The otoliths of sea bass (Lates calcarifer) were sampled from 23 locations in Peninsular Malaysia in order to analyse the Sr/Ca, Mg/Ca and Ba/Ca ratios. This study found that these elements/Ca ratios in sea bass otoliths were correlated with the salinity zone (thalassic series) compared with elements/Ca ratios in ambient water. The contradictory pattern of Sr/ Ca ratios and Ba/Ca ratios in otoliths was found according to salinity zone variations. Thus, oligohaline waters showed the highest Ba/Ca ratios while the highest Sr/Ca ratios were recorded for saline waters. The terrigenous enrichment of Ba in water also affects the Ba content in otoliths. The presence of Mg in otoliths acts as a rival to Ba, thus affecting Mg and Ba deposition. Meanwhile, Ba is the tracer for salinity fluctuations based on the partition coefficient (D) and it shows significant changes. However, the elements in otoliths were found to originate indirectly from the water column. The sequence of the elements/Ca ratios in otoliths and ambient water was Sr/Ca>Mg/Ca>Ba/Ca and Sr/Ca>Ba/Ca>Mg/ Ca, respectively.
The aim of this study was to determine the accumulation of settling particles in coral reefs of Peninsular Malaysia. Settling particles were collected from the coral reefs of Port Dickson, Pulau Langkawi, Pulau Tioman, Pulau Redang and Pulau Tinggi from 2005 to 2008. The average total settling particles in Pulau Langkawi and Port Dickson was 49.8 mg/cm2/day, while for Pulau Tioman, Pulau Redang, and Pulau Tinggi was 3.5 mg/cm2/day. The results showed that accumulations rate in west coast were higher than east coast of Peninsular Malaysia. However, Pulau Tioman in the east coast received high accumulations rate of settling particles in certain times of the year due to sediment resuspension at shallow reefs caused by high energy seasonal yearly wave and monsoon.
The activity concentration of 210Po from six different samples consisting of raw charcoal, surface sediment, rainwater (suspended solids (SSrw) and dissolved phase (Drw) and estuarine water (suspended solids (SSew) and dissolved phase (Dew)), were analyzed. The activity concentration of
210Po in solid samples was between 7.63 ± 0.67 and 744.28 ± 21.12 Bqkg-1 and in dissolved samples varied between 0.34 ± 0.03 and 86.33 ± 6.51 mBqL-1. On average, 210Po activity in SSrw sample was the highest, at nearly three times its original form (charcoal). SSew and surface sediment samples were
similarly distributed between 15th March and 1st August samplings, but were relatively lower than charcoal and SSrw samples. The natural meteorological variability also enhanced 210Po distribution and dispersion to a few kilometers from the coal-fired power plant.
Various environmental samples (seawater, TSS, sediment, rainwater and fly ash) from eight different stations near Kapar coastal area were analyzed. The 210 Po activity concentrations in liquid samples (seawater and rainwater) varied between 0.34 ± 0.03 mBq L-1 to 22.44 ± 0.53 mBq L-1 . Whereas the concentrations in particulate samples (TSS, sediment and fly ash) varied between 43.79 ± 2.31 Bqkg-1 to 364.48 ± 5.43 Bqkg-1 . Results also showed the radioactivity in Kapar coastal is higher than most of Malaysian coast, reaching a factor of seven. This condition is mainly due to the operation of a coal-fired power plant nearby. This study also clarify the variability of 210 Po in environment was strongly influenced from rainfall events especially during wet seasons.
Natural radionuclides such as 210 Po and 210 Pb were analyzed in soft part of cockle (Anadara granosa) obtained from Kuala Selangor in the west coast Peninsular of Malaysia. The activity levels of both nuclides fluctuated within the size of cockles from 41.3 ± 2.5 Bq/kg to 114 ± 7 Bq/kg and 12.9 ± 1.7 Bq/kg to 96.8 ± 5.3 Bq/kg in dry weight (dwt) for 210 Po and 210 Pb, respectively. The level activity in wet weight (wwt) also varied from 8.60 ± 0.52 Bq/kg to 25.70 ± 1.63 Bq/kg and 2.47 ± 0.40 Bq/kg to 19.27 ± 1.05 Bq/kg for 210 Po and 210 Pb, respectively, probably related to the different of metabolic rate and growth of cockles. Activity ratio of 210 Po/ 210 Pb in dry weight also fluctuated from 0.93 to 6.41 with not related to the decay of 210 Pb.
