Trace elements in the clinoptilolite tuffs from four Bulgarian deposits, Eastern Rhodopes

In this study, we are focusing on the presence and contents of the rare earth and trace elements in the clinoptilolite-rich tuffs of the four large zeolite deposits Beli Plast, Golobradovo, Most and Beliya Bair (Eastern Rhodopes, Bulgaria). The chemical properties of the tuffs were studied with regard to be used in eco-toxicological experiments as sorbents for detoxification of the experimental animals. The clinoptilolite tuffs are relatively depleted in Sc, V, Cr, Co, Ni, Cu, Zn, Ga, W, Y, Zr, Ba, Hf, and REE. A relative enrichment is found for the elements Be, S, Ag, In, Sn, Sb, Tl, Bi, and Pb. According to the requirements of the European legislation regarding the contents of lead, cadmium, arsenic, clinoptilolite, clay minerals and quartz in the zeolitized rocks, the tuffs from Beli Plast and Most deposits could be used as a sorbent for detoxification purposes.