Yes.
In my country, truly selenium-rich strata are limited to a few shale formations from specific geological periods, and these are often aquitards, making it difficult to find large reserves of selenium-rich water.
Furthermore, selenium-rich strata often also accumulate other harmful heavy metals. Even if a source meets the standards for natural selenium-rich mineral water (10-50 ug/L of selenium), the levels of harmful elements often exceed the limits. Therefore, natural selenium-type mineral water sources are extremely rare, and their development and production have not yet reached a large scale. Finding natural selenium-rich mineral water resources with high flow rates, stable selenium content, and low levels of other harmful elements is the key technology for the development of selenium-rich mineral water in my country.
