[en] Co-precipitation method is suitable mean for determination of gross alpha activity in water with high salt compounds. Alpha emitters which are Actinides and those in Uranium-Radium series are co-precipitated with barium carrier and iron carrier. Although the activity is not indicative of any specific nuclides presented but it can be used as an index to the radioactive contamination of the waters

[en] Result obtained from radiometric research carried out from 1988 - 1995 in the vicinity of a Rare-earth Research and Development Center are provided. Parameters under investigation were gross-alpha, gross-beta, 226 Ra, natural uranium and tritium concentrations in surface, rain and underground water. Radioactivity levels were found relatively low and can be characterized as a local based line. This will enable us in a later stage to monitor the change caused by the Rare-earth Research and Development Center operation

[en] The profiles of ¹³⁷ Cs sediment cores from OAEP pond were measured. Most of ¹³⁷ Cs, due to the release of treated liquid radioactive waste from OAEP waste treatment plant, was found to remain practically fixed in the upper 30 cm of sediment since 1961. The profile has two slopes in semilogarythemic scale, i.e. the sum of two exponentials inconsistent with a number of previous experiment. The concentration of ¹³⁷ Cs in fish, fish bone and snail fish are reported which the result in line with the previous measurement (Kusuma Sriyotha, 1982) confirm the precision of our analytical result

[en] Studies concerning the radioactivity quality of artesian water are performed by analyzing gross alpha, gross beta, and radium-226 in the water samples. Results of three aquifers monitored namely: Phra Pradang (depth 100-150 meters), Nakhorn Luang (depth 151-200 meters) and Nonthaburi (depth 201-250 meters) were found to be: gross alpha; 0.023+-0.004, 0.024+-0.002 and 0.024+-0.01 becquerel per litre respectively; gross beta; 0.070+-0.009, 0.196+-0.03 and 0.156+-0.003 becquerel per litre respectively and radium-226; 0.012+-0.0012, 0.16+-0.0003 and 0.014+-0.0002 becquerel per litre respectively. The weighted mean of the radioactivity level in the three aquifers were proposed as the baseline level in the artesian well water in Thailand. The baseline levels are 0.024+-0.001, 0.176+-0.002 and 0.015+-0.0002 for gross alpha, gross beta, and radium-226 respectively. In conclusion, at this present level, the Bangkok area artesian well water is considered radiologically safe for drinking within the US. Environmental Protection Agency drinking water standards (US.EPA). Twelve reference water solutions from US.EPA were analyzed for analytical quality assurance. The total number of 166 water samples from 64 artesian well at a depth of 100 and 300 meters were collected by the Bangkok Metropolitan Water works between December 1983 to June 1985

[en] Activities of ²²⁶ Ra and natural U in mine discharge, Krabi and water from natural resources nearby were investigated. The average ²²⁶ Ra activities in water upstream, downstream and site discharge were 0.0052 ± 0.0002, 0.0272 ± 0.0003 and 0.0342 ± 0.0002 Bq/l and that for natural U were 0.0125 ± 0.0007, 0.0348 ± 0.0008 and 0.0934 ± 0.0004 Bq/l, respectively. Mine discharge contain higher activity became diluted when discharged into the natural water resources. Based on the safety level stated by the US.EPA., the mine operating did not cause any radiological effect onto the surrounding environment. There is evidence of leaching of radioactivity from coal mineral. Therefore, radiological study is necessary in order to provide information relevant to possible impacts of coal mining

[en] In this study sediment core samples from 8 stations in the Gulf of Thailand were collected during September 1992 - August 1994. Sediment cores have been dated by ²¹⁰Pb dating method. Aliphatic and aromatic hydrocarbon have been analyzed by GC and GC/Ms technique. Total n-alkane in surface sediment were 0.237 - 2.210, 0.672, 0.458, and 0.118 - 0.171 μg/g dry weight with the average of 0.940, 0.672, 0.458, and 0.144 μg/g dry weight for area 1,2,4 and 3 respectively

[en] In the normal operation of the Thai Research Reactor located inside office of Atomic Energy for Peace, trivial quantities in volume and activity of low-level liquid waste are discharged to the fresh-water system under authorization. It is the purpose of this report to estimate the doses to members of the public from the releases to the surface water environment. Environmental monitoring program is carefully conducted to measure the activity of radionuclides in the pathways to man. The only potential pathway contributing to the radiation dose by the local members in the vicinity or OAEP is the consumption of fresh-water plant, swamp cabbage, white stem Ipomoca reptans. The calculated committed effective dose to members of the public who are likely to receive maximum dose are 0.11 μSv. The result shows that normal operation of the research reactor insignificantly contributes to the annual effective dose equivalent limit for the public recommended by the International Commission on Radiological Protection (1991), that is, 1 mSv y^-1

No abstract available

No abstract available

[en] Levels of ²¹⁰Po and its effective dose in green mussel (Perna viridis) collected from mussel farming area at the Samut Sakhon province during the period of 2012-2013 are presented. Several parameters including maximum shell length and the physiological performance of mussels using condition index and physical properties of seawater (pH, salinity, conductivity, TDS, DO and cation-anion elements) were measured. Each individual mussel was measured on its maximum shell length which was adopted as size class. The activity concentration of 210Po was determined spectroscopically through its 5.30 MeV alpha particle emission, using ²⁰⁹Po as an internal tracer. The ²¹⁰Po activity concentration in mussels was found to vary between 1.044 and 6.951 Bq.kg-1 wet weight. The ²¹⁰Po concentration was higher in smaller sized classes (>35 mm) and lowest in larger ones (40-70 mm). This confirms that larger mussels have lower 210Po levels on a weight basis. The ²¹⁰Po body burden (activity per mussel) ranged from 1.035 to 17.183 mBq. Contrary to the ²¹⁰Po concentrations, results of the body burden revealed the lower activities in smaller sized mussels (>35 mm) and the higher in larger sized ones (40-70 mm). The type of fluctuations observed with ²¹⁰Po concentrations are interpreted as a seasonal effect. Total annual effective ²¹⁰Po dose due to mussel consumption was calculated to be in the range of 3.081 to 16.401 μSv. Based on the international guideline, the average dose calculated due to ²¹⁰Po in mussels of Samut Sakhon would not pose any significant radiological impact on human health and the mussels are considered to be safe for intake.