Present status of 137Cs in seawaters of the Lombok Strait and the Flores Sea at the Indonesia Through Flow (ITF) following the Fukushima accident

Due to thermocline and surface water from the western equatorial Pacific Ocean, which are transported to the
Indian Ocean, Indonesian marine waters play an important role in the global ocean circulation. The objective of
this study was to assess the spatial distribution of 137Cs in the Lombok Strait as part of a national monitoring
program concerning the possible impacts of radionuclides released as a result of the Fukushima accident.
Sampling was conducted in the Flores sea and Lombok Strait on 15 to 24 November 2013. Measurements for the
Lombok strait showed that 137Cs concentrations at surface layer, thermocline layer and 1000 m depth were
0.27 Bq m−3; 0.42 Bq m−3 and < MDA (0.01 Bq m−3
), respectively. The water concentration of 134Cs at all
monitoring stations were under MDA (0.01 Bq m−3
). The results the study indicate that the radiocesium input was from global fallout.