Essential and toxic elements in clays for pharmaceutical and cosmetic use.

Essential and toxic elements (Al, Si, P, S, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, As, Br, Rb, Sr, Ba, Cd, Ce, Nd, Pb, U, Th, and La) were determined by energy-dispersive polarized x-ray fluorescence spectrometry (EDPXRF) in 15 samples of clay materials for pharmaceutical and cosmetic use. The investigated samples were grouped according to their mineralogical composition determined by x-ray powder diffraction (XRPD). Samples consisting of smectites showed the lowest content of K, Zn, La, Ce, Nd, Pb, Ti, and Th and highest quantity of Sr, Br, and U. The sample containing smectite and kaolinite displayed the lowest content of Ca, Fe, Mn, Cu, Ni, and Sr and highest amount of Al, Si, Ba, Zn, As, La, Ce, Pb, and Th. Samples composed of illite demonstrated minimal amounts of Br and maximal content of K, Rb, Ti, and Fe. In all samples analyzed, Cd and Hg levels were below 2 mg/kg.