Plutonium and cesium radionuclides in the Hudson River Estuary. Annual technical progress report, December 1, 1974--November 30, 1975

Abstract

We have obtained a large set of gravity cores from the Hudson Estuary through much of the ambient salinity range. A number of core sections have been analyzed for $sup 137$Cs, $sup 134$Cs, $sup 60$Co, and $sup 40$K by direct gamma counting, and for $sup 239$,$sup 240$Pu by alpha-spectrometry. The distribution of both $sup 137$Cs and $sup 239$,$sup 240$Pu indicates rapid accumulation in marginal cove areas and in the harbor region adjacent to New York City. The distribution of both $sup 137$Cs and $sup 239$,$sup 240$Pu in the sediments is quite similar in surface sediments, and the trends with depth in cores are also similar. The ratio of sediment $sup 239$,$sup 240$Pu to $sup 137$Cs throughout the sampled salinity range (0-20 $sup 0$/$sub 00$) approximates that in fallout, except near the nuclear reactor at Indian Point where releases of $sup 137$Cs result in a ratio lower (0.004 to 0.008) than typical of fallout (0.015). Measurement amounts of reactor-derived $sup 134$Cs, $sup 60$Co, and $sup 54$Mn are found in nearly all of the samples containing appreciable $sup 137$Cs. These samples were between 15 km upstream of Indian Point reactor site and the downstream extent of our sampling, 70 km south of the reactor. (auth)