384 TRANS URANIC ELEMENTS IN THE ENVIRONMENT 



communities were typical of those occurring on abandoned fields of similar soil types in 

 the southeastern United States. A 5-m-wide strip along the southwestern margin of each 

 field has been mowed regularly for several years. The soil in both fields is classified as 

 Vaucluse, a liighly leached Ultisol characterized by sandy A horizon and sandy clay B 

 horizon. Both fields were acidic with a similar pH (~4.6). 



The climate of the SRP area consists of mild winters and long, warm, humid summers. 

 Temperatures average about 9°C in the winter and 30°C in the summer. The average 

 annual temperature is 18°C. The average annual relative humidity and rainfall are 70% 

 and 120 cm, respectively. The maximum annual precipitation recorded was 187 cm in 

 1929, and the minimum was 71 cm in 1933 (Langley and Marter, 1973). 



White Oak Creek Floodplain, Oak Ridge 



Manhattan Project operations in 1944 produced treated wastes containing plutonium, 

 americium, and curium. Following soda-ash treatment to precipitate various ions, the 

 liquid effluents were released to White Oak Creek (WOC). Trace quantities of ^^^Pu, 

 "^^^Pu, ^^' Am, and ■^'*'*Cm were deposited along the water course, in an intermediate 

 retention pond, and, finally, in White Oak Lake. These elements were deposited in 

 sediments of a retention pond over a 6-month period in 1944. No additional radioactivity 

 is believed to have been deposited at this location since the pond was drained in late 

 1944. The former retention-pond site currently constitutes the first floodplain terrace of 

 WOC. 



The alluvial soil of the floodplain is representative of bottomlands of the Tennessee 

 Valley and Ridge province. Azonal characteristics predominate because of concurrent 

 erosion and deposition of materials during periodic floods. The soil profile remains 

 relatively undeveloped, although the accumulation of humus is evident from a 

 dark-brown coloration in the 0- to 3-cm zone. 



Sedimentation during the 6-month impoundment in the temporary holding basin 30 

 yr ago contributed new sedimentary materials. A Tennessee Valley Authority (1975) 

 survey in 1951 reported that approximately 2100 m"^ of sediment had been deposited at 

 this locality. This volume, distributed uniformly over the research site, represented an 

 increment of approximately 9 cm of new sediment. However, equal deposition was 

 unlikely, and the exact history of sedimentation associated with the 1944 impoundment 

 is unknown. 



Textural analyses indicate that soils are silty loam (72% silt and 24% clay) and 

 contain almost no sand or gravel (Tamura, 1976). Although this texture is representative 

 of the floodplain, isolated gravel lenses occur irregularly across the floodplain and within 

 the soil profile. 



The soil reaction is mildly alkaline since pH ranges from 7.1 to 7.6. The mild 

 alkalinity is probably caused by the soda-ash method of waste treatment used before 

 effluents were released from laboratory operations. Data have not been obtained on base 

 exchange or soil fertility, althougli, on the basis of plant growth and crop performance, 

 the site possesses high fertility potential. 



The climate at Oak Ridge, Tenn., is characterized by mild winters and warm, humid 

 summers. Average temperatures of the continental climate are 24°C in summer and 



