Radiometric and Geophysical Investigations on Exposure Levels and Excess Cancer Risk in Kargi-Kenya

Radiation is considered one of the possible causes of cancer disease with natural background sources including cosmic, terrestrial and internal radiation. A number of cancer disease cases have been reported in Kargi with their causes not properly documented. The present work characterized the radioactivity in soil and water, to find out possible causes of radiation in KARGI-KENYA by studying magnetic intensities, anomalous zones with depth to magnetic sources and delineating subsurface structures. A total of 117 soil and 14 water samples were collected from the entire area and analysed for radionuclides due to 40K, 232Th and 226Ra. Measurement methods of proton magnetometer and gamma spectrometry employing a high purity germanium (HPGe) detector were employed basically to evaluate the magnetic survey and radiological hazard of radioactivities respectively. A total of 51 magnetic field measurements were taken on the eastern part of Kargi, a place suspected to have more concentration of radionuclides. The results showed that there could have been a fractionation during weathering period or metasomatic activity of the radioelements involvement. This study also reveals that the mining activities in the nearby study area could have affected the geologic formation causing more fracturing in rocks and pronounced subsurface structures as a result of mining that could have served as passage for leachates from pollutants as well as the level of radiation in the study area.