COMPARISON OF CONCENTRATIONS OF TOXIC ELEMENTS IN THE HAIR OF FIRST-YEAR STUDENTS OF RUDN UNIVERSITY FROM DIFFERENT REGIONS OF THE WORLD: A CROSS-SECTIONAL STUDY Article Galchenko A.V., Sidorova E.I., Sherstneva A.A., Skalny A.A., Lobanova J.N. Environmental Science and Pollution Research. Springer Science + Business Media. 2021.