The Distribution of Mercury, Cesium‐137, and Plutonium in an Intermittent Stream at Los Alamos

Abstract

AbstractThis paper summarizes the results of a study on the distribution of Hg, 137CS, 238Pu, and 239,240Pu in channel sediments and adjacent bank soils in an intermittent stream used for treated liquid effluent disposal since 1963.Concentrations of the three radionuclides and Hg in stream bank soils were comparable to adjacent channel sediments demonstrating that the stream bank serves as a deposition site for chemicals released to the channel. This finding has important implications on the long‐term behavior of effluent contaminants since other studies at Los Alamos have shown that the vegetated stream banks retard downstream movement of chemicals bound to soils and provide a pathway for transport of these materials to biota.Concentrations of the radionuclides and mercury were more uniformly distributed with distance and depth in the channel sediments than in the bank soils. The action of periodic surface water in the channel partially explains those differences. Statistical analysis of the data revealed that 50 to 85% of the variability in contaminant concentrations in bank and channel locations was due to variation with distance while depth contributed relatively little to variability.