Ahmad, Nisar
(2015)
Natural Radioactivity, Radon Concentration And Heavy Metals In Soil And Water In Kedah, Malaysia.
PhD thesis, Universiti Sains Malaysia.
Abstract
Radioaktif semula jadi, kepekatan 222Rn dan logam berat (Pb, Ni, Cr, Cd dan As) telah ditentukan daripada 31 tanah tidak ditanam dengan sayuran, 42 tanah yang ditanam dan 51 air minuman dan air saliran untuk menyelidik kesan-kesan aktiviti manusia di Sungai Petani, Baling dan Kulim di Negeri Kedah, Malaysia. Kajian ini dijalankan dengan menggunakan Germanium berketulenan tinggi (HPGe) untuk mengukur keradioaktifan semula jadi, CR-39 NTDs dan Radon Monitor Berterusan (CRM) untuk mengukur kepekatan 222Rn dalam tanah, Rad-7 untuk mengukur kepekatan 222Rn dalam air dan Penyerapan Atom Spektrometer (AAS) untuk mengukur tahap logam berat dalam sampel tanah dan air. Kepekatan aktiviti purata 226Ra, 232Th dan 40K didapati lebih tinggi di dalam tanah tanaman dan berada dalam lingkungan yang dilaporkan bagi negara-negara lain di seluruh dunia. Berdasarkan kepekatan aktiviti 226Ra, 232Th dan 40K yang diselidik, indeks hazad luaran (seperti indeks gama (Iγ), aktiviti setara radium (Raeq), indeks hazad luaran (Hex) dan dos luaran di luar ruangan (Dout)), indeks hazad dalaman (seperti indeks alfa (Iα), indeks hazad dalaman (Hin) dan dos luaran di dalam ruangan (Din)) dan dos berkesan tahunan (seperti dos luar berkesan (Eout) dan dos dalaman berkesan (Ein)) daripada sampel tanah telah dijumpai.
Natural radioactivity, 222Rn concentration and heavy metals (Pb, Ni, Cr, Cd and As) were determined in 31 uncultivated soil, 42 cultivated soil and 51 drinking and irrigated water to investigate the effects of human activities in Sungai Petani, Baling and Kulim in the state of Kedah, Malaysia. This study was conducted using High Purity Germanium (HPGe) to measure natural radioactivity, CR-39 NTDs and Continuous Radon Monitor (CRM) to measure 222Rn concentration in soil, Rad-7 to measure 222Rn concentration in water and Atomic Absorption Spectrometer (AAS) to measure the level of heavy metals in soil and water samples. The average activity concentrations of 226Ra, 232Th and 40K were found higher in cultivated soil and to be within those reported for other countries worldwide. Based on the investigated activity concentrations of 226Ra, 232Th and 40K, outdoor hazard indices (such as gamma index (Iγ), radium equivalent activity (Raeq), external hazard index (Hex) and outdoor external dose (Dout)), indoor hazard indices (such as alpha index (Iα), internal hazard index (Hin) and indoor external dose (Din)) and annual effective doses (such as outdoor effective dose (Eout) and indoor effective dose (Ein)) from soil samples were found.
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