604 TRANSURANIC ELEMENTS IN THE ENVIRONMENT 



Hill and Hartwell reservoirs, located in the Piedmont region (Fig. 1). Each reservoir has a 

 capacity exceeding 3 km^ and can contain the equivalent of one-half to one year's flow 

 for the region of ttie river where it is located. 



The Savannah River estuary is relatively narrow (about 0.5 km) and is maintained at a 

 minimum depth of 11 m throughout its length of 35 km to accommodate shipping. To 

 maintain the depth of 1 1 m in the harbor requires practically continual dredging, and the 

 dredge materials are dumped on adjacent areas to the north of the harbor. The harbor 

 region has a tidal range of 2.1 to 2.4 m. The estuary classification is that of a moderately 

 stratified one. The estuary has been heavily polluted with raw sewage and industrial 

 waste, but these pollutants have been reduced considerably in the last few years. 



Sampling 



Water, sediment, and seafood samples from the Savannah River and its estuary were 

 collected and analyzed to permit transport, inventory, and dose-to-man calculations. The 

 location of the sampling station for plutonium transport in the Savannali River watershed 

 is shown in Fig. 1. This location was chosen because the sampler could be easily located 

 to take water samples near midstream. Montlily composite samples were collected. 

 Sample bias was avoided by taking four samples per day, about 300 cm^ each, from a 

 depth of 1 m with an automatic compositing sampler. 



Estuary water and sediment sampling locations are shown in Fig. 2. Sediment was 

 collected in marshes where vegetation lended stability to the sediments. The sediments 

 were collected by inserting a 3.6-cm-diameter core barrel into the sediments. The cores 

 were then extruded, sectioned, and bottled. Estuary water samples were 50-liter grab 

 samples from a depth of 1 m. 



Oysters and crab meat were obtained from a local wholesaler, who obtained the 

 oysters from Wassaw Island and the crabs from crab pots located in Wassaw Sound 

 (Fig. 2). Clams were collected from Port Royal Sound, which is about 32 km north of the 

 mouth of the Savannah River estuary. Shad were netted in the Savannah River, and 

 mullet and speckled trout were obtained from a local wholesaler whose boats work in the 

 Savannah River estuary and nearby waters. 



Analytical Methods 



The procedure developed by Wong, Brown, and Noshkin (1978) for concentrating 

 plutonium from large volumes of water was adapted for use on these water samples for 

 both plutonium and americium analyses. In the modified method the 50 liters of water in 

 the drum was adjusted to pH 2 with hydrochloric acid. Plutonium-236 and americium- 

 243 spikes were added, and the sample was equilibrated for 7 to 10 days. At the end of 

 the equilibrium period, 40 cn^^ of saturated potassium permanganate was added and the 

 pH was adjusted to 8 with sodium hydroxide. The potassium permanganate was reduced 

 by using a slight excess of sodium bisulfite. The hydrated manganese oxide was collected 

 on a \-iJim cotton filter by continually recirculating the sample through the filter at 

 12 liters/min for 25 min. Recirculation had the advantage of keeping the water vigorously 

 stirred as it was continually passed through the manganese oxide bed being collected on 

 the filter. The samples were ashed while wet to avoid rapid combustion. The plutonium 

 analyses were performed according to a procedure developed by Butler (1965) and 

 Sanders and Leidt (1961) or by the LFE Laboratories, Richmond, Calif. All americium 

 analyses were done by the LFE Laboratories. 



