about 23% and with resolution 0.66 kev at energy of radiation of radionuclide
1.46 Mev. The analysis of obtained gamma-spectra was carried out with using of
the Analyzer MCA, S100, System 100. The data obtained were statistically treated
according to commonly accepted techniques (Polikarpov et al. 2008).
In cruise 2013, as mentioned above, the original method of
137 Cs determination
from relatively small volumes of water was applied, which allowed for the first time
after the ChNPP accident to get full information about vertical distribution of
137 Cs
in the deep-layers basin of the Black Sea.
The quality control of the analytical methods and the reliability of the results for
90 Sr and for radionuclides of
137 Cs and
239, 240 Pu were supported from the constant
participation in international intercalibrations during 1990–2004 under the aegis of
the IAEA (Vienna, Austria), (Polikarpov et al. 2008).
Adjustment of the periods of the exchange water in the oxidation and reduction
zones of the Black Sea was conducted using a model of the large-scale radioisotopic, salt and water balance of the sea (Stokozov 2004). For parameterization of this
model the data on changes in the profiles of the vertical distribution of
137 Cs and
90
Sr in the water during the post-Chernobyl period were used. The components of the
water balance, including river flow, evaporation, precipitation, and water exchange
through the Black Sea straits, were determined by the results of long-term meteorological observations (Voitsekhovitch et al. 1998), and averaged profiles of the
vertical distribution of water salinity were evaluated on numerous data of hydrological surveys.
It was found, that the dynamics of the concentrations of the after-accident
radionuclides in the Black Sea ecosystem are described adequately by an exponential function. Estimation of the forecast of time for
90 Sr and
137 Cs concentrations
decrease in the components of the Black Sea ecosystems to the before-accident
levels were fulfilled by method of an extrapolation of the approximating line of the
exponential function (Mirzoyeva 2008; Mirzoyeva et al. 2013).
17.3
90
Sr and
137
Cs in the Black Sea Ecosystems. Results
17.3.1 Sea Water
Chronological trends of the horizontal distribution of the average concentrations of
90 Sr and
137 Cs in the surface layer of sea water of the North-Western part and the
region of the Crimean coast of the Black Sea are summarized and presented in
Table 17.2 (IAEA 2004; Database ORChB IMBR 2006; Polikarpov et al. 2008.;
Gulin et al., 2013, Tereschenko et al. 2014).
Comparative distribution of modern concentrations of
90 Sr and
137 Cs in the
surface layer of water of the Black Sea in 2011 and 2014–2016 years (2 years
before and during the period after the termination of the water supply from the
North-Crimean canal (NCC) on the territory of Crimea, respectively) is shown in
280
N.Y. Mirzoyeva et al.
1.46 Mev. The analysis of obtained gamma-spectra was carried out with using of
the Analyzer MCA, S100, System 100. The data obtained were statistically treated
according to commonly accepted techniques (Polikarpov et al. 2008).
In cruise 2013, as mentioned above, the original method of
137 Cs determination
from relatively small volumes of water was applied, which allowed for the first time
after the ChNPP accident to get full information about vertical distribution of
137 Cs
in the deep-layers basin of the Black Sea.
The quality control of the analytical methods and the reliability of the results for
90 Sr and for radionuclides of
137 Cs and
239, 240 Pu were supported from the constant
participation in international intercalibrations during 1990–2004 under the aegis of
the IAEA (Vienna, Austria), (Polikarpov et al. 2008).
Adjustment of the periods of the exchange water in the oxidation and reduction
zones of the Black Sea was conducted using a model of the large-scale radioisotopic, salt and water balance of the sea (Stokozov 2004). For parameterization of this
model the data on changes in the profiles of the vertical distribution of
137 Cs and
90
Sr in the water during the post-Chernobyl period were used. The components of the
water balance, including river flow, evaporation, precipitation, and water exchange
through the Black Sea straits, were determined by the results of long-term meteorological observations (Voitsekhovitch et al. 1998), and averaged profiles of the
vertical distribution of water salinity were evaluated on numerous data of hydrological surveys.
It was found, that the dynamics of the concentrations of the after-accident
radionuclides in the Black Sea ecosystem are described adequately by an exponential function. Estimation of the forecast of time for
90 Sr and
137 Cs concentrations
decrease in the components of the Black Sea ecosystems to the before-accident
levels were fulfilled by method of an extrapolation of the approximating line of the
exponential function (Mirzoyeva 2008; Mirzoyeva et al. 2013).
17.3
90
Sr and
137
Cs in the Black Sea Ecosystems. Results
17.3.1 Sea Water
Chronological trends of the horizontal distribution of the average concentrations of
90 Sr and
137 Cs in the surface layer of sea water of the North-Western part and the
region of the Crimean coast of the Black Sea are summarized and presented in
Table 17.2 (IAEA 2004; Database ORChB IMBR 2006; Polikarpov et al. 2008.;
Gulin et al., 2013, Tereschenko et al. 2014).
Comparative distribution of modern concentrations of
90 Sr and
137 Cs in the
surface layer of water of the Black Sea in 2011 and 2014–2016 years (2 years
before and during the period after the termination of the water supply from the
North-Crimean canal (NCC) on the territory of Crimea, respectively) is shown in
280
N.Y. Mirzoyeva et al.