Groundwater Drainage and Soil Formation Effect on High Natural Radiation Exposure in Biak, Papua

Unusual phenomenon of radium accumulation in soil is take place in Biak Island. Preliminary field survey delineates the area around Maryendi, Darmapis and Denafi which indicates the high radiation dose from 50 to 4,032 nSv/h. Further observation and measurement of soil profile yield conclusion of high radiation only consists in top most
part of soil in the thickness range of tens centimeter. Bedrock of soil is limestone, no potential source of uranium and thorium surrounding the area such as intrusive or volcanic rocks. To gather scientific reason of this phenomenon, several
research methods applied consisted of satellite imagery analysis, chemical analysis, and scanning electron microprobe
(SEM) of the soil sample. Based on satellite imagery analysis, geomorphology and groundwater drainage plays significant role in transport and precipitation process of radium from limestone to soil. Results of chemical analysis and SEM conclude that soil chemical properties allows the deposition of radium in the soil. This research is very valuable for further study or exploration of radioactive elements in the type of surficial deposits which is very scarce in tropical
climate region.