The source of anomalous radioactivity in the springs bordering the Sea of Galilee, Israel

• Published in: Journal of environmental radioactivity Vol. 85; no. 1; pp. 137 - 146
• Main Authors: Ilani, S., Minster, T., Kronfeld, J., Even, O.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2006; Elsevier
• Subjects: Applied sciences; Biological and physicochemical phenomena; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Freshwater; Groundwater; Hot springs; Israel; Natural water pollution; Oil shale; Pollution; Pollution, environment geology; Radioactivity; Radiometry; Radium; Radon; Rift Valley; Sea of Galilee; U-series disequilibrium; Water Pollutants, Radioactive - analysis; Water treatment and pollution; Asia; Israel; Israel, Galilee, Kinneret L; U-series disequilibrium; Groundwater; Rift Valley; Radon; Hot springs; Sea of Galilee; Oil shale; Radium; Radioactivity; Natural origin pollution; Radioactive pollution; Radioisotope; Brackish water; Water spring; Pollution source; Geogenic factor; Radiometry; Water pollution; Hot source; Ground water
• ISSN: 0265-931X; 1879-1700
• DOI: 10.1016/j.jenvrad.2005.07.003

Situated within the Jordan Rift Valley, along the shores of Lake Kinneret (Sea of Galilee) which serves as the national water reservoir of Israel, are saline hot springs that are notable for their enrichment in radon and radium. Though the anomalous radioactivity has been known for almost half a century, the source of the radioactive anomalies has been a subject of conjecture. Radiometric analysis of a rock core drilled through Mt. Arbel, situated to the west of the lake, reveals that the oil shale sequence of the Senonian En Zetim and Ghareb formations is strikingly deficient in radium. Mt. Arbel has been cut by Rift Valley related faults that serve as conduits for ascending brines. The organic matter enriched sequence is encountered in the subsurface at elevations lower than the water level of the nearby radioactive enriched hot springs. It is thus concluded that hot ascending brines underlying the lake flush through the organic matter enriched sequence and remove a substantial percentage of 226Ra from the uranium enriched organic material, before draining to the outlets of the springs. Saline springs that are in contact with organic matter enriched sequence show excess of radium and radon, while fresh water springs in the same stratigraphic position show only excess of radon.