurrence and distribution in nature because of 

the public health hazards of the radioactive 

isotope, strontium-90. This isotope, a fission 

product, has become widely distributed over 

the earth in minute amounts by nuclear test 

explosions. Strontium-89 is also produced 

by nuclear fission. However, its half-life 

(54 days) compared with the half-life of strontium-90 (28 years) is so small as to make 

its potential hazard to life almost negligible. 

Natural, nonradioactive strontium isotopes 

are possible diluents for the harmful, radioactive isotopes when ingested by animals and 

by man.

Because of the lack of data on the distribution of natural strontium and because of the 

current interest in the physiological behavior of strontium, this project was started in 

October 1957 to survey the occurrence and 

distribution of stable strontium in natural 

water of the United States, and to develop an 

analytical method, or methods, which could be 

used for the routine laboratory determination 

of strontium in water.
OCCURRENCE OF STRONTIUM IN NATURAL WATER

This study is being made on behalf of the 

U.S. Atomic Energy Commission and is being 

carried out under the general direction of 

S. K. Love, U. S. Geological Survey.

ANALYTICAL METHODS

As an early part of this investigation, an 

intensive search of the literature was made 

for analytical methods applicable to the de - 

termination of strontium in natural water. 

The methods reported in publications indicated that either a flame photometric method 

or a spectrographic method would satisfy the 

requirements of the present project. These 

techniques are adequately sensitive and accurate, and also sufficiently rapid so that many 

samples can be analyzed.

The literature survey and comprehensive 

bibliography was submitted as an initial report of this project and has been published as 

Water-Supply Paper 1496-A, Chemistry of 

strontium in natural water (Horr, 1959).

A flame photometric procedure reported 

by Skougstad(1957) was modified slightly and 

adapted to the analysis of all water samples 

received as a part of the present investigation. The procedure utilizes a Beckman 

Model DU spectrophotometer with flame attachment, an oxygen-acetylene flame, and a 

photomultiplier tube attachment. A spectroscopic buffer solution added in equal amount 

to each sample and to standards minimizes 

effects of variations in amounts of interfering 

substances which may be present in the 

sample solutions.

Because the lower limit of detection of 

strontium by this procedure is, under optimum conditions, only 0.2 ppm, and because a 

significant number of the samples contained 

less than this amount, effort shave be en made 

to develop a routine laboratory method that 

can be used to determine strontium in water 

samples in concentrations at least as low as 

0.01 ppm. Two methods have been investigated. Work has been directed to the development of a procedure involving concentration of strontium in the sample by means of 

a cation-exchange resin prior to determination of strontium by flame photometry. The 

method has not yet been applied to regular 

analysis of samples, but seems to offer 

promise of providing a tenfold concentration 

of strontium which will give close to the desired sensitivity.

More recently, a spectrographic procedure, 

based on the copper-spark technique originally described by Fred and Nachtrieb (1947) 

and by Nachtrieb (1950) and employed also by 

Alexander, Nusbaum, and MacDonald (1954) 

for the determination of strontium in water, 

was developed and is now being used for all 

samples in which the values by flame photometric procedure are less than 0.2 ppm of 

strontium. In addition, samples containing 

0.2 to 1.0ppm of strontium are being checked 

by both procedures. The spectrographic 

method requires approximately 30 ml of water 

sample and is capable of detecting 0.005 ppm 

of strontium. The probable error of an analysis is about 10 percent of the amount 

present.

SAMPLING PROGRAM

Surface water samples from about 65 

points in the United States have been collected by the District Offices of the Water 

Resources Division of the U. S. Geological 

Survey. Nearly all points were regular sampling stations of the Geological Survey and 

were selected to represent, insofar as possible, the major streams and drainage areas of 

the country. At each point, three samples 

were obtained at intervals of several months 

to a year, to obtain water during high, low, or 

median flow conditions for the stream.

A comprehensive chemical analysis was 

made accordingto standard and accepted procedures by the district laboratory collecting 

the sample, and a portion of the sample was 

sent to the U. S. Geological laboratory in 

Denver for determination of strontium.

The streams sampled are listed in table 1, 

and the location of the sampling site for each 

stream is indicated in figure 1.

STRONTIUM CONTENT OF WATER

SURFACE WATER

Table 1 lists the strontium content of samples received and analyzed from May 1958 

through August 1959. All samples have been 

analyzed by the flame photometric procedure 

without prior concentration of the sample. 

Where strontium has also been determined 

spectrographically, the results for both procedures are given. Note that for a number 

of samples the results by the two independent
Table 1 Strontium content of surface water

No.

