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Sea coasts ecology




Ecology             

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       Sea of Azov
       Kerchenskiy proliv
       The Black sea

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"Black" sands

Black      Black sands are dangerous natural phenomena on some sea coasts. The black sands result from an accumulation of the minerals contained natural radionuclides (thorium, uranium and their decay products) and look like black areas on the sand beaches. In these places, the radioactivity can be higher in tens and hundreds times in comparison with natural background.
     Radioactive sands have been formed as a result of natural geological processes. The main radioactive elements in these sands are thorium-232 and its decay products irradiating alfa, beta and gamma-radiations.
     The intensity of the gamma-radiation in the places of black sand accumulations could be 50-300 mkR/hour, but in some places it could reach as high as 900-1000 mkR/hour. For comparison, the natural background in Moscow is 16-25 mkR/hour, which is regarded as normal. Figures shown earlier relates only to outer radiation, however, in the places of black sands accumulation there is a possibility of inner radiation of organism.
    It should be noted that inner radiation can be a lot higher than outer one, due to the fact that during inner radiation, alfa-emissions become considerably more significant. It is well known that biological effectiveness of alfa-radiation is much higher than beta and gamma-ones.
    In the case of black sands increasing danger of inner radiation can be explained with two components:
     1) Radioactive gases (radon-218 and radon-220) and their decay products.
     2) Dusty particles of black sands, which have been rising in the air by strong winds.
     There are often very strong winds on the sea coasts, which can turn to dusty storm and raise a great amount of sands in the air. These sandy clouds can influence on the radiation situation not only on the nearest coasts, but also in the other areas.
     The absorption of radioactive dusty particles and radioactive gases inside organism can result in oncological diseases. It is known that hardly dissolvable thorium compounds can cause cancerous actions. Even more dangerous are combinative actions of thorium and uranium. There is a big possibility, that high level of oncological sicknesses among coast habitants, especially among children, can be related with existence of black sands.
    There are the observations showing that not high, but rather repeated radiation can increase a possibility of the oncological sicknesses among children.
    Moreover, there seems to be combinative actions of radioactive and ultraviolet radiations.
     Black sands on the sea coasts have been discovered also in India, Brazil and Sri-Lanka. In Russia and Ukraine they can be met on the Sea of Azov and the Black Sea and the uniqueness of these accumulations is due to three factors acting in the same time: existence of black sands, the high density of population and resting people and dry strong winds.
     An absence of one of these factors solves completely or partially the problem, but namely three factors acting simultaneously create significantly dangerous and unique situation.
     It is wrongly believed that even the radioactive danger is high; we can do nothing with it, because this is a natural phenomenon and has a geological scale. Therefore, the wise tactics of silence and calming are chosen. Meanwhile, this is not the truth and there are rather simple and effective methods of fighting with this dangerous phenomenon. These methods, even if they could not completely remove the harm, could considerably decrease it. The existence of black sands can not be a reason for closing the whole coast for resting, because black sands are concentrated in the definite places with characteristic shore line, but it is obvious that these places should be taken under strict control with performing of defensive actions. Meanwhile, the simplest and the cheapest way is to avoid the places with black sand accumulations.


Black sand geography

Black     The radioactive sands are located on the sandy beaches as spots or strips of black color. They have different areas and spread from tens cm2 to hundreds m2.
     They can be easily distinguished from other dark objects on the shore by their metallic flashing and high density.
     On the surface of black sand area, the radiation level could be some hundreds of mkR/hour, depending on layer thickness and the level of radionuclide enrichment, but some meters from the area, the radiation level of ordinary sand is normal (15-20 mkR/hour).
     On this web-site you can find an unique data base of places of black sand accumulation on the Black Sea and the Sea of Azov coasts, and many other information, which could be useful for people going to rest here (beaches and water conditions, traffic convenience, hotels and so on).



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