A trial study had been conducted to determine the particulate form of 137 Cs in seawater surrounding East Malaysia. Large volume of seawater was filtered at a flow rate of 15 liters/min through the copper hexacyanoferrates (II) impregnated filters. These filters were ashed and counted using the gamma spectrometry system to determine the dissolved 137 Cs activity. It was found that the particulate form of 137 Cs consists of 20 to 49 % of the total 137 Cs activity concentrations. Some reasonable explanations for higher particulate percentage such as sampling locations, high water flow-rate, and large volume of seawaters were further discussed. It is hope that the result of this study will help to build a better understanding about the usage of impregnated filters to study dissolved 137 Cs activity concentrations.
The issue of water quality is a never ended issue and becoming more critical when considering the presence of natural radionuclides. Physical parameters and the levels of radionuclides may have some correlation and need further attention. In this study, the former tin mine lake in Kampong Gajah was chosen as a study area for its past historical background which might contribute to attenuation of the levels of natural radionuclides in water. The water samples were collected from different lakes using water sampler and some in-situ measurement were conducted to measure physical parameters as well as surface dose level. The water samples were analyzed for its gross alpha and gross beta activity concentrations using liquid scintillation counting and in-house cocktail method. Gross alpha and beta analyzed using in-house cocktail are in the range of 3.17 to 8.20 Bq/L and 9.89 to 22.20 Bq/L; 1.64 to 8.78 Bq/L and 0.22 to 28.22 Bq/L, respectively for preserved and un-preserved sample. The surface dose rate measured using survey meter is in the range of 0.07 to 0.21 μSv/h and 0.07 to 0.2 μSv/h for surface and 1 meter above the surface of the water, respectively.
This study was performed to observe the variation in the distribution of 210Po,210Pb and 210Po/210Pb activity ratio throughtheir vertical profile of the sediment cores takenat surrounding Sungai Linggi estuary. Five sediment cores were takenin February 2011 and were cutto an intervalof 2 cm layer. Activity concentrations of 210Po and 210Pb were determined using alpha radiochemical analysis and gamma direct measurement, respectively. Generally, the measured activity of 210Po, 210Pb and 210Po/210Pbwere in the ranges of 22.73 –139.06 Bqkg-1dw., 37.88 –176.24 Bqkg-1dw.and 0.23 –1.34, respectively. The variation in the distribution profile for the radionuclides are believed to be influencedby human activities such as agriculture, fertilizer, vehicles, burned fuel fossil and forest, industrialand others via river input from land-base.Other factor is due to organic mattercontent played importantrole as the geochemical carrier to transportthose radionuclides at study area. It was provedthat hasa strong correlation between the radionuclide distribution and the sedimentcomposition of organic matter.Furthermore, in those rangesreflectedthat 210Pb activities were higher than210Po with an activity ratio average of 0.79. This is probably due to dramatic increase of excess 210Pb supplied from atmospheric deposition, in situ decay of 226Ra and as a result of diagenetic remolibilazationof 210Pbin deeper layesof the sediment column. Thus, thosefactors are majorcontributions on thevariation of 210Po and 210Pb in the sediment core at surrounding Sungai Linggi estuary.
An improved laboratory technique for measurement of polonium-210(
210Po) in environmental
samples has been developed in Radiochemistry and Environmental Laboratory (RAS), Malaysian
Nuclear Agency. To further improve this technique, a study with the objectives to determine the
optimum conditions for
210Po deposition and; evaluate the accuracy and precision results for
the determination of 2 1 0 P o in environmental samples was carried-out. Polonium-210 which
is an alpha emitter obtained in acidic solution through total digestion and dissolution of samples
has been efficiently plated onto one side of the silver disc in the spontaneous plating process for
measurement of its alpha activity. The optimum conditions for deposition of 210Po were achieved
using hydrochloric acid (HCl) media at acidity of 0.5 M with the presence of 1.0 gram hydroxyl
ammonium chloride and the plating temperature at 90
oC. The plating was carried out in 80 mL
HCl solution (0.5 M) for 4 hours. The recorded recoveries obtained using 2 0 9 P o tracers in
the CRM IAEA-385 and environmental samples were 85% – 98% whereby the efficiency of the
new technique is a distinct advantage over the existing techniques. Therefore, optimization of
deposition parameters is a prime importance to achieve accuracy and precision results as well as
economy and time saving
Anthropogenic airborne depositions of 210Po,
210Pb and 210Po/210Pb in the mosses and surface soils
collected at the vicinity of a coal-fired power plant were studied. The purpose of the study was to
determine activity concentrations of 210Po,
210Pb and 210Po/210Pb for assessing their variation
accumulation in the mosses and surface soils collected at the vicinity of a coal-fired power plant.
