Assessment of 137Cs activity concentration in soil from tea plantantion areas in Cameron Highlands

Abstract

ABSTRACT

¹³⁷Cs is well known man-made radionuclide produced from nuclear industry. Nuclear weapon tests and nuclear accidents had contributed to presence of ¹³⁷Cs into the worldwide environment including Malaysia. It has spread out to the entire world through the air and water current. Since Cameron Highlands is located at high altitude, there is a better chance of the ¹³⁷Cs to settle down on the trees and later the soil underneath. In this study, the soil samples were taken at the slopes of two different tea plantation areas namely A and B. The soil samples were oven dried, ground, sieved and packed and sealed properly in plastic containers before measurement. Each plastic container contains around 450 g of sample. The measurement of ¹³⁷Cs activity concentration was done using HPGe detector gamma spectrometer. The spectrum was analyzed using Gamma Vision software to calculate the activity concentration of ¹³⁷Cs with energy peak of 661.66 keV. The activity concentration of ¹³⁷Cs found in the samples ranged from 0.23 to 1.90 and 0.11 to 3.01 Bq/kg for tea plantation A and tea plantation B, respectively. From the activity concentration of ¹³⁷Cs result, it was comparable to the others research regarding to ¹³⁷Cs in the soil around Asian.

ABSTRAK

¹³⁷Cs dikenali sebagai radionuklid buatan  manusia hasil  dari industri nuklear. Senjata nuklear dan kemalangan nuklear telah menyumbang kepada peningkatan  jumlah ¹³⁷Cs ke persekitaran di seluruh dunia termasuk persekitaran Malaysia. Ia telah merebak ke seluruh dunia melalui arus udara dan air. Disebabkan Cameron Highlands terletak di kawasan yang tinggi, ¹³⁷Cs mempunyai peluang yang lebih tinggi untuk jatuh menetap di pohon dan kemudian jatuh ke tanah dibawahnya. Dalam kajian ini, sampel tanah diambil pada lereng bukit  dari dua kawasan ladang teh yang berbeza  iaitu A dan B. Sampel tanah tersebut kemudiannya dikeringkan didalam ketuhar, ditumbuk, diayak dan dimasukkan ke dalam bekas plastik  serta disalut kemas sebelum pengukuran. Setiap bekas plastik mengandungi berat sekitar 450 g sampel. Pengukuran kepekatan aktiviti ¹³⁷Cs dilakukan dengan menggunakan spektrometer gama dengan pengesan HPGe. Spektrum dianalis dengan menggunakan perisian ‘Gamma Vision’ untuk mengira kepekatan aktiviti ¹³⁷Cs pada puncak tenaga 661.66 keV. Kepekatan aktiviti ¹³⁷Cs di dalam sampel masing-masing menunjukkan julat  0.23-1.90 dan 0.11-3.01 Bq/kg untuk  ladang teh A dan ladang teh B. Daripada keputusan kepekatan aktiviti ¹³⁷Cs, ianya sebanding dengan lain- lain kajian mengenai ¹³⁷Cs di dalam tanah di sekitar Asia.