ИСТИНА

In the samples of ground water, an active microbial community capable of using nitrate, pertechnetate ions for cell respiration was found. One of the main step of Tc reduction is nitrate reduction. The results of computer geochemical modeling have shown that the immobilization of technetium in the formation occurs mainly in the form of a tetravalent oxide and in a mixture with a biogenic sulphide. while biogenic sulfide ions can play the role of an antioxidant buffer in the event of ingress of new portions of the oxidant into the system. It is important to note that Tc reduction occurs only after nitrate consumption and Eh reduction to anaerobic zone. Thus microbial roles in Tc immobilization are: biogeochemical - Eh reduction due to oxidizer consumption (oxygen, nitrate etc); - mineralization by biogenic sulphide interaction and biochemical – dissimilatory Tc reduction due to oxidoreductaze enzymes.