Distribution of naturally occurring radionuclides activity concentration in East Malaysian marine sediment

• Published in: Applied radiation and isotopes Vol. 67; no. 4; pp. 630 - 635
• Main Authors: Yii, M.W., Zaharudin, A., Abdul-Kadir, I.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-04-2009
• Subjects: East Malaysia; External hazards value; Geologic Sediments - chemistry; Malaysia; Marine; Marine sediment; NORM; Radioisotopes - analysis; Malaysia; ISEW, Borneo, Sabah; ISEW, Borneo, Sarawak; ISEW, Malaysia; External hazards value; NORM; Marine sediment; East Malaysia
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2008.11.019

Studies of naturally occurring radioactive materials (NORM) distribution of
226Ra,
228Ra and
40K in East Malaysia were carried out as part of a marine coastal environment project. The results of measurements will serve as baseline data and background reference level for Malaysia coastlines. Sediments from 21 coastal locations and 10 near shore locations were collected for analyses. The samples were dried, finely ground, sealed in a container and stored for a minimum of 30 days to establish secular equilibrium between
226Ra and
228Ra and their respective radioactive progenies. They were counted using a high-purity germanium (HPGe) spectrometer covering the respective progeny energy peak. For
40K, the presence of this was measured directly via its 1460
keV energy peak. The concentration of
226Ra,
228Ra and
40K in samples obtained from coastal Sarawak ranged between 23 and 41 (mean 30±2)
Bq/kg, 27 and 45 (mean 39±4)
Bq/kg and 142 and 680 (mean 462±59)
Bq/kg, respectively. Meanwhile, the concentration of
226Ra,
228Ra and
40K for samples obtained from coastal Sabah ranged between 16 and 30 (mean 23±2)
Bq/kg, 23 and 45 (mean 35±4)
Bq/kg and 402 and 842 (mean 577±75)
Bq/kg, respectively. For the Sarawak near shore stations, the concentration of
226Ra,
228Ra and
40K ranged between 11 and 36 (mean 22±2)
Bq/kg, 21 and 65 (mean 39±5)
Bq/kg and 149 and 517 (mean 309±41)
Bq/kg, respectively. Meanwhile, the concentration of
226Ra,
228Ra and
40K for samples obtained from Sabah ranged between 9 and 31 (mean 14±2)
Bq/kg, 10 and 48 (mean 21±3)
Bq/kg and 140 and 580 (mean 269±36)
Bq/kg, respectively. The calculated external hazard values of between 0.17 and 0.33 (less than unity) showed that there is little risk of external hazard to the workers handling the sediments.