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

28 

29 

30 

31 

32

River

Allegheny ___________ ________

Arkansas __________________ _

do

Ame rican _ ___________________

Brazos

Brazos, Dbl. Mountain Fork ____ 

Brazos, Salt Fork __________ _

Broad _______________________

Canadian ____________________

Coeur d ' Alene ________________

Colorado ____________________

Columbia ____________________

___ do _______________

Cumberland __________________

Delaware ____________________

Embarrass __________________

Escambia__ __________ _ ____ _

Genessee ____________ _______

Gila __________________

Green _ _____________________

___ do ___ ___________

Guadalupe ___ ___________ _

Humboldt __ _ ________________

Jame s_____________________ 

Kansas ______________________

Kentucky _ _________________

Kern ________________________

Klamath _____________________

Lehigh ____________ ________

Maumee _______ __ _________ _

Mississippi __________________

Missouri _ _ ______ _ ________

Location

Kittanning, Pa________________

Little Rock, Ark ______ ____

Tulsa, Okla __ __________

Fair Oaks, Calif __________

Richmond, Tex _______________

Aspermont, Tex ______________

___ do___ _ _ _ ____

Boiling Springs, N. C _________

Logan, N. Mex _______________

Cataldo, Idaho________________

Cisco, Utah __________________

International Boundary ________

Rufus, Oregon________________

Williamsburg, Ky _______ ______

Morrisville, Pa ______________

Embarrass, Minn_____________

Century, Fla _ _______________

Rochester, N. Y ______________

Kelvin, Ariz ___ _ ____________

Green River, Utah ____________

Spottsville, Ky _________

Victoria, Tex ________________

Rve Patch NPV

Huron, South Dak _____ _ _ __ _

Topeka, Kansas ______________

Frankfort, Ky __ ______ ____

Bakersfield, Calif _ _ _________

Klamath, Calif _______________

Glendon, Pa________________ _

Waterville, Ohio______________

St. Francisville, La___________

Williston, N. Dak _________

Concentration o

Flame photometer

Flow stage

High

<0.2 

.4 

2.0

<.2

.8 

.8

.4

<.2 

<-2 

<.2

3.0 

.8 

<-2 

<.2 

.2 

<.2 

1.2 

<.2

<.2 

1.0 

.5 

.8

Median

<0.2 

.4 

1.0

2.2

.8 

.8

2.0

<.2 

<.2 

<.2 

.8 

.6

.6 

<.2

<.2 

.6 

.8 

.4

<.2 

1.0

Low

<0.2 

.4 

1.8 

1.4 

.4 

5.4 

9.8 

.8 

.8 

.4 

1.4 

<.2 

<.2 

.8 

<.2 

<.2 

.8 

.8 

2.8 

.6 

.8

<.2 

.4 

.8 

.8

1.4 

1.4 

<.2 

1.4

<.2 

.8
OCCURRENCE OF STRONTIUM IN NATURAL WATER

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STRONTIUM CONTENT OF WATER

methods do not give satisfactory agreement. 

The lack of agreement is attributed to the 

lack of sensitivity of the flame photometric 

procedure. When samples containing less 

than 1.0 ppm of strontium are analyzed, it is 

necessary to work in the extreme lower range 

of the calibration curve and also in the extreme lower range of the transmission-scale 

of the spectrophotometer. At this very low 

range, it is difficult to distinguish a reading 

difference of one scale division or less which 

corresponds to several tenths of a part per 

million strontium. The presence of interfering ions in the sample may also cause an 

error proportionally greater at strontium 

concentrations near the limit of sensitivity 

of the flame photometric method.

For these reasons, then, reported analyses 

of less than 1.0 ppm by the flame photometric 

procedure without preliminary concentration 

of the sample must be recognized as being 

subject to considerable error.

Where discrepancies exist, the samples 

are being rechecked by an ion-exchange concentration step prior to the flame photometric 

determination.

The streams selected for sampling have 

been classified on the basis of their strontium content. A stream at its sampling point 

is considered to be relatively low in strontium if it contains less than 0.50 ppm; relatively high if it contains more than 1.5 ppm; 

and moderate if it contains between 0.50 and 

1.50 ppm of strontium.

The geographical areas or regions where 

streams have been found to contain strontium 

at relatively low, moderate, or high levels of 

concentration are also shown in figure 1. 

Thus, the regions where the strontium content of surface waters is relatively low (less 

than 0.50 ppm) includes the Pacific Northwest, 

Northeastern United States, and the Central 

Lowlands, including the Lower Mississippi 

Basin and the western Gulf Coast area. Moderate amounts of strontium (0.50 to 1.5 ppm) 

are found in streams of Southeastern United 

States, most of the Great Plains Region, the 

Western Mountain and Plateau Regions, and 

California. Relatively high concentrations of 

strontium occur in the surface water of an 

area that includes northern and western Texas 

and southern New Mexico and Arizona.

