Geochemical behavior of Mo and W in the CO2-rich mineral waters occurring in the East Elbrus area. Issue 1 (October 2021) - Chelnokov, G A
Abstract: Molybdenum and tungsten concentrations in cold CO2 -rich mineral groundwaters of east Elbrus area lie in two ranges: 0.01-0.43 ppb and 0.01-410 ppb. The temperature of the water varies from 7.9 to 17.6 °C. Mo concentrations have irregular behaviour with temperature and do not demonstrate a significant correlation with any parameters. Tungsten concentrations are strongly and positively correlated only with As, indicating either common sources or common processes controlling their grades. The highest W concentrations are exclusively associated with Na–HCO3 –Cl water types, with a circum-neutral condition (6<pH<7) and lower Eh (-60-+45 mV). The dominant species of Mo and W in mineral waters of eastern Elbrus are molybdate ion (MoO4 ), and [W7 O24 ] 6- polyanion. Based on the risk assessment results, for two potential contaminants (Mo and W), the concentration level of W exceeded the environmental quality standard, which suggests a severe to moderate ecological risk and, therefore, needs to be considered as the priority pollutant for the studied area.