Contrasting cesium dynamics in neighboring deep and shallow warm-water reservoirs.
To measure the long term retention and seasonal dynamics of an initial 4 kg addition of (133)Cs into an 11.4-ha, 157,000 m(3) reservoir (Pond 4, near Aiken, South Carolina, USA), the concentrations and inventories of (133)Cs 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 (133)Cs 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 (137)Cs 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.
Pinder
John E
JE
Department of Biology, Texas Christian University, Ft. Worth, TX 76129, USA.
Hinton
T G
TG
Whicker
F W
FW
D002586:Cesium / Q000032:analysis / Q000737:chemistry*; D002588:Cesium Radioisotopes / Q000032:analysis / Q000737:chemistry; D004784:Environmental Monitoring; D005618:Fresh Water / Q000737:chemistry*; D007501:Iron / Q000032:analysis; D007700:Kinetics; D008345:Manganese / Q000032:analysis; D011188:Potassium / Q000032:analysis; D012621:Seasons; D012964:Sodium / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
D002588:Cesium Radioisotopes; D014874:Water Pollutants, Chemical; D002586:Cesium; D008345:Manganese; D012964:Sodium; D007501:Iron; D011188:Potassium