“…The enrichment factor (EF) is an effective normalization tool widely used to separate PTEs of natural variability from element fractions associated with anthropogenic activities. ,, In this study, the EF to Earth’s crustal average was used to evaluate the degree of PTEs in the bentonite samples. EFs for Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Zr, and Pb in the bentonite samples in all sampling areas were calculated as follows: , EF = false( true C PTE C R e normalf false) Bentonite false( true C PTE C R e normalf false) Earth ′ normals 0.25em crust where C PTE and C Ref are the concentration of PTEs and reference element in the bentonite sample and Earth’s crust, respectively. When the relevant literature is examined, it is seen that elements such as Al, Mn, Fe, Ca, Zr, Sc, Sr, and Ti are used as references based on different reasons in the calculation of the EF. ,− In this study, Sr was used as a reference element due to its low occurrence.…”