Gamma Hazards and Risk Associated with Norm in Sediment from Amang Processing Recycling Ponds

Amang processing is an important down stream activity of tin mining noted for technologically enhancing naturally occurring radioactive materials. A study was carried out to determine the gamma radiation hazards associated with amang processing with special reference to the sediment accumulated in amang processing ponds. Twenty eight sediment samples from two amang processing plants employing the recycling close water management system were collected and analysed. The activity concentrations of Ra, Th and K in sediments were measured using gamma spectrometry analysis, with a Hyper Pure Ge-Li detector coupled to a Multi Channel Analyzer detector system. The range of mean activity concentrations of Ra, Th and K were between 40.94 – 189.58 Bq kg, 104.90 – 516.17 Bq kg and 74.8-848.0 Bq/kg respectively. The maximum activity concentrations of Ra, Th and K recorded were higher than Malaysia’s average and the world’s natural highest. Gamma Radiation Representative Level Index, I γr associated with these levels of activity concentrations of radionuclides in sediments, warrants an immediate attention from the regulatory authorities. The contribution of amang processing and the use of recycling close water management system in enhancing potential environmental radiological risk are discussed. Abstrak Pemprosesan amang merupakan satu aktiviti hiliran yang penting terutama bagi peningkatan secara teknologi bahan radioaktif semulajadi. Satu kajian telah dilakukan untuk menentukan bahaya sinaran gamma berkaitan dengan pemprosesan amang dengan merujuk kepada sedimen yang terkumpul di dalam kolam-kolam pemprosesan amang. Sebanyak dua puluh lapan sampel sedimen dari dua loji pemprosesan amang yang menggunakan sistem pengurusan air tertutup telah diambil dan dianalisis. Kepekatan keaktifan Ra, Th dan K dalam sedimen telah diukur menggunakan spektrometer gamma dengan pengesan Ge-Li hiper-tulen berganding dengan satu sistem Multi Channel Analyzer. Julat min kepekatan keaktifan bagi masing-masing Ra, Th dan K ialah di antara 40.94 – 189.58 Bq kg, 104.90 – 516.17 Bq kg dan 74.8-848.0 Bq/kg. Nilai kepekatan keaktifan maksimum yang dicatat bagi Ra, Th dan K ini adalah lebih tinggi daripada aras purata bagi Malaysia dan bagi aras tertinggi semulajadi dunia. Indeks aras wakilan sinaran gamma, Iγr berkaitan dengan aras kepekatan keaktifan radionuklida dalam sedimen yang dikaji ini menunjukkan perlunya tindakan segera pihak berkuasa. Sumbangan pemprosesan amang dan penggunaan sistem pengurusan air kitar tertutup terhadap peningkatan potensi risiko radiology dibancangkan dalam kertas ini.