Microbial ecological function in migration of radionuclides in groundwater

This chapter shows findings obtained from a microbial ecological study carried out on groundwater contaminated with radionuclides and nitrate in the area of Lake Karachai in southern Ural. This study was conducted to answer the questions raised from previous studies at the same site on the difference in migration patterns between strontium-90 and nitrate, a co-contaminant regarded as an indicator of the motion of radionuclides. The results suggest that denitrification occurred in some part of the given groundwater, and this caused a decrease in nitrate concentration at that site. Furthermore, microbial denitrification activity leads to a decrease in redox potential. Thus, microbial denitrifying activity may affect the behavior of radionuclide in differentiation of their chemical species in valent status. Ecological understanding of microbes, in addition to the information of microbial direct function in adsorbing and absorbing radionuclides, and modifying the chemical species of radionuclides through direct reaction with elements, may give us a further and more accurate picture of the role of existing microbes in contaminated groundwater. This may allow a greater move forward in understanding the migration of radionuclides in groundwater. Chapters 2 , 3 , 6 , 7 , and 8 also discuss this study site. Therefore, a concise general description is included in this chapter.