ABSTRACT

Operation of nuclear facilities such as research reactor and it's supporting installation in Serpong Nuclear Area may release controlled radionuclides to Cisadane River and then it would flow to Jakarta Bay. There are limited marine radioecology studies or radionuclides monitoring at Jakarta Bay. Therefore monitoring of 239/240 Pu and 137 Cs was carried out from Tanjung Pasir to Tanjung Kerawang. The ERICA Assessment Tool was used to evaluate radiological risk in the marine environment of Jakarta Bay area. The 137 Cs concentration in sea water and sea sediments were in range of 0.17-1.17 Bq.m-3 and 0.34-1.21 Bq.kg-1 , respectively. Moreover, result of 239/240 Pu measurement showed that concentration at sea water and sea sediment were range from < MDA-0.53 mBq.m-3 and 2.64-55.70 mBq.kg-1 respectively. The results of risk analysis were indicated that all the total dose rates per organism were millions time lower than the screening rate (10 mGy.h-1).

The behavior of anthropogenic radionuclide 137 Cs in the water and sediment has been examined with regard to particle size, organic sediment, and other physical conditions in the Sayung estuarine waters of Demak. Previously, this estuary was used as shrimp culture brackish water ponds that were affected by serious erosion and intrusion. Furthermore, this regency rapidly industrialized over the last three decades. The activities of 137 Cs in the six stations in water and sediment were in the 0.0116-0.4509 mBq/L and 0.3747-1.2442 Bq/kg ranges with mean activities of 0.2278 mBq/L and 0.8594 Bq/kg, respectively, depending on the prevailing physicochemical regime at the sampling station. The highest activities of aqueous 137 Cs occurred in station 2 but the highest in sediment occurred in station 6 located closed to the main land of Sayung. Fast current effectively diluted 137 Cs as a conservative radionuclide in seawater, thus the activity of 137 Cs in seawater decreased when the current speed increased. This effect was caused in part by industrial pollutants that adsorbed 137 Cs and precipitated onto the surface sediment. Organic matters and clay materials in sediment were not significantly effective at binding 137 Cs in Sayung waters in the industrial coastal area, but the correlation increased in open areas separated by a breakwater (second group stations) and the location further from the beach or in open sea. This indicates that industrial pollutants are more effective at binding 137 Cs than organic matters and clay materials. Fine grain size sediment is also more ineffective at binding 137 Cs; it may be caused by the sediment's high total organic matter content.

The present status of marine radioecology condition at the coastal of Kalimantan was determined based on monitoring of the radionuclides concentration in marine compartment of West, South and East Kalimantan. The characteristicof Pacific Ocean contribute to the distribution of radionuclide in Kalimantan from the Indonesian Through Flow (ITF) that passes through the Makassar Strait. The aim of this research is to determine the concentration of radionuclides and regional oceanographic effects on the distribution of radionuclides in the coasts of Kalimantan. Gamma radionuclides activity concentration were measured using High Purity Spetrometer Gamma Detector (HPGe) that is integrated with Genie 2000 software analysis. Modelling processes and field observation from previous study become reflelction of Kalimantan regional sea characteristic. The result of this research shows that the baseline data that represented natural and antrophogenic radionuclides are comparable with other regions in Indonesia. The concentration of natural radionuclides in the sediments showed that there are no contamination of Naturally Occurring Radioactive Material (NORM) and 137Cs.