16.4 Conclusion
The studies revealed radiological regularities of the Pu behavior in the Black Sea
ecosystem. Quantitative parameters of biogeochemical processes of plutonium
migration: Concentration factor against
239þ240 Pu by biota and abiotic components,
factor of radiocapacity of bottom sediment, the average annual fluxes of
239þ240 Pu
in different parts of the sea, the effective half–life of
239þ240 Pu in the Black Sea
surface waters, the levels of its concentration activity in ecosystem components.
It was noted an increase in the ability of the Black Sea surface water to self–
purification, compared to other seas, particularly the Mediterranean Sea. The
revealed features of redistribution of
239þ240 Pu in the Black Sea are connected
with both conditions, formed in the sea, in particular, the presence of a reducing
hydrogen sulfide zone in the sea as well as the properties of plutonium, which
determined the silty bottom sediments as the main long–term depot of plutonium.
The obtained results allowed characterizing the role of shelf areas and the deep zone
in plutonium migration and deposition.
It was recommended the sea algae, as a link in the food chain with the maximum
accumulative capacity in respect of plutonium among biotic components and
defined the critical habitat – silty bottom sediment as the main place of deposit of
the prevailing part of the plutonium incoming into the sea, curried out a quantitative
assessment of pedotropic type of biogeochemical behavior of plutonium in the
Black Sea ecosystems.
Thus, the study of the radoiecological regularities and quantitative characteristics of the redistribution of
239þ240 Pu in the Black Sea make it possible to form a
scientific basis for the characteristics of plutonium redistribution trends in the Black
Sea ecosystem in different spatial and temporal scales, to evaluate and predict the
radioecological state of waters at different possible concentration activities of the
Black Sea waters against plutonium radionuclides using quantitative parameters of
biogeochemical migration of plutonium in the Black Sea ecosystem.
Thus, the expected ecological effect of the radiation was determined by the level
of
239,240 Pu concentration activity in sea water and its connection with the value of
accumulative ability of marine species and its radiosensitivity. In after ChNPP
accident period the levels of dose rates were formed from plutonium did not exceed
the levels typical for the “Well-being zone”. Therefore, the contemporary levels of
plutonium concentration in the Black Sea, have no a noticeable negative effect on
the Black Sea hydrobionts. The Black Sea hydrobionts are exposed to the action of
the concentrations of different contaminators in the water environment, and they
also have an increased accumulative ability. They are capable of accumulating
contaminators (in particular
239,240 Pu) to levels exceeding tens and tens thousands
times their concentration activity in the water, and thus the risk is increased many
times of the negative influence of radioactive contamination on biological systems
and objects. In connection with this, the radioecological monitoring investigations
must include the determinations of the radionuclides concentration activity, both in
the sea water and bottom sediment and in the indicated species of hydrobionts too.
16 Levels of Activity Concentration, Migration and Dose Rates on Biota from. . .
269
The studies revealed radiological regularities of the Pu behavior in the Black Sea
ecosystem. Quantitative parameters of biogeochemical processes of plutonium
migration: Concentration factor against
239þ240 Pu by biota and abiotic components,
factor of radiocapacity of bottom sediment, the average annual fluxes of
239þ240 Pu
in different parts of the sea, the effective half–life of
239þ240 Pu in the Black Sea
surface waters, the levels of its concentration activity in ecosystem components.
It was noted an increase in the ability of the Black Sea surface water to self–
purification, compared to other seas, particularly the Mediterranean Sea. The
revealed features of redistribution of
239þ240 Pu in the Black Sea are connected
with both conditions, formed in the sea, in particular, the presence of a reducing
hydrogen sulfide zone in the sea as well as the properties of plutonium, which
determined the silty bottom sediments as the main long–term depot of plutonium.
The obtained results allowed characterizing the role of shelf areas and the deep zone
in plutonium migration and deposition.
It was recommended the sea algae, as a link in the food chain with the maximum
accumulative capacity in respect of plutonium among biotic components and
defined the critical habitat – silty bottom sediment as the main place of deposit of
the prevailing part of the plutonium incoming into the sea, curried out a quantitative
assessment of pedotropic type of biogeochemical behavior of plutonium in the
Black Sea ecosystems.
Thus, the study of the radoiecological regularities and quantitative characteristics of the redistribution of
239þ240 Pu in the Black Sea make it possible to form a
scientific basis for the characteristics of plutonium redistribution trends in the Black
Sea ecosystem in different spatial and temporal scales, to evaluate and predict the
radioecological state of waters at different possible concentration activities of the
Black Sea waters against plutonium radionuclides using quantitative parameters of
biogeochemical migration of plutonium in the Black Sea ecosystem.
Thus, the expected ecological effect of the radiation was determined by the level
of
239,240 Pu concentration activity in sea water and its connection with the value of
accumulative ability of marine species and its radiosensitivity. In after ChNPP
accident period the levels of dose rates were formed from plutonium did not exceed
the levels typical for the “Well-being zone”. Therefore, the contemporary levels of
plutonium concentration in the Black Sea, have no a noticeable negative effect on
the Black Sea hydrobionts. The Black Sea hydrobionts are exposed to the action of
the concentrations of different contaminators in the water environment, and they
also have an increased accumulative ability. They are capable of accumulating
contaminators (in particular
239,240 Pu) to levels exceeding tens and tens thousands
times their concentration activity in the water, and thus the risk is increased many
times of the negative influence of radioactive contamination on biological systems
and objects. In connection with this, the radioecological monitoring investigations
must include the determinations of the radionuclides concentration activity, both in
the sea water and bottom sediment and in the indicated species of hydrobionts too.
16 Levels of Activity Concentration, Migration and Dose Rates on Biota from. . .
269