Strontium concentration ocean

The distribution coefficients determined for strontium (at U c) and for barium (at ll C for 3 0 < -log < U.5 and at for all other values of -log Ci) are summarized in Figure 2. Due to the relatively high concentration of strontium in seawater (and hence the relatively high concentration initially in the clay-phase) only limited data for strontium were obtained. The distribution coefficients which were obtained appear to behave similarly to the respective coefficients for barium but are somewhat smaller in magnitude. For solution-phase concentrations on the order of 10"3 mg-atom/ml, the barium coefficients appear to be between 10 and 100 ml/gm, and for solution-phase concentrations on the order of 10 ", the barium coefficients appear to be on the order of 10, as was expected. Furthermore, the coefficients for both strontium and barium are generally consistent with the corresponding data obtained for similar oceanic sediments and related clay minerals found within the continental United States (6,758 13) The... 

For the nuclides studied (rubidium, cesium, strontium, bariun silver, cadmium, cerium, promethium, europium, and gadolinium) the distribution coefficients generally vary from about 10 ml/gm at solution-phase concentrations on the order of 10 mg-atom/ml to 10 and greater at concentrations on the order of 10 and less. These results are encouraging with regard to the sediment being able to provide a barrier to migration of nuclides away from a waste form and also appear to be reasonably consistent with related data for similar oceanic sediments and related clay minerals found within the continental United States. 

Asia. Large rivers of Asia are clearly the less well documented in terms of trace-element concentrations. This is mainly due to their low abundances of trace elements, probably related to their high pH character. A couple of studies have focused on the riverine input of metals to the Arctic and Pacihc oceans. Himalayan rivers have not been documented for REEs (except the Indus river), but have been analyzed for particular elements such as strontium, uranium, osmium, and radium. There is clearly a need for data on trace elements in the rivers of Asia, particularly in the highly turbid peri-Himalayan rivers. 

In modern oceans the concentration of strontium is —8 ppm and its residence time is —4-8 Myr... 

Strontium is widely distributed in the earth s crust and oceans. Strontium is released into the atmosphere primarily as a result of natural sources, such as entrainment of dust particles and resuspension of soil. Radioactive strontium is released into the environment as a direct result of anthropogenic activities. Stable strontium can be neither created nor destroyed. However, strontium compounds may transform into other chemical compounds. Radioactive strontium is formed by nuclear reactions. Radioactive decay is the only mechanism for decreasing the concentration of radiostrontium. The half-life of 90Sr is 29 years. 

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 present authors have recently described (I, 2) the development of an accurate and precise analytical method using ion-exchange concentration and flame photometry to measure the strontium and barium concentration of sea water from the same sample. Initial analyses indicated that there is possibly a small, but significant, variation in the strontium/ chlorinity ratio with respect to depth (2, 3). The results of the analyses for barium indicated that, as expected, the variation in the barium/ chlorinity ratio is much larger. This communication reports the results of the analyses of samples from several ocean stations for strontium and barium. 

Radioactive wastes come directly from nuclear-reactor-fuel reprocessing plants and from industries employing radioactivity for processing work. The dominating elements from nuclear reactor fuels are cesium 137 and strontium 90, with the latter th,e controlling isotope owing to low permissible concentration values (Table 10-2). Rodger cites an example to illustrate the severity of the problem. In the year a.d. 2000 the installed reactor capacity on a world-wide basis is predicted to be 2.2 X 10 Mw. If this system is operated for 50 years, the Sr steady-state level (rate of production = rate of decay) would be 8.6 X 10 curies, which would require 5 per cent of the entire world ocean volume to dilute to the maxi-... 

In ocean water, strontium is the most abundant trace element at an average concentration of 8.1 ppm [8]. In natural water sources, such as rivers, springs, and wells, concentrations from 0.002 to 0.375 ppm, with an average of 0.06 ppm, were demonstrated [9,10]. In municipal water supplies in the United States, values were found to range between 0.002 and 1.2 ppm (median value = 0.11 ppm), depending on the source and hardness of the water. For hard waters of Texas the concentration even exceeded 1.2 ppm [10]. In air, strontium is normally not measured, since it is a natural pollutant from dust. 

Only 11 elements can be considered major components of seasalt the cations sodium, potassium, magnesium, calcium and strontium, and the anions chloride, sulphate, bromide, hydrogen carbonate (carbonate), borate (borid acid) and fluoride. These major dissolved constituents (concentrations > 1 mg/kg in ocean waters) make up > 99 % of the soluble ionic species of seawater. The elemental ratios are relatively constant throughout the world ocean, and their concentrations change due to the addition or substruction of water only (concept of conservatism ). Therefore, it is possible to characterize the composition by determining only one constituent that is easy to measure and is conservative in its behaviour. An example is chlorinity (Cl, as defined in Section 11.2.4). 

The relative standard deviation for measurements of the total alkaline earths in ocean waters is reported to be less than 0.1 % (Pate and Robinson, 1961 Culkin and Cox, 1966). In the case where an automatic titration system is applied, the author found a comparable coefficient of variation (c.v.) of 0.15 %. However, for water of lower salinity with an average magnesium content of 0.205 g/kg, a c.v. of only 0.65 % was measured by the author. Although the determination of the magnesium concentration is based on the difference between titrations, errors caused by the measurements of calcium and strontium can be neglected, when the analytical procedure described in Section 11.2.1 is used. 

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