Chapter 6 



Precipitation on the Ocean Bottom 



65 



physical state of each if dispersed in sea water. 

 The estimates of physical states have been ob- 

 tained from oceanographic studies following 

 bomb tests and from considerations of the 

 "solution chemistry" of the elements. It should 

 be emphasized that the terms "solid" and "solu- 

 tion" are relative terms. Measurements made 

 during oceanographic studies invariably base 

 the division upon filterability. Such a division 



TABLE 5 An Estimate of Solid and Soluble 



Fractions for Fission Products in 



Sea Water 



TABLE 6 Geochemical Balance of Some 



Elements in Sea Water (from Gold- 



SCHMIDT, Quoted in Rankama and 



Sahama, 1950, Table 16.19) 



Element 

 Sr^« 



Sr^o +Y°° 

 Zr"" 



Cs^' -f Ba^ 

 Pm"^ 



Per cent of total 



activity at end of Physical state in 

 one year sea water 



3.8 Solution 



1.7-1- 1.7 Solution -f solid 



7.2 Solid 



15 Solid 



2.5 -j- 2.5 Mostly in solution 



1.5 -f- 1.5 

 26 -f26 

 5.6 



Solution 



Solid 



Solid 



obviously will place soluble elements that are 

 utlized by organisms in the solid or solution -{- 

 solid category. The settling characteristics of 

 elements so combined will depend upon prop- 

 erties of the organisms. To what extent anoma- 

 lies of this kind are in the estimate above can- 

 not be stated. However, the estimates agree 

 qualitatively with those made from knowledge 

 of the behavior of elements in systems where 

 biological activity is not a major variable. 



Culler (1954a), has noted that low level ac- 

 tivities discharged to White Oak Creek end up 

 primarily with the clay in a retention basin. 

 The character of the waste was not noted. 

 Krumholz (1954), however, found considera- 

 ble uptake of radioactivity in the biota with 

 subsequent relocation and dispersion in the 

 same region. 



Geochemical data 



An estimate of the behavior of several sea 

 water constituents can be obtained from the re- 

 sults of geochemical studies. These studies per- 

 mit an evaluation of the fraction of an element 

 supplied to the oceans that is removed from so- 

 lution. The removal processes may include one 

 or more of those previously mentioned. The 

 results permit no choice of mechanisms. Table 6 

 lists several elements found in sea water, the 



Total 

 supplied 



Element (ppm) 



Na 16,980 



K 15,540 



Kb 186 



Ca 21,780 



Sr 180 



Ba 150 



Fe 30,000 



Y 16.9 



La 11 



Ce 27.7 



Amount 

 present in 



ocean Transfer 



(ppm) percentage 



10,560 62 



380 2.4 



0.2 0.1 



400 1.8 



13 7.2 



0.05 0.03 



0.02 0.00007 



0.0003 0.002 



0.0003 0.003 



0.0004 0.001 



quantities supplied to and present in the oceans 

 and a quantity, the transfer percentage, which 

 is the percentage of "present" to "supplied." 



Large values of transfer percentage indicate 

 that relatively large fractions of the elements 

 supplied to the oceans stay in solution — small 

 values of transfer percentage that relatively 

 much is removed. 



Using the transfer percentages listed for 

 cesium, strontium, and cerium, and estimates of 

 the specific activities that would occur in the 

 oceans as a result of 10^^ megawatt hours nu- 

 clear power production, the reduction through 

 geochemical processes has been calculated. The 

 figures are given in Table 7. 



TABLE 7 Activity Reduction By Geochemical 

 Processes 



Specific 



Specific Transfer activity 



activity percent- after 



(c/gm) age removal 



Element (no removal) (c/gm) 



Cesium 8.6 X 10"^ 0.005 4.3 X 10"^ 



Strontium 6.8 X 10"' 7.2 4.9 X IQ-'" 



Cerium 1.8 X 10"^ 0.001 1.8 X lO"'" 



Laboratory data 



Floccing, possible in the disposal of wastes 

 rich in iron or aluminum, may assist in removal 

 of fission products. Unless settling times of nat- 

 ural or artificial floes are short, resolution and 

 biological uptake may reduce the settling factor 

 markedly. 



Goldberg (1954) has described the copre- 

 cipitation processes with iron and manganese. 

 While none of the fission product elements are 

 treated, analyses show that the amounts of trace 



