Leachable 226Ra in Philippine phosphogypsum and its implication in groundwater contamination in Isabel, Leyte, Philippines
Phosphogypsum (PG), the major waste material in phosphate fertilizer processing, has been known to contain enhanced levels of naturally-occurring radionuclides especially 226Ra.The lack of radioactivity data regarding Philippine phosphogypsum and its environmental behavior in the Philippine setting has brought concern on possible contamination of groundwater beneath the phosphogypsum ponds in Isabel, Leyte, Philippines. The radioactivity of Philippine phosphogypsum was determined and the leaching of 226Ra from phosphogypsum and through local soil was quantified. Level of 226Ra in groundwater samples in Isabel, Leyte, Philippines was also quantified to address the primary concern. It was found that the 226Ra activity in Philippine phosphogypsum is distributed in a wide range from 91.5 to 935 Bq/kg. As much as 5% of 226Ra can be leached from Philippine PG with deionized water. In vitro soil leach experiments suggest that the soil in the phosphate fertilizer plant area would be able to deter the intrusion of 226Ra into the water table. Compared to reported values of natural groundwater levels of 226Ra, the concentration of this radionuclide in Isabel, Leyte groundwater suggest that there is no 226Ra intrusion brought about by the presence of phosphogypsum ponds in the area.
Keywords226Ra Groundwater Leaching Liquid scintillation counting Phosphogypsum
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- Ahmed, N. K. (2004). Natural radioactivity of ground and drinking water in some areas of upper Egypt. Turkish Journal of Engineering and Environmental Science, 28, 345–354.Google Scholar
- Burnett, W. C., LaRock, P. A., Cowart, J. B., & Hull, C. D. (1995). Microbiology and radiochemistry of phosphogypsum. Florida Institute of Phosphate Research (FIPR) Report No. 05-035-115.Google Scholar
- Jankowski, J., Chruscielewski, W., Kaminski, Z., & Zak, A. (2000). Natural radioactivity of underground water supplies in the region Lodz in Poland. IRPA 10. Scientific topic-1 Natural Radiation Exposure.Google Scholar
- Nathwani, J. S., & Phillips, C. R. (1978). Rates of leaching of radium from contaminated soils: An experimental investigation of radium bearing soils from Port Hope, Ontario. Water, Air, & Soil Pollution, 9(4), 453–465.Google Scholar
- Paul, A. C., & Pillai, K. C. (1990). Leachability of radium from fertilizer and monazite process wastes. pp 83–95 In The Environmental Behavior of Radium, vol. 2. Technical Report Series No. 310, International Atomic Energy Agency, Vienna, Austria.Google Scholar
- Rutherford, P. M., Dudas, M. J., & Arocena, J. M. (1995b). Radioactivity and elemental composition of phosphogypsum produced from three phosphate rock sources. Waste Management and Research, 13, 407–423.Google Scholar
- Ulbak, K., & Klinder, O. (1984). Radium and radon in Danish drinking water. Radiation Protection Dosimetry, 7(1–4), 87–89.Google Scholar
- USEPA (1992). Potential uses of phosphogypsum and associated risks: Background information document. EPA 402-R92-002. Washington DC: USEPA.Google Scholar