SREL Reprint #3145
Contrasting cesium dynamics in neighboring deep and shallow warm-water reservoirs
John E. Pinder III1, T.G. Hinton2, F.W. Whicker3
Abstract: To measure the long term retention and seasonal dynamics of an initial 4 kg addition of 133Cs into an 11.4-ha, 157,000 m3 reservoir (Pond 4, near Aiken, South Carolina, USA), the concentrations and inventories of 133Cs in the water column were measured at periodical intervals for 522 days following the 1 August, 1999 release. After rapid declines in concentrations and inventories during the first 90 days, the 133Cs concentrations in the water column declined at an average proportional rate of 0.004 d-1. However, there were periods of less rapid and more rapid rates of declines, and these were correlated with periods of increasing and decreasing K concentrations in the water column. The decline rates were less and the K concentrations greater in the winter than in the summer. In the deeper, neighboring monomictic reservoirs of Par Pond and Pond B, a yearly cycle of increasing and decreasing 137Cs concentrations in the water column is driven by anoxic remobilization of Cs from the sediments into a persistent summer hypolimnion. In Pond 4, whose mean depth of 1.6 m is too shallow to support a persistent anoxic hypolimnion, the pattern of yearly dynamics for K and Cs appear to be related to the accumulation and release of these elements from the extensive, seasonal macrophyte communities. The contrasting results between Pond 4 and Pond B suggest that a full appreciation of the relative importance of 1) anoxic remobilization and 2) accumulation and release by macrophytes in these systems remains to be established.
Keywords: 137Cs, 133Cs, Reservoir, Water column, Sediments, Macrophytes, Remobilization, Typha latifolia, Nymphaea odorata
SREL Reprint #3145
Pinder III, J. E., T. G. Hinton, and F. W. Whicker. 2010. Contrasting cesium dynamics in neighboring deep and shallow warm-water reservoirs. Journal of Environmental Radioactivity 101(2010): 659-669.