Environment Of Kaiga Research Articles

Transfer coefficient of 137Cs from feed to cow milk in tropical region Kaiga, India

In the transport model for the prediction of the concentration of (137)Cs in milk, the transfer coefficient from feed to milk, F(m), is an important parameter. Site-specific transfer coefficient from feed to cow's milk, for (137)Cs in the Kaiga environment, a nuclear power station site in India, determined over a period of 10 y is presented in this paper. The value is determined from (137)Cs concentration in milk and grass samples of the Kaiga region and the result ranged from 6.43E-03 to 1.09E-02 d l(-1) with a geometric mean value of 8.0E-03 d l(-1). The result is compared with that for (40)K, determined concurrently at the same region and ranged from 3.06E-03 to 3.48E-03 d l(-1) with a geometric mean value of 3.26E-03 d l(-1). This parameter is quite useful in decision-making for implementing countermeasures during a large area contamination with (137)Cs in tropical areas like Kaiga.

Natural radioactivity distribution in geological matrices around Kaiga environment

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.

226Ra, 40K and 7Be activity concentrations in plants in the environment of Kaiga, India

Leaves, stem and bark samples from several plant species were collected from tropical forest of Kaiga, in the west coast of India where two nuclear power reactors of 220 MW each have just been commissioned and another two are under construction, and analysed for their 226Ra, 40K and 7Be concentrations. The activities of 226Ra and 40K in plants were found to vary in the range BDL–13.2 and 12.0–797.3 Bq kg −1, respectively. Plants show significant 7Be activity in leaves, the activity varies in 72.5–1060.8 Bq kg -1. Stem and bark of plants show higher levels of 226Ra and 40K when compared to leaves. Soil-to-plant transfer factor for 226Ra and 40K were found to vary in the range BDL–0.37 and 0.09–5.61, respectively for different plants. The concentration of 226Ra and 40K in leaves depends on the age of the leaves.

Radium-226, 232Th, and 40K distribution in the environment of Kaiga of south west coast of India.

Systematic studies on gamma radiation level and the distribution of natural radionuclides were carried out under a pre-operational survey for the establishment of baseline data on background radiation level and the distribution of radio-nuclides in the environment of Kaiga, in the south west coast of India, where a nuclear power reactor of 235 MWe has just been commissioned. The external gamma absorbed dose rates prevailing in the region were measured using a portable plastic scintillometer. Soil samples from 18 stations were collected from depth intervals of 0-5, 5-10, and 10-25 cm and analyzed for their 226Ra, 232Th, and 40K activity concentrations by gamma spectrometry employing a 90 cc PGT HpGe detector coupled to an EG&G ORTEC 8K multichannel analyzer. The activity of 226Ra was found to vary between 15.5-61.2 Bq kg(-1) with a mean value of 31.3 Bq kg(-1), that of 232Th varies between 11.4-41.9 Bq kg(-1) with a mean value of 27.5 Bq kg(-1) and of 40K between 78.3-254.8 Bq kg(-1) with a mean value of 159.9 Bq kg(-1) in 0-5 cm soil profiles of the region. The contributions of 238U, 232Th, and 40K to the total gamma absorbed dose rate were 39.9%, 40.7%, and 16.0%, respectively. The gamma absorbed dose rate in air estimated using the results of activity concentration of 226Ra, 232Th, and 40K are found to compare well with that of the direct measurement. The results of the study were compared with the literature values reported for other environs of the country as well as the world, and conclusions are drawn.

