Measurement of Radiation in Soil in the Middle of Gaza Strip

Abstract

In this thesis, we measured the activity of Alpha, Beta particles and Gamma Radiation in soil in the middle of Gaza Strip in general form by using five types of detectors. These detectors are:SolidStateNuclear Track Detectors (CR-39), Geiger Counter, Gamma Spectrometer, Scintillation counter and Portable Electra Plus. The middle region of Gaza Strip divided into four areas, in our survey, included Dier El Balah (D), Mughazi (M), Buriej (B) and Nusairat (N). From each area we have obtained ten of samples, each sample taken at the depth of one meter from the earth surface, the subsurface sample weight equal one kilogram. We removed the stones and roots from the samples, after that, the sample was placed in plastic bags, each sample was divided into two parts, each part was placed in a cup and CR-39 fixed on the lower surface of the cover of cup. The distance between the surface of the soil and CR-39 is very small, we put all of the samples in the saving place. The exposure time for the detectors was 60 days during the months October, November and December of 2004 to allow radon gas to come to an equilibrium level. The collected detectors were chemically etched using a 6 M (Mole) solution of NaOH, at a temperature of 700C, for 5 hours, (standard etching condition). The number of tracks per cm2 in each detector where manually counted by an optical microscope with power of (40×10). We measured the average of Gross Alpha contamination in Bq/m3. Results obtained show that the concentration of alpha activity ranges from (2.8 – 23.47) Bq/m3, the average value 6.36 Bq/m3 and standard deviation 2.73. Results obtained show that the average gross alpha contamination in Deir El Balah 8.87 Bq/m3, Mughazi 5.54 Bq/m3, Bureij 5.96 Bq/m3 and Nusairat is 5.096 Bq/m3. The collected samples exposed to Geiger counter and we put the probe of the device on the surface of each sample, we measured the pulses from the samples through 300 sec. We found that the radiation concentration in soil in the studied areas raging between (6.6-12.6) CPM (Count per Minute), the average value 11.23 CPM with standard deviation 3.11. Results obtained show that in Dier El Balah is 10.69 CPM, in Mughazi is 10.78 CPM, in Buriej is 10.57 CPM and in Nusairat is 12.88 CPM. We investigated the forty samples using Gamma Spectrometer and we found the radiation concentration to radioisotopes in our soil samples which are defined to gamma spectrometer device. The results obtained are in Deir El Balah region the average of activity for Iodine-129 isotope equal 0.59 pCi/gm this value is greater than other regions, in Mughazi region the average of activity for Iodine-125 isotope equal 1.47 pCi/gm this value is greater than other regions, in Bureij region the average of activity for Cesium-137 and Chromium-51 equal 0.68 pCi/gm and 0.78 pCi/gm respectively this values are greater than other regions, and in Nusairat region the average of activity for Cobalt-57 isotope equal 0.26 pCi/gm this value is greater than other regions. We can note that there is one sample in Deir El Balah region that has high radiation concentration from Iodine-129 of 2.45 pCi/gm. The samples there exposed to Scintillation Counter and found the spectra of each sample of the four regions. We conclude that the results for this device showed low background. After that, we measured the Alpha and Beta concentration using Electra Plus portable rate meter in the forty samples. We found that the Alpha concentration in Deir El Balah region equal 0.24 CPM, Mughazi 0.53 CPM, Bureij 0.48 CPM and Nusairat 0.43 CPM, we also found Beta concentration in Deir El Balah 26.29 CPM, Mughazi 23.87 CPM, Bureij 25.77 CPM and Nusairat 24.28 CPM. Certainly, this study was conducted to provide us with measurements and extrapolations about radiation concentration in general form in soil and try to expect the health effects that radiation might cause in the future, especially from the environmental point of view.