Degradation of chlorpyrifos by ionizing radiation

Summary A survey was carried out to determine radioactivity concentrations and associated dose rates from the naturally occurring nuclides ²³² Th, ²³⁸U and ⁴⁰K in various surface soil formations of Alhkraje city. Samples were collected from different areas of the study, sieved through a fine mesh, sealed in 0.5-liter plastic Marinelli beaker, and measured in the laboratory for 24 hours each. From the measured g-ray spectra, radioactivity concentrations were determined for ²³² Th ranging from 5.32±2.59 to 16.40±2.04 Bq ^. kg^-1, ²³⁸U (2.87±0.18 to 18.83±0.81 Bq ^. kg^-1), ⁴⁰K (211.33±55.04 to 378.97±36.46 Bq ^. kg^-1) and ¹³⁷Cs (0 to 3.19±1.02 Bq ^. kg^-1). Absorbed dose rates in air doors were calculated to be in the range of 15.29±2.65 to 30.00±3.24 nGy ^. h^-1, the corresponding effective dose rates per person outdoors were estimated to be between 21.00±0.95 to 36.83±2.11 mSν^. y^-1, assuming a 20% occupancy factor.     

Natural radioactivity measurements in the granite rock of quarry sites,Johor, Malaysia

This study was conducted to determine the concentration of natural radionuclides in the granite rocks of selected quarry sites in Johor state, Malaysia and their possible radiological effects. The activity concentrations of ²³⁸U, ²³²Th and ⁴⁰K in the areas of study indicated varying values of ²³⁸U, ²³²Th and ⁴⁰K. The highest values of ²³⁸U and ²³²Th concentrations (67±1 and 85±2 Bq kg^?1, respectively) were observed at Kamad Quarry (IJM), whereas the highest value of ⁴⁰K concentration (722±18 Bq kg^?1) was detected in Kim Seng Quarry, while the values of activity concentration are lower in Hanson Quarry Products (Kulai) (25±0.5 for ²³⁸U, 24±0.5 for ²³²Th and 429±11 for ⁴⁰K). Overall, ⁴⁰K has the highest concentration in the granite rocks of the quarry sites, followed by ²³²Th and the least for ²³⁸U. The radium equivalent activity concentration was found in the range between 94 and 239 Bq kg^?1, the absorbed dose rate was found to be in the range between 47 and 112 nGy h^?1, and effective dose ranged from 58 to 137 μSv h^?1. Moreover, the internal and external hazard index values were given in results lower than unity.     

Radionuclides in a sediment trap and bottom sediment samples from the eastern Turkish coast of the Black Sea

Summary Radionuclide (¹³⁷Cs, ²³⁸U, ²³²Th and ⁴⁰K) concentrations were determined in a sediment trap and bottom sediment samples collected from a station at the eastern Turkish coast of the Black Sea. The specific activity of the ¹³⁷Cs radionuclide in the settling particles ranged from 0.04±0.01 to 0.10±0.02 Bq^. g^-1dry weight. The calculated flux rate of the ¹³⁷Cs was between 0.37 and 2.59 Bq^. m^-2. d^-1in the sampling periods of 2002 and 2003. The ¹³⁷Cs concentration in the bottom sediment profile were between 0.039±0.013-9.083±0.017 Bq^. g^-1dry weight in the same station. The vertical profile of the radionuclides suggests that they have little mobility during the 17 years after the Chernobyl accident.     

