Pu AND Am IN SAVANNAH RIVER MARINE ENVIRONMENT 607 



The calculated rate of plutonium removal from the Savannali River watershed is 

 about 10% of that from the Great Miami River. On the basis of the 3-month average 

 plutonium concentration and measured flow rates (see Table 1 ), the estimated plutonium 

 transport in the Savannali River at Highway 301 is 0.22 mCi/month, or 2.6 mCi/yr. The 

 area of the Savannah River watershed above Higliway 301 is 81% of the total watershed. 

 So the amount of plutonium in the watershed above the sampling point is 0.81 x 55 Ci 

 from nuclear weapons fallout plus 4 Ci released by the SRP, or a total of 48.6 Ci. Thus 

 the annual removal rate is approximately 0.005%. The value reported for the 1400-km^ 

 watershed of tlie Great Miami River is 0.05% (Sprugel and Bartelt, 1978). 



TABLE 1 Plutonium Transport in the Savannah River 



*Mean ± standard error. 



Information concerning the transport and fate of americium in rivers and estuaries is 

 limited. The concentration of ^''^ Am in Savannah River water has not been accurately 

 determined; a few samples collected at Highway 301 indicate that it is about 

 0.05 fCi/liter, as compared with 2 3 9,2 4 op^ concentration of 0.25 fCi/liter. The ^"^^ Am 

 concentration is the same as that in the Mediterranean Sea (Fukai, Bullestra, and Holm, 

 1976) and Lake Michigan (Wahlgren et al., 1976) water, where ^"^^ Am concentration is 

 3 to 5% of the 2 3 9,240p^ concentration. If the same percentage existed in Savannah 

 River water, the concentration of ^"^ ' Am would be only about 0.01 fCi/liter. 



Savannah River Estuary 



The plutonium concentrations in tlie Savannah River estuary are not much different from 

 those in other estuaries in the southeastern United States; in fact, the concentrations in 

 this estuary are lower than those in some others. Water concentrations of ^^''^"^"Pu were 

 determined in the Neuse and Newport river estuaries of North Carolina for comparison 

 v^dth concentrations in the Savannali River estuary. The results (Fig. 3) show that the 

 concentrations in the Newport River estuary are about three times as great as those in the 

 Neuse River or Savannali River estuaries, which are about equal. 



The three estuaries and the rivers supplying them are quite different. The Neuse and 

 Savannah rivers flow through both the Piedmont plateau and Atlantic Coastal Plains. 

 Only the Savannah River has its flow regulated by reservoirs. The volume of flow in the 

 Savannah River is about twice that of the Neuse River and 10 times that of the Newport 

 River. The Newport River estuary is extremely small and shallow witli depths of less than 

 1 m at mean low water as compared with at least 4 m in the other two. Suspended soHd 

 (5-/im fraction) concentrations in the Newport River estuary are about one and one-half 



