High-resolution historical records from Pettaquamscutt River basin sediments: 1. Pb-210 and varve chronologies validate record of Cs-137 released by the Chernobyl accident

摘要

Cesium-137 derived from the explosion of the Chernobyl reactor in 1986 was preserved in anoxic sediments from a coastal environment in southern Rhode Island. Although the radioactive plume was detected in surface air samples at several locations in the United States, this is the first known record of a Chernobyl Cs-137 peak in sediments from North America. The inventory of Chernobyl Cs-137 that was preserved in the Pettaquamscutt River is small compared to European counterparts and should only be detectable for the next 15-20 yr. However, the presence of two Cs-137 peaks (1963 and 1987) identifies a well-dated segment of the sediment column that could be exploited in understanding the decomposition and preservation of terrestrial and aquatic organic matter. Different methods for calculating the Pb-210 chronology were also evaluated in this study and checked against independent varve counting. The end result is a detailed chronology of a site well suited for reconstruction of historical records of environmental change. Copyright (c) 2005 Elsevier Ltd.