562 TRANSURANIC ELEMENTS IN THE ENVIRONMENT 



those found at Atolls that have not been contaminated by fallout (Noshkin, Eagle, and 

 Wong, 1976). 



Physicochemical States of ^^^^^"^^Pu and ^^^Pu 



In a model of the marine environment that can be used to predict effects, the water is the 

 central component; the water receives the inputs of metals and provides the transport 

 medium for uptake into the biosphere or loss to the sediments. Because of this central 

 role, the behavior and physicochemical states of the transuranic elements in seawater 

 must be known if a useful model of the system is to be constructed. Once the speciation 

 and behavior of these elements are known, their relative hazards can be predicted. Higli 

 concentrations of salts in seawater interfere with the methods used to measure the 

 physicochemical states and must be removed before the analysis for the transuranic 

 elements. Consequently separation and preconcentration from the saltwater matrix are 

 required at some stage of the analysis. Ideally the best method would be direct in situ 

 measurement of the elements in the field. Unfortunately, with present technology direct 

 field measurement is not feasible. The next best thing is to extract and concentrate the 

 elements in the field. This would eliminate some of the problems resulting from 

 contamination, losses during transport and storage of samples, and changes in chemical 

 speciation on storage in containers. 



The Battelle large volume water sampler (BLVWS) is a sampling system that can be 

 used to concentrate low levels of trace metals or radionuclides from natural waters in the 

 field (Silker, Perkins, and Rieck, 1971). This method effectively eliminates the need for 

 preservation and storage of water samples, extraction in the field, and evaporation or ion 

 exchange in the laboratory to concentrate the elements to a level sufficient for analysis. 

 The advantage of the BLVWS technique over the "conventional" techniques is that both 

 the total concentration and the physicochemical-state concentrations of the particulate 

 and soluble fractions can be measured. Collection efficiencies of the soluble fraction are 

 determined individually for each element during collection. In addition, much larger 

 volumes of water permit lower concentrations to be measured. 



An evaluation of a new sampling and measurement technique for transuranic elements 

 requires detailed studies of the precision and accuracy of the technique in both controlled 

 and natural environments. It also requires simultaneous measurements of samples that 

 have been collected by the more conventional methods. For the past several years, we 

 have attempted to set up experiments that would test the validity of the BLVWS 

 technique for plutonium measurements in both laboratory and field studies (Huntamer, 

 1976;Nevissi and Schell, 1975;Schell, Nevissi, and Huntamer, 1978). 



Description of the Sampler. The BLVWS is a field collector that can process as much as 

 4000 liters of water in 3 hr with the large sampler (28-cm diameter) and about 800 liters 

 of water with the small sampler (13-cm diameter), depending on the particulate loading. 

 The filtering section of the BLVWS normally consists of eight filters arranged in parallel. 

 The number of filters used can be expanded or reduced by removing or adding plates to 

 the BLVWS. The water, after passing through one of the filters, is then channeled througli 

 the sorption beds. The sorption beds generally consist of two to four 0.6-cm-thick 

 sections (Fig. 14). The use of individual sorption beds rather than one thick bed permits 

 the calculation of the collection efficiency for individual elements and permits easy 

 variation of the sorption-bed thickness. It also allows for the use of a mixture of different 

 sorption beds if desired. 



