REE migration in the waters of the tungsten deposits technogenesis zone of Eastern Transbaikalia

Abstract

Introduction: The relevance of the work is determined by the need for a solution to the problem of preserving the quality of water resources under the influence of mining. The goal of the study was the investigation of the behaviour of rare earth elements (lanthanides) and determining the forms of their presence in the waters of tungsten deposits in Eastern Transbaikalia. The objects of research were nat ural and technogenically transformed waters formed within the territories of the Bukukinskoye, Belukhinskoye, Antonovogorskoye, Dedovogorskoye, Bom-Gorkhonskoye, and Spokoyninskoye deposits impaired by industrial development. Methodology: A total of 34 water samples were taken, the concentrations of water anions were determined using conventional methods, cations and metals were determined using the atomic absorption method and inductively coupled plasma mass spectrometry. The determination of the forms of migration of rare earth elements was carried out by the calculation method using the HydroGeo32 software package. Results and discussion: The highest contents of rare earth elements (total contents up to 1.1–3.6 mg/L) were recorded in the acidic SO4 Mg-Ca waters of the Bom-Gorkhonskoye, Bukukinskoye, Antonovogorskoye, and Belukhinskoye deposits. The waters of the Spokoyninskoye and Dedovogorskoye deposits were neutral and slightly alkaline HCO3 Mg–Ca with contents of total lanthanides up to 0.6–1.7 μg/l. Fractionation of rare-earth elements of two differently directed types has been revealed. Positive and negative correlations between the contents of rare earth elements and the content of F-, SO42-, Al, Fe, Mn were identified. Three types of hydrogeochemical media have been identified. These media were different, among other things, by predominant forms of migration: in acidic and weakly acidic waters with Eh > 350 mV, migration occurred mainly in the form of simple cations and sulphate complexes; in slightly acidic and near-neutral waters with Eh 200-350 mV migration occurred in the form of simple cations, sulphate, fluoride, and carbonate ions; in near-neutral and slightly alkaline waters with Eh < 200 mV migration occurred in the form of simple cations and fluoride and carbonate complexes. Conclusions: In the waters of six tungsten deposits in Eastern Transbaikalia, simple cationic, sulphate, fluoride, and carbonate inorganic forms of the existence of rare earth elements were identified. The obtained results can be used to develop measures for the prevention of water pollution and to carry out water purification.