Determination of natural and anthropogenic ¹²⁹I in marine sediments

Abstract

129 I concentrations in two sediment cores from the continental slope near Cape Hatteras were determined with tandem accelerator mass spectrometry (TAMS). The natural 129 I/ 127 I ratios in these cores are approximately 10 −12 . The input of anthropogenic 129 I has increased this ratio to values close to 10 −10 at the surface of the sediments. The observed natural level of 129 I is about two orders of magnitude above the current detection limit with TAMS, which opens up the possibility for applications of 129 I in the marine system such as dating of sediments and crude oils and tracing of slow water movement in sediments.