Other purposes were to determine their concentration factor (CF) in relation to track the potential
source of those radionuclides and to identify most suitable moss species as a biological indicator
for atmospheric deposition contaminants. In this study, different species of moss Leucobryum
aduncum, Campylopus serratus, Syrrhopodon ciliates and Vesicularia montagnei were collected in
May 2011 at the area around 15 km radius from Tanjung Bin coal-fired power plant located in
Pontian, Johor. The activity concentrations of 210Po,
210Pb and 210Po/210Pb in mosses were in the
range of 76.81 ± 4.94 – 251.33 ± 16.33 Bq/kg dry wt., 54.37 ± 3.38 – 164.63 ± 11.64 Bq/kg dry wt.
and 1.10 – 2.00, respectively. Meanwhile the ranges for those radionuclides in the surface soil
were 33.53 ± 2.10 – 179.67 ± 12.15 Bq/kg dry wt., 20.55 ± 1.33 – 106.62 ± 6.64 Bq/kg dry wt. and
1.61 – 2.44, respectively. Corresponding high ability of Leucobryum aduncum to accumulate more
210Po and 210Pb, wide geographical distribution, most abundant and high CF, therefore, the
findings can be concluded this species was the most suitable as a biological indicator for
atmospheric deposition contaminants such as 210Po and 210Pb. Furthermore, it is clear the
accumulation of 210Po and 210Pb in mosses might be supplied from various sources of atmospheric
deposition such as coal-fired power plant operation, industrial, agriculture and fertilizer activities,
burned fuel fossil and forest; and other potential sources. Meanwhile, the
The distribution, enrichment and pollution status of metals in sediment cores from the Sabah-Sarawak coastal waters were studied. Seven sediment cores were taken in July 2004 using a gravity box corer. The metals of Cu, Zn and Pb were analyzed by ICP-MS to assess the pollution status of the sediments. The sediment fine fraction and organic carbon content was also analyzed. Enrichment Factor (EF), Geoaccumulation Index (Igeo) and Pollution Load Index (PLI) was calculated as criteria of possible contamination. The results showed that collected sediments were composed with clay, silt and sand as 12 – 74%, 27 – 72% and 0 – 20%, respectively. Meanwhile, organic carbon contents were relatively low and constant over time, based on sediment depth profiles, and it did not exceed 5% at any sampling station. The average metal concentrations in sediment cores at all sampling station were distributed in the ranges of 1.66 ± 1.36 – 6.61 ± 0.12 μgg-1 for Cu, 26.55 ± 1.04 – 57.94 ± 1.58 μgg-1 for Zn and 3.99 ± 0.10 – 14.48 ± 0.32μgg-1 for Pb. According to calculations of EF, Igeo and PLI, it can be concluded that concentrations of Cu, Zn and Pb were not significantly affected by pollution from anthropogenic sources at the seven sampling locations. Thus, the metal content of Cu, Zn and Pb in sediment should not cause pollution problem to the marine environment of Sabah-Sarawak coastal waters and further response measures are not needed.
Recently, Malaysia has taken a positive step toward providing a better water quality by introducing more water quality parameters into its Water Quality Standard. With regard to the natural radionuclides that may present in the water, 3 parameters were introduced that is gross alpha, gross beta and radium which need to be measured and cannot exceed 0.1, 1.0 and 1.0 Bq/L respectively. This study was conducted to develop a more practical method in measuring these parameters in aqueous environmental samples. Besides having a lot of former tin mining areas, some part of Malaysia is located on the granitic rock which also contributes to a certain extent the amount of natural radionuclides such as uranium and thorium. For all we know these two radionuclides are the origin of other radionuclides being produced from their decay series. The State of Kelantan was chosen as the study area, where the water samples were collected from various part of the Kelantan River. 25 liters of samples were collected, acidify to pH 2 and filtered before the analysis. Measurement of these parameters was done using liquid scintillation counter (LSC). The LSC was set up to
the optimum discriminator level and counting was done using alpha-beta mode. The results show that gross alpha and beta can be measured using scintillation cocktail and radium and radon using extraction method. The results for gross alpha, gross beta, 222Ra and 226Ra are 0.39-6.42, 0.66-16.18, 0.40-4.65 and 0.05-0.56 Bq/L. MDA for gross alpha, gross beta and radium is 0.03, 0.08 and 0.00035 Bq/L respectively.
