PLUTONIUM IN ROCKY FLATS FRESHWATER SYSTEMS 645 



BOULDER 

 (POP., 66,780) 



BROOMFIELD 

 (POP., 7282) 



/" 



r 



DENVER METROPOLITAN 

 AREA (POP., 711,295) 



Fig. 1 Rocky Flats installation relative to nearby population centers. 



organisms frequently exceeds concentrations in surrounding waters by orders of 

 magnitude. This concentration process may pose unexpected hazards when considering 

 food-chain transport. 



Before this investigation little information concerning plutonium movement in 

 aquatic systems was available (Stannard, 1973; Noshkin, 1972). Fallout and marine 

 studies comprised the bulk of this environmental data, with average concentrations in the 

 femtocurie range (Pillai, Smith, and Folsom, 1964; Aarkrog, 1971; Noshkin et al., 1971). 

 In general, all freshwater Siudies have concurred that sediments appear to be the major 

 reservoir for ultimate plutonium deposition and that relatively insignificant transport of 

 plutonium through biotic systems to man exists (Emery and Klopfer, 1976; Hakonson, 

 Nyham, and Purtymun, 1976). 



The purpose of tliis investigation was to determine the behavior of plutonium in 

 freshwater systems at the Rocky Flats Dow Chemical plutonium fabrication plant, 

 Golden, Colo. The objectives were to (1) investigate the distribution patterns of 

 plutonium in the biotic and abiotic components of the Rocky Flats freshwater systems, 

 (2) determine any concentrating processes that were occurring, and (3) determine if any 

 biological mobilization processes existed. It was the first attempt of its kind at delineating 

 the cycling processes of plutonium using a holistic systems approach. 



Methods and Materials 



Figure 1 shows the location of the Rocky Flats area relative to the larger surrounding 

 metropolitan areas. The plant site itself covers approximately 10 km-^ . 



Figure 2 shows the general sampling area at Rocky Flats. The principal study area 

 included the four holding ponds (B-series ponds) for waste solutions generated at the 

 plant complex. These ponds were drained by Walnut Creek, which flowed into Great 

 Western reservoir, the City of Broomfield's municipal water supply. Great Western's water 

 sources were provided by Walnut Creek (2%), Coal Creek (8%), and Clear Creek 

 watershed (90%) (Hammond, 1971). The A-series and C| ponds were monitoring ponds 

 that did not receive routine releases of plutonium waste. Pond Ai had received low-level 



