In-situ pre-concentration technique using MnO
2
filter cartridge adapted for radium isotopes measurement in seawater. Natural variability was observed and data subjected to statistical analysis. ...Seawater and sediment concentration was observed lognormal and evaluated geometric mean for
226
Ra was 2.9 Bqm
−3
and 1.7 Bqm
−3
and
228
Ra was 5.8 Bqm
−3
and 4.6 Bqm
−3
in seawater along west and east coast respectively. For sediment
226
Ra GM was 12.5 Bqkg
−1
and 30.0 Bqkg
−1
and
228
Ra was 21.7 Bqkg
−1
and 62.0 Bqkg
−1
along west and east coast respectively. Estimated environmental increment could be used as screening levels for assessing impact on the environment.
Assessment of potential impacts on the environment around the nuclear facilities requires precise estimation of prevailing background concentration and statistical inference of the measurement data. ...The current study was focused to understand the statistical variation associated with data generated for
137
Cs concentration in sea water and sediment for the west and east coat of India. The distribution followed was found to be lognormal and based on geometric mean and geometric standard deviation of the
137
Cs concentrations data, a screening level in terms of Environmental Increment factor has been evaluated which can form basis for future impact assessment.
•Layered chalcogenide with CdI2 crystal structure prepared by hydrothermal route.•Exploration of the possibilities for radionuclides’ uptake using layered chalcogenide.•Proposing ‘topotactic ionic ...substitution’ as major uptake mechanism.
Ensuring environmental protection in and around nuclear facilities is a matter of deep concern. Toward this, layered chalcogenide with CdI2 crystal structure has been prepared. Structural characterizations of layered chalcogenide suggest ‘topotactic ionic substitution’ as the dominant mechanism behind uptake of different cations within its lattice structure. An equilibration time of 45min and volume to mass ratio of 30:1 are found to absorb 233U, 239Pu, 106Ru, 85+89Sr, 137Cs and 241Am radionuclides to the maximum extents.
The uptake of naturally occurring uranium, thorium, radium and potassium by wheat plant from two morphologically different soils of India was studied under natural field conditions. The soil to wheat ...grain transfer factors (TF) were calculated and observed to be in the range of 4.0
×
10
−4 to 2.1
×
10
−3 for
238U, 6.0
×
10
−3 to 2.4
×
10
−2 for
232Th, 9.0
×
10
−3 to 1.6
×
10
−2 for
226Ra and 0.14–3.1 for
40K. Observed ratios (OR) of radionuclides with respect to calcium have been calculated to explain nearly comparable TF values in spite of differences in soil concentration of the different fields. They also give an idea about the discrimination exhibited by the plant in uptake of essential and nonessential elements. The availability of calcium and potassium in soil for uptake affects the uranium, thorium and radium content of the plant. The other soil factors such as illite clays of alluvial soil which trap potassium in its crystal lattice and phosphates which form insoluble compounds with thorium are seen to reduce their availability to plants. A major percentage (54–75%) of total
238U,
232Th and
226Ra activity in the plant is concentrated in the roots and only about 1–2% was distributed in the grains, whereas about 57% of
40K activity accumulated in the shoots and 16% in the grains. The intake of radionuclides by consumption of wheat grains from the fields studied contributes a small fraction to the total annual ingestion dose received by man due to naturally existing radioactivity in the environment.
A simple wavelet transformation based pre-processing method is employed to minimize the duration of counting for gamma spectrometric measurements of samples from environmental matrices. Among the ...various forms of analyzing wavelets, a suitable one is chosen for this purpose. Measurements with 55 different counting durations were subjected to the wavelet based processing and results were compared with long duration counting time measurements of
40
K,
137
Cs, radionuclide from
238
U series (
214
Bi,
214
Pb) and
232
Th series (
228
Ac,
212
Bi,
212
Pb,
208
Tl). It is observed that with a proper choice of the wavelet function a tenfold reduction in counting duration can be achieved with errors <5 %.
A wavelet transform based denoising methodology has been applied to detect the presence of any discernable trend in 137Cs and 90Sr activity levels in bore-hole water samples collected four times a ...year over a period of eight years, from 2002 to 2009, in the vicinity of typical nuclear facilities inside the restricted access zones. The conventional non-parametric methods viz., Mann–Kendall and Spearman rho, along with linear regression when applied for detecting the linear trend in the time series data do not yield results conclusive for trend detection with a confidence of 95% for most of the samples. The stationary wavelet based hard thresholding data pruning method with Haar as the analyzing wavelet was applied to remove the noise present in the same data. Results indicate that confidence interval of the established trend has significantly improved after pre-processing to more than 98% compared to the conventional non-parametric methods when applied to direct measurements.
► Environmental trend analysis with wavelet pre-processing was carried out. ► Removal of local fluctuations to obtain the trend in a time series with various mother wavelets. ► Theoretical validation of the methodology with model outputs. ► Efficient detection of trend for 137Cs, 90Sr in bore-hole water samples improves the associated confidence interval to more than 98%. ► Wavelet based pre-processing reduces the indecisive nature of the detected trend.
Shallow land burial is routinely used for the disposal of low-level radioactive waste. Natural processes causing leaching of radionuclides can lead to contamination of surrounding ground water and ...soil by the radionuclides. The comparative leachability of radionuclides U sub((nat)), super(226)Ra, super(228)Ra and Th sub((nat)) from the soil of a radioactive waste disposal site, by ground water was evaluated. The probability of leaching was obtained in the following order Ra ( approximately 77%) > U ( approximately 40%) > Th ( approximately 20%). Observed ratios (OR) were calculated to correlate leachability of radionuclides to that of major cations Ca super(2+) and Mg super(2+). The leaching of the radionuclides was seen to be dependent on Ca super(2+) and SO sub(4) super(2-) leached from the soil. This study provides sitespecific leachability of radionuclides, that can be used as indicator of the tendency for migration or retention in soil. It can play an important role during an unforeseen accident like breach of containment at the waste disposal site leading to contamination of soil and ground water and causing hazard to public via drinking water route.
Assessment of potential impacts on the environment around the nuclear facilities requires precise estimation of prevailing background concentration and statistical inference of the measurement data. ...The current study was focused to understand the statistical variation associated with data generated for .sup.137Cs concentration in sea water and sediment for the west and east coat of India. The distribution followed was found to be lognormal and based on geometric mean and geometric standard deviation of the .sup.137Cs concentrations data, a screening level in terms of Environmental Increment factor has been evaluated which can form basis for future impact assessment.
Uranium determination in environmental samples is faced with problems due to presence of iron and other major elements. Iron is also used many a times for pre-concentration of uranium and actinides. ...Separation of milligram quantity of Fe from microgram quantity of uranium becomes essential during the estimation step. A simple two step procedure has been standardized for separating uranium and iron using anion exchange in 0.025 M H
2
SO
4
. Quantitative recovery of uranium was obtained as well as good separation from iron. This method was applied for estimation of uranium in water samples.