Base line radioactivity levels in Kaiga site soil and its migration to biosphere

The effects of variation in different parameters on the environmental distribution of base line 137Cs and 40K activities in Kaiga environment and their migration into biosphere are discussed. Transfer factors of these radionuclides from soil to different parts of commonly available plants in this region were estimated. Base line radioactivity levels in soil at Kaiga were higher as compared to pre-operational values reported from other power station sites in India and were mainly attributed to the very high precipitation rate prevailing in this area. Also, this area being an undisturbed forest land, fallout activities are re-circulated to the soil by the decay of parts of trees.40K and 137Cs activity levels in leaves of shallow rooted plants were found to be higher as compared to that in deep rooted trees. Transfer factors of soil to plant parts revealed that there is no major bio-accumulation of 137Cs in any parts of Colocassia esculenta (L.) and Chromolaena odorata (L.) King & Robinson. Comparison of 40K/137Cs ratio between soil and different parts of these plants has revealed that uptake of K is relatively more efficient as compared to that of Cs, presumably because of the faster kinetics of K due to its larger atom inventory in the soil.

Distribution and enrichment of [formula omitted] in the environment of Kaiga in South India

Several soil and vegetation samples from the environment of Kaiga nuclear power plant site in the south western region of India were analysed for 210 Po . The vertical profile, particle-size distribution, seasonal variation and the dry deposition rate of 210 Po were measured employing the chemical method and α – counting technique. 210 Po activity in soil varies from 17.1 to 228.2 Bq kg −1 with a mean value of 83.3 Bq kg −1. The activity of 210 Po is higher in the surface soil (0–5 cm) and decreases as depth increases to 20 cm and remains nearly constant thereafter. The activity concentration is almost uniform in the grain sizes of 350–177 μm and below 177 μm. Pterobryopsis tumida (Hook.) Dix, a plant of the moss family, shows a very high level of 210 Po activity — 2724±13 Bq kg −1. Seasonal variation studies show elevated levels of 210 Po in vegetation during winter. The annual dry deposition rate of 210 Po was 53.4 Bq m −2 yr −1.

Caesium-137 concentration in Kaiga environment

Measurement of radioactivity levels in various environmental matrices at the Kaiga nuclear power plant and the surrounding environs has been carried out on a routine basis to establish the baseline background radiation level prevailing in the region. Measurement of the concentration of Cs-137 in environmental matrices is necessary to estimate the amount of fallout of this radionuclide in the region and to assess the long term impact of the nuclear power plant on the environment.

96/05472 Bioindicators in the tropical forest of Kaiga environment

96/05472 Bioindicators in the tropical forest of Kaiga environment

Atmospheric radon levels and its emanation rate in the environment of Kaiga

A systematic study of atmospheric radon levels and of radon emanation rates was conducted in the environment of Kaiga on the south-west coast of India where the installation of nuclear power reactors is in progress. 222Rn emanation rates were estimated employing the accumulating chamber method and were found to vary from 5.6 to 62.9 mBq m −2 s −1 with a geometric mean of 30.0 mBq m −2 s −1. The atmospheric concentrations were estimated using CR-39 solid state nuclear track detectors (SSNTDs) and found to vary from 4.7 to 27.9 Bq m −3 with a geometric mean of 13.4 Bq m −3. The results show a strong correlation between emanation rate and atmospheric concentration while showing a poor correlation between 226Ra concentration in surface soil and atmospheric concentration of 222Rn. The results are also compared and discussed in the light of relevant literature reported for other environments.

Bioindicators in the tropical forest of Kaiga environment

Investigations on the natural and artificial fallout radionuclides 210Po and 137Cs and the primordial radionuclide 40K in the prominent tree species of Western Ghat tropical forests near Kaiga have been carried out as a part of baseline background radiation studies in the environment of Kaiga where nuclear power reactors are being installed. The prominent tree species of the region Tectona grandis L.f. and Terminalia paniculata Roth., and the commonly available epiphytic plant species Pterobryopsis tumida (Hook.) Dix. and Cymbidium aliofolium (Lo) Swartz. were chosen and concentrations of 40K, 210Po and 137Cs were measured employing well-established nuclear techniques. The different parts of Cumbidium aloifolium (Lo) Swartz. such as leaves, stem, etc. were analysed to understand the absorption mechanism of fallout radionuclides. From a careful analysis of the results, the epiphytic plant species are identified as bioindicators to monitor fallout radionuclides.