Strontium in sea water

Armstrong R. L. (1971) Glacial erosion and the variable isotopic composition of strontium in sea water. Nature Phys. Set 230(14), 132-133. 

Peterman Z. E., Hedge C. E., and Tourtelot H. A. (1970) Isotopic composition of strontium in sea water throughout Phanerozoic time. Geochim. Cosmochim. Acta 34(1), 105-108. 

Spreadsheet Summary In Chapter 4 of Applications of Microsoft Excel in Analytical Chemistiy, a multiple standard additions procedure is illustrated. The determination of strontium in sea water with inductively coupled plasma atomic emission spectrometry is used as an example. The worksheet is prepared, and the standard additions plot is made. The unknown Sr concentration and its standard deviation are obtained. 

The strontium and barium analyses of sea water are reported. Concentrations of these elements in sea water were simultaneously determined by a combination of ion exchange concentration and flame photometry to ascertain more precisely strontium/chlorinity and barium/chlorinity ratios and to investigate the magnitude and nature of the strontium/chlorinity ratio variation if it was found. The results of the analyses of several ocean stations presented indicate that there is a small (ca. 3%) but statistically significant variation in the strontium/chlorinity ratio with respect to depth in sea water. An indication of a possible variation in the absolute amounts of strontium in sea water with the geographical location has also been observed. The barium/chlorinity ratio variation with respect to depth was found to be much larger (ca. 90%) than that of strontium. 

The alkali metals of Group I are found chiefly as the chlorides (in the earth s crust and in sea water), and also as sulphates and carbonates. Lithium occurs as the aluminatesilicate minerals, spodimene and lepidolite. Of the Group II metals (beryllium to barium) beryllium, the rarest, occurs as the aluminatesilicate, beryl-magnesium is found as the carbonate and (with calcium) as the double carbonate dolomite-, calcium, strontium and barium all occur as carbonates, calcium carbonate being very plentiful as limestone. 

Strontium is found in small quantities in many rocks and soils, mostly associated with calcium and barium. Its abundance in the earth s crust is about 370 mg/kg, about the same as barium. The average concentration of this metal in sea water is about 7.9 mg/L. 

Infomation as to the fate of strontium in the animal and plant organism is of particular interest at the present time. Harrison and Raymond (33) developed a rapid method for determining the metabolism of strontium and barium without interference from calcium. After short irradiation in BEPO, samples were chemically treated and the isotopes were gamma counted using a scintillation counter. More recently strontium and barium have been determined in bone by Sowden and Stitch (95). Strontium at the 5-60 ppm level has been determined in animal tissue by Brooksbank, et al. (10) while Bowen (5) has determined strontium and barium in sea water and marine organisms. 

The five metal ions Na, Mg2+, Ca2+, K+, and Sr2 + which occur at concentrations down to 1 mg/1 belong to the major constituents, since they contribute significantly to the salinity. Sodium, magnesium, and potassium are found in sea water in nearly constant proportions2) whereas calcium shows statistically a higher concentration in deeper waters than in surface waters by about 0.5 %. In the case of strontium the mean Sr Cl ratio seems to be lower in the surface layers by up to 3 % 4). 

Although strontium is one of the major metal ion constituents in sea water, its concentration of 8.1 mg/1 is about 50 times lower than that of calcium. No procedures are known for a commercial recovery of strontium from sea water. Strontium can be extracted from sea water along with uranium and other elements by hydrous titanium oxide. However, only 120-fold concentration has been reached... 

Sea water is a very complicated solution of many substances. The main dissolved component of sea water is sodium chloride, common salt. Besides sodium and chlorine, the main elements in sea water are magnesium, sulfur, calcium, potassium, bromine, carbon, nitrogen, and strontium. Together these 10 elements make up more than 99% of the dissolved materials in the oceans. In addition to sodium chloride, they combine to form such compounds as magnesium chloride, potassium sulfate, and calcium carbonate (lime). Animals absorb the latter from the sea and build it into bones and shells. 

Complexones such as EDTA (complexone III) [1-3] and DCTA (complexone IV) [4,5] are suitable eluents, but other complexing agents, such as citrate [3,6] and sulphate [7] are also applied. Barium has been separated from strontium and other metals by cation-exchange chromatography using mixed HCl-organic solvent eluents [8]. Strontium has been enriched and determined in sea water [5] and in milk [2]. 

Jones et al. (1967) first reported that the average 8 Sj./86Sr ratio of 15 water samples from a depth profile of Lake Vanda is 0.7149 0.0(X)1 which is identical within analytical error to the Sr/ Sr ratio of 0.7146 0.0002 of strontium in the water of the Onyx River. On the other hand, the Sr/ Sr ratios of strontium in Lake Vanda and the Onyx River differ markedly from the average Sr/ Sr ratio of the Cenozoic basalt of the McMurdo Volcanics (0.7043) and from the average Sr/ Sr ratio of two samples of seawater from the Ross Sea (0.7094). These results indicate unequivocally that the strontium at all levels in Lake Vanda and in Onyx River did not originate from marine sources or by weathering of Cenozoic basalt or volcanic ash in Wright Valley. 

Strontiam.—Sr, a.n. 38 a.w. 87-63. Fox and Ramage were the first to show that strontium is generally distributed in marine animals, and their work has been confirmed by Webb. Strontium is the fifth most abimdant metal in sea water, the concentration being about 13-5 mg. per litre. 

The concentration of strontium in a sea water aquarium is determined by atomic absorption using the method of... 

De Kersabiec et al. [708] have described a Zeeman method for the determination of copper, lead, cadmium, cobalt, nickel, and strontium in brines and in the soil water adjacent to the Red Sea. 

The accuracy of the activation analysis method when applied to sea water has been checked by comparison with other methods in the case of rubidium and strontium. The rubidium content (Table VI) of a sample of... 

Strontium determinations in soils, sea water, etc., have the same topicality as similar determinations in biological materials. The strontium and barium content of a number of soils and plants has been determined by Bowen and Dymond (5). They found that strontium was preferentially absorbed with respect to calcium by plants from most of the )ils considered while barium was taken up much less readily. 

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