Natural radiation distribution of soils at Kotagiri Taluk of the Nilgiris biosphere in India

The systematic study of background radiation and the distribution of radionuclides in the environment of Nilgiris biosphere in South India, have been carried out with an objective of establishing reliable baseline data on the background radiation level of the region. Soil samples have been collected at various places of Kotagiri taluk in Nilgiris biosphere and are analyzed for radioactivity measurements of primordial radionuclides by 3"×3" NaI(TI) gamma-ray spectrometer. It is observed that the average activity of ²³²Th series, ²³⁸U series and ⁴⁰K in soil samples is found to be 102 Bq^.kg^–1, 41 Bq^.kg^–1 and 229 Bq^.kg^–1, respectively which contributes to a total gamma-dose of 86 nGy^.h^–1. Results of this systematic investigation establish the existence of wide range of variation in ²³²Th series, ²³⁸U series and ⁴⁰K activities, which may be attributable to the existence of wide variety of lithological compounds in the zone under study. The ambient gamma-radiation dose measured is found to vary from 91 to 193 nGy^.h^–1 with a mean of 142.8 nGy^.h^–1. The measured ambient gamma-dose is more than 50% of the dose calculated from soil activities, which is due to the higher cosmic ray contribution to the total dose in the environment. The data is compared with different places around the world and the results are discussed in this paper     

Effect of the natural radioactivity concentrations and 226Ra/238U disequilibrium on cancer diseases in Penang,Malaysia

Natural radioactivity measurements and assessment of radiological hazards in soil and sand samples obtained from Penang, Malaysia were carried out using the Exploranium GR-135 Plus “Identifier” Radioisotope Identification Device and high-resolution High Purity Germanium (HPGe) detector system. The activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K were found to be 184±11, 396±22, 165±14, and 835±28 Bq kg^?1 respectively, and the external gamma dose rate is 315±44 nGy h^?1 for soil samples. For sand samples, the activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K were 31±8, 62±16, 36±6, and 369±17 Bq kg^?1, respectively, and the external gamma dose rate is 66±12 nGy h^?1. To assess the radiological hazard of radioactivity present in the samples, the radium equivalent activity, annual effective dose, annual gonadal dose equivalent, external hazard, and internal indices were calculated.The Ra_eq values of soil samples were higher than the limit of 370 Bq kg^?1, which is equivalent to a gamma dose of 1.5 mSv yr^?1, whereas the Ra_eq for sand samples was lower than 370 Bq kg^?1. The calculated concentrations by HPGe spectroscopy were compared with the measured concentrations detected by a GR-135 spectrometer. The calculated and measured gamma dose rates had an ideal correlation coefficient R of 0.72. The gamma dose rates in Penang increased with the average annual age-standardized rates (ASR) for all cancers between 1994 and 2010. The effects of the pH value of soil and sand samples on natural radionuclides concentrations were investigated. The high concentration of ²²⁶Ra/²³⁸U ratio disequilibrium (²²⁶Ra/²³⁸U of 1.76–2.33) was observed in the sampling sites. Moreover, a portable continuous radon monitor (SNC, model 1029, Sun Nuclear Corporation) was used to measure the radon concentration of the soil surface. The radon concentrations were found to vary from 7 to 50 Bq m^?3. A positive correlation was observed between the radon and radium concentrations in samples measured by the SNC continuous radon monitor and HPGe detector.     

Physical and chemical investigation of water and sediment of the Keban Dam Lake, Turkey:

Summary The gross alpha- gross beta-activity, ¹³⁷Cs and ⁹⁰Sr in the water and sediment samples taken from the Keban Dam Lake, Uluova Region, was investigated in 2003 and 2004. We have found that in spring the concentration of ¹³⁷Cs in the surface water and deep sediment changed between 0.001-0.01 Bq/l (0.4-2.5 Bq^.kg^-1) that of ⁹⁰Sr between 0.0001-0.009 Bq/l (0.1-9 Bq^.kg^-1) and in autumn the values were 0.0001-0.009 Bq/l (0.4-8 Bq^.kg^-1) for ¹³⁷Cs and 0.0002-0.005 Bq/l (0.6-4 Bq^.kg^-1) for ⁹⁰Sr, respectively. The results were presented in form of iso-curves.     

