Tracing in hydrogeology of underground watercourses using DNA tracers

Abstract

Underground water sources and their movement in various rocks, including karsts, are of considerable interest for many reasons, among which human economic activity plays a significant role. Various compounds are used to trace underground waters – stable and radioactive isotopes, microorganisms and bacteriophages, solid particles as lycopodium spores, chlorides and bromides, other ions, as well as fluorescent dyes. Relatively recently, DNA molecules have been used for this purpose, which can be detected with high sensitivity using a polymerase chain reaction. The commonly used number of DNA tracers is 1015 - 1016 molecules, which, despite significant dilution by water flows, ensures their subsequent detection. In addition to the high sensitivity of such analyses, other advantages of DNA molecules for tracing watercourses are their harmlessness for ecology, relative cheapness. In view of the possible destruction of DNA molecules in an aqueous medium and their sorption on various rocks, it is proposed to use encapsulated molecules, the shells of which are polylactic acid, silica, alginate and other compounds. An experiment on tracing the watercourse of the Tyutyulena stream from the ponor at the Kosh cave to the Traval griffin is predicted, indicating that in this case, taking into account the water flow, only about 1012 DNA molecules will be enough.