6 
All water samples are analyzed unfiltered. To determine the salinity, a water sample is taken 
from each sampler. 
134 Cs and l37 C$ 
Caesium is coprecipitated with potassium hexanitrocobaltate from 50 - 500 1 of sea water, 
purified and finally precipitated as caesium iodobismuthate. The chemical yield is determined 
gravimetrically, the activity is measured in a Low-Level-Beta-Counter [16]. Before analysing 
samples of more than 200 1, l37 Cs is extracted from the sea water by passing a potassium 
hexacyanocobaltate-(II)-ferrate(II) adsorbend [2]. The adsorbend is then measured gamma-spec - 
troscopically to determine the 137 Cs activity or the 137 Cs/ l34 Cs activity ratio. 
!^Sr 
To determine "Sr, the activity of its decay product is isolated by fluid-fluid-extraction from 
up to 200 1 of water. Its oxide is then measured using a Low-Level-Anticoincidence-Beta- 
Counter [3]. To improve the method's detection limit in case of deep water samples, thorium- 
234 is first separated by Zr 3 (Po 4 ) 4 coprecipitation. 
Transuranics 
239+240 Pu, 238 Pu and 241 Am are extracted from 200 1 sea water samples after Murray and Statham. 
The samples are electroplated separately for Pu and Am and are measured alpha-spectroscopical- 
ly [12]. 242 Pu and 243 Am are used as yield tracers. 241 Pu is determined on the basis of the 421 Am 
activity ascent after a few years. 
Tritium 
After vacuum distillation, 325 ml water samples are enriched, with a yield of almost 80%, in 
electrolytic cells like those of Ôstlund [14], equipped with electrodes of stainless steel (anode) 
and phosphated iron (cathode) after Zutshi [18]. 5 ml of the concentrate is decomposed by man 
ganese in an autoclave. The resulting gas sample is measured in a Low-Level-Intemal-Gas 
Counter [11]. The limit of detection of this method is 0,01 Bq/1. 
Literatur 
[1] Borcherding, I. and H. Nies, 1986: 
An Improved Method of the Determination of ^Sr in Large Samples of Seawater. 
Journal of Radioanalytical and Nuclear Chemistry, Articles, Vol. 98, No. 1, 127-131 
[2] Eicke, H.-F., 1974: 
Eine Methode zur Anreicherung und Bestimmung sehr geringer Gehalte von l37 Cs im 
ozeanischen Tiefenwasser. Dt. hydrogr. Z., 27, 20-26 
[3] Fukai, R., G. Statham and K. Asari, 1976: 
A Rapid Method for ‘"Sr Analysis by HDEHP Solvent Extraction Application to Large 
Volume Water Samples. Rapp. Comm. int. Mer Médit., 23 (7), 149-150