Radioactivity mapping of north western areas of Pakistan

Summary A systematic study of natural and fall-out radionuclides was carried out with the environmental samples of soil, vegetation and water from some regions of North West Frontier Province (NWFP) of Pakistan. The pretreatment of the samples was performed in the laboratory using IAEA recommended methods. The analysis of gamma-emitters such as ⁴⁰K, ²²⁶Ra, ²³² Th and ¹³⁷Cs was performed with a high purity germanium detector (HPGe). For the determination of ⁹⁰Sr, a liquid scintillation counting system was used. The average specific activities of ⁴⁰K, ²²⁶Ra, ²³² Th and ¹³⁷Cs have been found to be 307±101 Bq ^. kg^-1, 10.2±3 Bq ^. kg^-1, 24±6 Bq ^. kg^-1 and 2.8±1.3 Bq ^. kg^-1, respectively, in soil samples. Vegetation samples have smaller values of specific activities and even the analysis of water samples showed values less than LLD for earlier reported radionuclides. Other parameters like hazard indices, radium equivalent activities, absorbed dose rates and effective dose equivalents have also been determined. All these parameters have values less than their respective limiting values representing that the surveyed areas have no significant hazard from health point of view. Analysis of ⁹⁰Sr for all the samples showed results below LLD. The present study provides a general background of the detectable radionuclides for the surveyed areas that will be helpful in any radiological emergency.     

Radiological significance of Pakistani marble used for construction of dwellings

Natural radioactivity in various types of marbles available in Rawalpindi/Islamabad industrial area have been assessed using HP(Ge) gamma-ray spectrometer. The concentration of ⁴⁰K, ²²⁶Ra and ²³²Th ranges from 6.15 to 159.65 Bq^.kg^-1, 1.45 to 29.34 Bq^.kg^-1 and 1.16 to 6.28 Bq^.kg^-1, respectively. The radium equivalent activity lies between 5.56 to 33.42 Bq^.kg^-1. The average external and internal indices have been found to be 0.03 and 0.05, respectively. The average absorbed dose rate at 1 m was found to be 6.53 nGy^.h^-1. The estimated annual effective dose rate for whole body was found to be 0.04 mSv^.y^-1. These values are smaller than those predicted by UNSCEAR for normal background areas. The marbles analyzed pose less health hazard as compared to Pakistani baked bricks and other construction materials.     

Dose rates and seasonal variations of 238U, 232Th, 226Ra 40K and 137Cs radionuclides in soils along Thrace, Turkey

Concentrations of ²³⁸U, ²³²Th, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs are measured in collected soil samples from various locations in the Thrace region of Turkey. The activity concentrations range from 12.82 to 101.75 Bq kg^?1 d.w. (dry weight) for ²³⁸U, from 5.16 to 73.34 Bq kg^?1 d.w. for ²³²Th, from 185.54 to 5399 Bq kg^?1 d.w. for ⁴⁰K and from 11.42 to 90.73 Bq kg^?1 d.w. for ²²⁶Ra. In addition to naturally occurring radionuclides, ¹³⁷Cs activity concentration is determined between 3.05 and 46.78 Bq kg^?1 d.w. for soil samples. Determination of the radiological hazard is achieved through calculations of the external terrestrial gamma dose rate in air (nGy h^?1) and annual effective dose rate (mSv year^?1) and the results are compared with the similar works in different countries.     

Evaluation of natural gamma radiation and absorbed gamma dose in soil and rocks of Perambalur district (Tamil Nadu,India)