The data so far obtained reveal three exceptions to this geographical distribution. 

The Maumee River at Waterville, Ohio, contains relatively more strontium than other 

streams sampled in this area. This is probably due to localized geologic conditions that 

supply considerable amounts of strontium to 

ground and surface waters of the area. It is 

known, for example, that there are extensive 

deposits of celestite in northern Ohio.

Two other streams do not fall within the 

above classification for the region in which 

they are located. Preliminary results show 

that the Humboldt River at Rye Patch, Nev., 

and the Rio Grande at San Ildefonso,N. Mex., 

contain somewhat less strontium than the 

other streams in those regions. This, again, 

is probably due to specific localized geologic 

conditions.

GROUND WATER

In addition to the surface water sampling 

program, about 150 samples of ground water 

have been analyzed for strontium. These 

samples represent ground water sources in 

California, Colorado, Iowa, Kansas, Maine, 

Minnesota, Mississippi, Montana, Nebraska, 

Nevada, New Mexico,North Dakota, Oklahoma, 

Oregon, Washington, West Virginia, Wisconsin, and Wyoming. Most of these samples 

were taken from public water supplies.

The strontium concentration of these samples ranged from less than 0.2 ppm to 36 

ppm. Samples from two wells in the known 

high-strontium area of East-central Wisconsin contained 24 and 36 ppm, respectively. 

Several well samples from Iowa contained 

from 2.0 to 3.0 ppm, and one well sample 

contained 8.8 ppm. One sample from Kansas 

contained 9.2 ppm; and certain samples from 

Colorado, Minnesota, Nevada, and North Dakota contained moderate amounts. A great 

proportion of the samples analyzed contained 

less than 0.50 ppm of strontium.

Although the strontium content of individual samples is not included here, table 2 lists 

the maximum strontium concentration found 

in any one sample from each State. The 

number of different sources sampled in each 

State is included in the table.
OCCURRENCE OF STRONTIUM IN NATURAL WATER

Table 2 Maximum concentration of strontium in 

ground waters sampled

State

California--.-

Colorado.----

Iowa_________

Kansas __....__

Maine _______

Minnesota-___

Mississippi _.

Montana _____

Nebraska ____

Nevada ______

New Mexico __

North Dakota _

Oklahoma

Oregon ______

Washington- __

West Virginia.

Wisconsin____

Maximum 

c one ent rat ion 

of strontium, 

(ppm)

0.2

1.6

1 8.8

9.2

.2

1.3

.1

.8

.8

1.8

.2

1.2

.2

.2

.2

2 116

36

Number 

of samples

7

15

6

2

2

8

2

4

9

17

9

2

2

19

10

1

2

1 2.4 to 3.0 ppm of strontium found in five 

samples. 

2 Oil well brine.

REFERENCES

Alexander, G. V., Nusbaum, R. E., and MacDonald, N. S., 1954, Strontium and calcium

in municipal water supplies: Am. Water 

Works Assoc. Jour., v. 46, no. 7, p. 643- 

654.

Blanchard, R. L., Leddicotte, G. W., and 

Moeller, D. W., 1958, Second United Nations Internatl. Conference on the Peaceful Uses of Atomic Energy, Geneva, Switzerland, Report A/Conf. 15/P/796, issued 

by U. S. Atomic Energy Comm. Tech. Inf. 

Service, Oak Ridge, Tenn.

Fred, M., Nachtrieb, N. H., and Tomkins, 

F. S., 1947, Optical Soc. America Jour., 

v. 37, no. 4, p. 279.

Horr, C. A., 1959, A survey of analytical 

methods for the determination of strontium in natural water: U. S. Geol. Survey 

Water-Supply Paper 1496-A, 18 p.

Nachtrieb, N. H., 1950, Principles and practice of spectrochemical analysis: New 

York, McGraw-Hill, 324 p.

Nichols, M. S., and McNall, D. R., 1957, 

Strontium content of Wisconsin municipal 

waters: Am. Water Works Assoc. Jour., 

v. 49, no. 11, p. 1493-1498.

Odum, H. T., 1951, Strontium in Florida 

waters: Florida Water Survey and Research Paper no. 6, November 30, 1951, 

p. 20-21.

Skougstad, M. W., 1957, Flame photometric 

determination of strontium in water: U. S. 

Geol. Survey open-file report, 18 p.

INT.DUP,,D,C.60- 68 671