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Abstract

The current study is a laboratory investigation to estimate the levels of activity concentrations of Naturally Occurring Radioactive Materials (NORM) in groundwater in the Dukhan area in the State of Qatar. The primary radionuclide associated with clear gamma-ray decay signatures of concern in NORM wastes is 226Ra (from the 238U decay series) and its decay progenies 214Pb and 214Bi. Previous studies which were conducted on radioactivity concentration in soil in the State of Qatar have shown elevated levels of enhanced radioactivity in the area, North-West Dukhan, known for its oil fields. With the original aim of investigating the correlation between the underlying geological background and any measured elevation in the activity concentration of 226Ra, an anomalously high value of 226Ra activity had been observed for a number of measured samples in our earlier work, in this particular area and in particular. The weighted mean value of the activity concentrations of 226Ra in one of the samples was found to be around approximately a factor of 10 higher than the accepted worldwide average value of 35 Bq/kg. Our first study reported a value of about 201.9 ± 1.5Stat. ± 13Syst. Bq/kg for 226Ra in one sample,1 while our further and focused (smaller grids) investigation in the latest work determined a measured value for 226Ra of about 342.00 ±  1.9Stat. ± 25Syst. Bq/kg in a sample taken from the same locality.2 This is significantly higher than all the other investigated soil samples in the current and previous work and was likely to be in a heterogeneous distribution. This was found to be attributed to the weak correlation between the levels of activity concentration of 226Ra and the type of soil in this area implying that the increased 226Ra concentration arises from discharging co-produced water directly to land surface in this area. A preliminary study on the level of natural radionuclides in eight groundwater samples for this specific area using five cutting edge techniques in the national and collaborating laboratories will be presented. About half of those samples were collected from Dukhan farms where the groundwater was used for irrigation. Measurements for 222Rn concentrations in groundwater will be conducted using Rad-7 and a Liquid Scintillator Counter (LSC) at the Physics Department, Faculty of Sciences, Princess Nora Bint Abdul Rahman University, KSA. The activity concentration of 210Po and 210Pb will also be analyzed using alpha spectrometry and LSC at the National Physical Laboratory, UK. Gamma measurements using Low-level HPGe Detector will focus on activity concentration levels of 228, 226Ra and their decay progenies 214Bi, 214Pb, 228Ac, 212Pb and 208Tl and they will be conducted at the Radiation Measurements Laboratory, Ministry of Environment, Qatar. A general chemical analysis using ICP-MS will be conducted at the laboratory of Qatar Environment and Energy Research Institute (QEERI) in order to support the radiological analysis in the project. The results of this study will be essential to further clarify the reasons behind this elevation in this area. In addition, it will help in characterizing the areas of concern and explore the beneficial use and the suitable and feasible treatment options of the co-produced water and positively contributing to the water security target.

References

1. Al-Sulaiti, H., Regan P. H., Bradley D. A., Malain D., et al., A preliminary report on the determination of natural radioactivity levels of the State of Qatar using high-resolution gamma-ray spectrometry. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment (NIM-A), 2010. 619(1–3): p. 427–431.

2. Huda Al-Sulaiti, Tabassum Nasir, K.S. AlMugren, et al., Determination of the Natural Radioactivity Levels in North West of Dukhan, Qatar Using High-Resolution Gamma-ray Spectrometry, Proceedings of the 8th International Topical Meeting on Industrial Radiation and Radioisotope Measurement Applications (IRRMA-8) Applied Radiation and Isotopes, July 2012, Volume 70, Issue 7, p. 1344–1350.

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/content/papers/10.5339/qfarc.2016.EEPP1827
2016-03-21
2019-11-15
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