The activity concentrations and absorbed gamma dose of primordial radionuclides ²³⁸U, ²³²Th and ⁴⁰K were determined employing γ-ray spectrometry in 31 soil samples from the land area earmarked for house construction in Perambalur district and 14 rock samples from quarries that supply stones for the entire district. The soil samples registered relatively a higher mean value of 13.2 Bq kg^?1 for ²³⁸U, 66 Bq kg^?1 for ²³²Th and 340.3 Bq kg^?1 for ⁴⁰K as compared to mean values for rock samples (²³⁸U—8.0 Bq kg^?1; ²³²Th—65.1 Bq kg^?1; ⁴⁰K—199.1 Bq kg^?1). The mean absorbed gamma dose rate for soil (61.4 nGy h^?1) marginally exceeded the prescribed limit of 55 nGy h^?1 while, rocks registered the mean absorbed gamma dose rate of 10.4 nGy h^?1. The mean radium equivalent activity was distinctly higher in soil (130.6 Bq kg^?1) than in rock (20.0 Bq kg^?1). However, these values were lower than the limit (370 Bq kg^?1) set by OECD for building materials. It is evident from the data that the soil and rocks do not pose any radiological risk for house constructions in Perambalur district.     

Natural radioactivity in cultivated land in the vicinity of a phosphate fertilizer plant in Nigeria

Natural radioactivity in soil and vegetable samples in cultivated land in the vicinity of an active phosphate fertilizer plant in Kaduna, Nigeria was carried out to assess the potential radiological impact of the plant on its immediate environment. The activity counting was carried out using sodium iodide gamma spectrometry. The annual committed effective dose for two vegetables in the farmlands due to uranium (²³⁸U) and thorium (²³²Th) was assessed. The mean activity concentration of radionuclides in the soil samples ranges from 20.5±7.3 to 31.6±4.1 Bq kg^?1 for ²²⁶Ra, 19.6±1.6 to 53.2±3.7 Bq kg^?1 for ²³²Th and 203.9±6.3 to 253.6±9.5 Bq kg^?1 for ⁴⁰K. The annual intake of ²³⁸U and ²³²Th from consumption of okra were 1.9 Bq kg^?1 and 5.22 Bq kg^?1 and for tomatoes 2.66 Bq kg^?1 and 5.1 Bq kg^?1 respectively. The committed effective doses from consumption of okra and tomatoes were 0.1 μSv y^?1 and 0.12 μSv y^?1 respectively.     

Radiological assessment of natural and fallout radioactivity in the soil of Chamba and Dharamshala areas of Himachal Pradesh,India

This paper presents the results of measurement of natural and fallout radioactivity in soil samples of Chamba and Dharamshala areas in Himachal Pradesh, India. Spatial distribution of ²³⁸U, ²²⁶Ra, ²³²Th, ⁴⁰K, ¹³⁷Cs was determined using High resolution gamma-ray spectrometry. The mean activity concentration in Chamba region due to ²³⁸U, ²³²Th, ⁴⁰K and ¹³⁷Cs was 32.3, 58.4, 588.3, and 10.9 Bq kg⁻¹, respectively, whereas in Dharamshala it was 35.7, 61.3, 594.9, 10.0 Bq kg⁻¹, respectively. Absorbed gamma dose rate (D) in air was calculated using appropriate dose conversion factors, which was varying from 45 to 103 nGy h⁻¹. To control the radiation exposure due to natural radioactivity in soil, if it is used as building materials, radium equivalent activity (Ra_eq) and activity index were also evaluated. Radium equivalent activity calculated for the soil ranged from 95.5 to 234.2 Bq kg⁻¹ with average of 171.0 Bq kg⁻¹.The calculated Activity concentration index was ranged from 0.34 to 0.85 with an average value of 0.64. The natural and fallout radioactivity in soil of this region is comparable with Indian average and other parts of the world. The percentage contribution of ²³⁸U, ²³²Th and ⁴⁰K and ¹³⁷Cs to the average external gamma dose rate was 22, 46, 32, 2%, respectively. This shows that the dose contribution due to fallout radioactivity is negligible as compared to the natural radioactivity.     

