MEASUREMENTS AND COMPARISON OF 222RN CONCENTRATIONS LEVEL IN SOIL ACCORDING TO THE SOIL TEXTURE AND SERIES IN NORTH SEBERANG PERAI AREA IN PULAU PINANG
| Presenter | : | SITI AISHAH AR. AZMI |
| : | - | |
| Date | : | 19 / 6 / 2007 |
| Time | : | 2.00 PM |
| Venue | : | ( CEMACS ) CONFERENCE ROOM, SCHOOL OF PHYSICS |
| Sypnosis | : | 222Rn is a naturally occurring radioactive noble gas, originating from the decay of uranium, 238U, in rocks, soils and minerals. The 222Rn and its solids decay products are responsible for about 50% of annual natural radiation dose of the population. The purpose of this study was to measured the 222Rn concentration from soil especially sand, silt and clay samples and relate it to relative humidity and soil particle size. This study also measured 222Rn concentration in three stages of 222Rn concentration (high risk, medium risk and low risk), 6 types of soil’s texture, 6 types of soil’s series and three types of formation. The soil samples were taken from 111 sites in the area of Seberang Perai Utara, Penang at 30 cm below the soil’s surface. The 222Rn concentrations were measured using continuous active sampling’s method. Particle size distribution of the soil was determined using a sieve and pipette methods. The study showed that 222Rn concentration found to be controlled by relative humidity and soil particle size. The 222Rn concentration values vary from 1.2 pCi/l to 10.9 pCi/l. The highest level of 222Rn concentration were found at Kg. Ekor Kucing area, while the lowest was from Kg. Paya Keladi area. There is a positive correlation between relative humidity and 222Rn concentrations, with a correlation coefficient of R2 = 0.99. The relations between clay and silt contents with 222Rn concentrations showed positive correlation of R2 = 0.95 and R2 = 0.91 respectively. However, results showed a negative correlation between sand content and 222Rn concentration, with a correlation coefficient of R2 = 0.94. The results showed that, for 222Rn concentration range at < 2pCi/l, 222Rn concentration mean was 1.6 pCi/l, whereas for 222Rn concentration ranges at ≥ 2 pCi/L and < 4 pCi/l, and ≥ 4 pCi/l, the 222Rn concentration mean were 2.9 pCi/l and 6.1 pCi/l respectively. The results also showed that the highest value of 222Rn concentration mean in soil’s texture recorded by silty clay was 4.3 pCi/l whereas the others were sandy clay (4.2 pCi/l), clay (4.1 pCi/l), silt loam (3.7 pCi/l), clay loam (2.8 pCi/l) and sandy loam (2.2 pCi/l). The highest value of 222Rn concentration mean in soil’s series recorded by Telemong-Akob-Local Aluuvium’s siries was 4.3 pCi/l. Other findings showed Sogomana-Sitiawan-Manik’s series (4.0 pCi/l), Sedu-Parit Botak-Linau’s series (2.6 pCi/l), Chengai’s series (4.1 pCi/l) dan Holyrood-Lunas’s series (3.2 pCi/l) and Kranji’s series (2.1 pCi/l). The results also showed that the highest value of 222Rn concentration mean in formation recorded by Beruas’s formation (4.3 pCi/l), whereas Gula’s formation showed the lowest value of 222Rn concentration mean (3.5 pCi/l). Then, Simpang’s formation charted 222Rn concentration mean about 3.8 pCi/l. |
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