Concentration of Ra-226 and Ra-228 activities in water and sediment samples were measured using the Liquid Scintillation Counter (LSC) and High Purity Germanium Gamma Spectrometry (HPGe). respectively. Concentrations of Ra-226 activity in sediment samples range from 18.93 Bg/ kg to 236.06 Bq/kg and for Ra-228 activity range from 12.59 Bg/kg to 410.60 Bq/kg. Meanwhile, concentrations of Ra-226 activity obtained in water samples range from 0.064 Bg/L to 0.199 Bq/L. These data indicate, that the distribution of Ra-228 and Ra-226 in the study area were varied from one sampling stations to another and is probably related to the contents of suspended particles.
Penentuan kepekatan aktiviti Ra-226 dan Ra-228 dalam sampel air dan sedimen dilakukan masing-masing dengan Pembilang Sintilasi Cecair (LSC) dan Spektrometri Gamma Germanium Lampau Tulen (HPGe). Kepekatan aktiviti Ra-226 dalam sampel sedimen adalah berjulat dari 18.93 Bg/kg hingga 236.06 Bq/kg dan kepekatan aktiviti Ra-228 berjulat dari 12.59 Bg/kg hingga 410.60 Bq/kg. Kepekatan aktiviti Ra-226 dalam sampel air yang diperolehi pula berjulat dari 0.064 Bg/L hingga 0.199 Bq/L. Ini menunjukkan taburan Ra-228 dan Ra-226 di kawasan kajian adalah berubah mengikut lokasi kajian dan berkemungkinan dipengaruhi oleh sifat kandungan bahan terampai.
Kajian ini dijalankan bagi mengenalpasti kepelbagaian nisbah 234U/238U yang wujud di dalam jumlah pepejal terampai (TSS) pada lapan stesen yang berbeza di Kuala Selangor, Selangor. Prosedur kajian ini melibatkan proses persampelan, pemendakan, resin penukaran anion, pemendakan elektrik dan teknik pengiraaan spektrometer alfa. Nisbah 234U/238U adalah paling tinggi di Stesen 8 (234U/238U = 2.98) dan Stesen 2 (234U/238U = 3.34) pada persampelan pertama. Manakala pada persampelan kedua julat nisbah 234U/238U adalah lebih luas iaitu antara 1.29 (Stesen 4) hingga 11.57 (Stesen 6). Ini disebabkan oleh berlakunya pergerakan 234U bersama-sama mikroorganisme di dalam fasa terampai dan berlaku proses penurunan U(VI) kepada U(IV) yang akan memendakkan uranium daripada air ke dalam sedimen.
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.
Analyses activities of 226 Ra and 228 Ra were conducted at ten stations of Pulau Redang, Malaysia. Dissolved radium isotopes such as 226 Ra and 228 Ra had shown enrichment at coastal area stations. Meanwhile, activities of both nuclides in the suspended particle matters were slightly in equilibrium with the activity ratio ranging from 0.88 – 1.86. The calculated distribution coefficient values (Kd) of 226 Ra and 228 Ra were in the range of 0.78 x 10 5 L g -1 to 5.56 x 10 5 L g -1 and 0.21 x 10 5 L g -1 to 1.86 x 10 5 L g -1 , respectively, indicate that most of the radium nuclides in the study area are strongly absorbed into the particulate phases. Therefore, low concentrations of suspended particles matter in the water column (< 10 mg L -1 ) have insignificant effects on the Kd values.
Kajian taburan sterol di Sungai Sepang Besar telah dijalankan pada 17 September 2005 dan 20 Disember 2005. Sampel sedimen telah diambil dengan menggunakan pensampel cekau dari 12 stesen untuk menentukan sumber-sumber yang berbeza bagi sterol dan untuk menentukan aras pencemaran bahan kumbahan di sungai tersebut. Kromatografi Gas-Spektrometri Jisim telah digunakan untuk menganalisis data. Hasil yang diperolehi menunjukkan kawasan Sungai Sepang Besar didominasi oleh kolesterol, β-sitosterol dan stigmasterol, manakala kawasan laut didominasi oleh ergosterol. Secara keseluruhan, Sungai Sepang Besar diklasifikasikan sebagai tercemar dengan kumbahan berdasarkan nisbah coprostanol/kolesterol yang diperolehi.
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