Kajian ini dijalankan untuk melihat variasi taburan 210Po dan 210Pb melalui profil menegak aktivitinya, serta nisbah aktiviti 210Po/210Pb di dalam teras sedimen yang diambil di beberapa stesen persampelan pesisir pantai perairan Sarawak. Didapati profil taburan radionuklid tersebut dalam teras sedimen adalah berubah-ubah mengikut lokasi persampelan dan telah dibuktikan melalui analisis ANOVA yang menunjukkan bahawa terdapat perbezaan bererti pada 95% aras keyakinan bagi aktiviti 210Po (p = 0.000), 210Pb (p = 0.035) dan 210Po/210Pb (p = 0.000) di semua lokasi kajian. Secara umumnya, aktiviti 210Po dan 210Pb yang diukur masing-masing dalam julat 337 ke 2460 Bq/kg, 11 ke 84 Bq/kg di SR 01; 224 ke 2008 Bq/kg, 6 ke 80 Bq/kg di SR 02; 119 ke 1595 Bq/kg, 6 ke 84 Bq/kg di SR 03; 241 ke 2294 Bq/kg, 5 ke 82 Bq/kg di SR 04 dan 175 ke 1340 Bq/kg, 4 ke 44 Bq/kg di SR 05. Merujuk kepada julat tersebut, didapati aktiviti 210Po adalah lebih tinggi daripada aktiviti 210Pb dengan purata nisbah 210Po/210Pb di semua stesen adalah melebihi satu, iaitu dalam julat 20 ke 35. Variasi profil taburan radionuklid tersebut dipercayai dipengaruhi oleh beberapa faktor sekitaran dan telah dibuktikan terdapat korelasi yang kuat di antara taburan radionuklid dengan komposisi sedimen jenis kelodak (210Po:r = 0.701 dan 210Pb: r = 0.648), kedalaman air (210Po: r = -0.647) dan jarak stesen dari daratan (210Po: r = 0.746 dan 210Pb: r = 0.975). Oleh itu, dapat disimpulkan bahawa faktor-faktor tersebut merupakan penyumbang utama ke atas perubahan yang berlaku kepada taburan 210Po dan 210Pb.
The most commonly used techniques of alpha and gamma spectrometry were performed to measure
210Pb activity in marine sediment core as a comparison. Alpha analytical technique measured the
activity of 210Pb from it’s in-grow grand-daughter 210Po after a chemical separation, assuming
radioactive equilibrium between the two radionuclides. Meanwhile, gamma analysis technique
allows direct measurement, non-destructive and no preliminary chemical separation. Through the
comparison, it is found that both alpha and gamma analysis techniques were slightly difference.
Overall, the results from alpha analytical technique were basically higher than those from the
gamma analytical techniques. Some logical argument had been discussed to explain this situation.
In routine analysis, the analytical technique used should be chosen carefully based on advantages
and disadvantages of the each technique and analysis requirements. Therefore, it is recommended to
determine exactly the needs and purpose of analysis and to know the sample history before decide
the appropriate analytical technique
Results ofthe bioaccumulation study anddose assessmentof Th-232 in whole-body Anabas testudineus are presented. The objective of this study was to evaluate the effect of Th-232 concentration activity on the laboratory bioaccumulation and total dose rate in Anabas testudineus. Anabas testudineus adults were exposed to different waterborne Th-232 levels: 0 Bq/L (control), 50 Bq/L and 100 Bq/L for 30 day (uptake phase). Whole-body uptakesof Th-232 in Anabas testudineuswere calculated and total dose ratesusing ERICA Assessment Tool were also estimated. The results showed the increase of waterborne Th-232 concentration corresponded to a progressive increase of Th-232accumulation and total dose rate (internal and external) in whole-body Anabas testudineus.Considering the ERICA dose rate screening value of 10 μGy/h, the findings can be concluded the estimated of total dose rate (0.38 –1.29μGy/h) in Anabas testudineuswasin orderof small magnitude. Nevertheless, these results showed that the Anabas testudineushas a potential to accumulate thorium.
On March 11, 2011, a serious accident occurred in Daiichi nuclear reactor plant, Fukushima,
Japan which caused radioactive materials been released into the atmosphere in the form of
aerosols and dust particles. Sea water around the plant was also found contaminated with high
radioactivity readings. These radioactive materials could be transported by the winds and ocean
current across international borders and cannot be controlled by human. Thus, a continuous
monitoring activity of radionuclide content in the air and sea water needs to be conducted by the
authorities. In addition to radioactivity monitoring, Malaysia should also control the entry of
contaminated food in order to prevent radionuclide ingestion by human. The radionuclide 131I,
134Cs and 137Cs were used as a measure of pollution levels and counted with gamma spectrometry
using standard analysis method suggested by AOAC International. In this paper, details description
of the role of Radiochemical and Environment Group, Nuclear Malaysia who’s responsible in
analyzing the radioactivity in the food samples due to Fukushima Daiichi, Japan accident was
included. The radioactivity limit adopted and analysis results from this monitoring were discussed