Activity concentrations of selected artificial and natural radionuclides in water and sediment samples from the North Western Black Sea, 1999

Radioactive concentrations of several artificial and natural radionuclides were determined in water and sediment samples collected from various locations in the NW Black Sea in December 1999. For water samples, ⁹⁰Sr and ¹³⁷Cs activity concentrations were of approximately 11 mBq/l and 26.3-41.2 mBq/l, respectively. The concentration of tritium ranged from 7 to 24 T.U. In sediment samples, maximum concentrations of ¹³⁷Cs, ^239+240Pu and ²⁴¹Am were found of 128±6 Bq·kg^-1, 1.8±0.1 Bq·kg^-1 and 0.05±0.04 Bq·kg^-1, respectively. For U and Th radionuclides, the concentrations ranged from 20-80 Bq·kg^-1 and 30-50 Bq·kg^-1, respectively. The results were consistent with those reported in earlier research for the Black Sea. This revised version was published online in July 2006 with corrections to the Cover Date.     

Radioactivity of coal and ashes from Figueira coal power plant in Brazil

Summary The Figueira coal-fired power plant (CFPP) is among the Brazilian CFPP which presents higher uranium concentration. Gamma-ray spectrometry was used to determine ²³⁸U, ²²⁶Ra, ²¹⁰Pb, ²³² Th and ⁴⁰K contents in pulverized coal, furnace bottom ash and fly ash samples. The natural radionuclide concentrations in pulverized coal ranged from 813 to 2609 Bq ^. kg^-1 for U series and from 22 to 40 Bq ^. kg^-1 for ²³² Th. The fly ash fraction gave concentrations ranging from 1442 to 14641 Bq ^. kg^-1, for uranium series. The same enrichment factor was observed for ²³⁸U, ²²⁶Ra and ²³² Th. Only ²¹⁰Pb and stable Pb presented a high enrichment factor for the last stage filter fly ash. The concentration of the uranium series found in the ashes is close to the limit adopted by the Brazilian guideline (CNEN-NN-4.01).²² Therefore, it is advisable to evaluate the environmental impact of the installation.     

Natural radioactivity distribution in geological matrices around Kaiga environment

Summary The activity and absorbed dose rate of the naturally occurring radionuclides, viz. ²³⁸U, ²³² Th and ⁴⁰K were determined in soil and rock samples collected around Kaiga site. The mean activity levels (Kaiga soil) of naturally occurring ²³² Th are comparable with that in worldwide soil, while concentrations of ²³⁸U and ⁴⁰K are lower than those in worldwide soil. The absorbed dose rate in outdoor air ranged 20-58 nGy ^. h^-1 with a mean of 33.3 nGy ^. h^-1, which is below the world average of 60 nGy ^. h^-1. The total effective dose rate in outdoor air for soils ranged 25.6-74.4 mSv ^. y^-1 with a mean of 43.0 mSv ^. y^-1. The estimated dose rate at Kaiga is comparable with that estimated at Kakrapar and Rawatbhata and much less than that estimated at coastal sites of India.     

137Cs in Biota and Sediment Samples from Turkish Coast of the Black Sea, 1997–1998

During the periods of 1997–1998, macroalgae, sea snail, mussel, fish and sediment samples were collected from different stations at Turkish Black Sea coast in order to determine activity levels of ¹³⁷Cs radionuclide. ¹³⁷Cs activity in the tested algae species and in soft parts of mussel and sea snail, were found to be below the lower limit of detection. On the other hand, the ¹³⁷Cs concentration in muscle tissue of the sea snail samples were found from 6±2 to 19±7 Bq·kg^–1 dry weight. The range of the ¹³⁷Cs concentration in anchovy fish muscles were found between 4±2 – 10±5 Bq·kg^–1 dry weight. The ¹³⁷Cs concentration in the whiting fish muscle was found below the lower limit of detection. However, this activity found in shad fish muscle to be 25±10 Bq·kg^–1 dry weight. The concentrationsof the ¹³⁷Cs activity in the sediment samples proved that the eastern region of the Black Sea was affected by Chernobyl at a very high degree compared with the western part. The measured ²³⁸U, ²³²Th and ⁴⁰K concentrations in sediment samples are within the range of the cited values in the previous works at the Turkish Black Sea coast.     

Distribution of <Superscript>137</Superscript>Cs, <Superscript>40</Superscript>K, <Superscript>232</Superscript>Th and <Superscript>238</Superscript>U in coastal marine sediments of Margarita Island,Venezuela

This work presents the results of ¹³⁷Cs, ⁴⁰K, ²³²Th and ²³⁸U concentration (Bq kg⁻¹) values in coastal marine sediments collected from 38 sites along the coastline of the island of Margarita, Venezuela. The purpose was to determine baseline values for these radionuclides in surface marine sediments and to detect if there were any anomalously high concentration values. Only three of the 38 sediments analyzed had measurable values above the detection limit of 0.9 Bq kg⁻¹ for ¹³⁷Cs and the highest only being 1.4 Bq kg⁻¹. While, the concentration (Bq kg⁻¹) ranges for the primordial radionuclides, ⁴⁰K, ²³²Th and ²³⁸U were as follows: 12.2–211.7, <1.5–9.8 and <4.4–20.7, respectively. These concentration ranges for the primordial radionuclides can be considered as baseline values for surface marine sediments for areas that are considered not polluted by man or contaminated by nature. Finally, the concentration range of ¹³⁷Cs can also be employed as baseline values, which only seem to have been the result of the atmospheric testing of nuclear weapons in the past.     

The radioactivity of building materials

Summary Radiation exposure of the population can be increased appreciably by the use of building materials containing above-normal levels of naturally occurring radionuclides of terrestrial origin, as high as 1600 Bq^. kg^-1for ⁴⁰K in granites, 700 Bq^. kg^-1for ²²⁶Ra in phosphogypsum and 360 Bq^. kg^-1for ²³²Th in granites. In a 25-year survey including more than two hundreds of different materials were investigated. Of the materials normally used in the building industry, i.e., red clay bricks, cement of Portland Types I and II, concretes, gravels and sand, contain regular levels of the primordial radionuclides. The adsorbed dose rate in indoor air, in general, does not exceed the dose criterion of 80 nGy^. h^-1or 0.3 mSv^. y^-1for the effective dose. Granites and phosphogypsum are the highly radioactive materials for which the absorbed dose rate in indoor air becomes up to five times higher than the dose criterion. It is recommended to avoid the use of those materials without radioactivity control.     

Determination of radionuclides in the environment using gamma-spectrometry

Summary Seventy nine samples, including soil and rock, were collected from the agrestic region of the State of Pernambuco, Brazil. The activity concentrations of ²³⁸U and ²²⁶Ra in the samples were determined by gamma-spectrometry using an HPGe detector. The concentrations of ²³⁸U were 22 Bq ^. kg^-1 to 22 kBq ^. kg^-1. The concentrations of ²²⁶Ra were 14 Bq ^. kg^-1 to 17 kBq ^. kg^-1. The ²³⁸U/²²⁶Ra ratios in the soil were 0.7 to 3.4 (arithmetic mean 1.7). The radiometric data were evaluated to explain ²³⁸U and ²²⁶Ra migration in the soil and the possible consequences to the environment.     

Measurement of the radioactivity of 238U, 226Ra, 210Pb, 228Th, 232Th, 228Ra, 137Cs and 40K in tea using gamma-spectrometry

The aim of the present work was to determine the concentration of radionuclides in all kinds of tea available at the local Egyptian market. Radioactivity of the nuclides ²³⁸U, ²²⁶Ra, ²¹⁰Pb, ²²⁸Th, ²³²Th, ²²⁶Ra, ¹³⁷Cs and ⁴⁰K were measured in tea by direct γ-ray spectrometry using HPGe detector and their mean values were 16.0±5.3, 3.1±0.7, 34.3±3.4, 3.4±1.2, 3.0±0.6, 3.1±0.8, 0.9±0.2 and 623±25 Bq·kg⁻¹, respectively.