1. THE SEPARATION AND THE CONCENTRATION OF MINERALS FROM THE ZEOLITIC VOLCANIC TUFFS. ANALYTICAL CONSIDERATIONS. Authors: DUMITRU BULGARIU.2. USE AQUEOUS PEG-INORGANIC SALT TWO-PHASE SYSTEMS FOR Bi(III) EXTRACTION IN THE PRESENCE OF INORGANIC EXTRACTANTS. Authors: LAURA BULGARIU, DUMITRU BULGARIU.3. THE EFFECTS OF HEAVY METALS ON CHEMICAL EQUILIBRIUMS FROM ANTROPIC SOILS. Authors: DUMITRU BULGARIU, LAURA BULGARIU, FEODOR FILIPOV.4. ADSORPTIVE CHARACTERISTICS OF HISTOSOL MODIFIED BY SIMPLE CHEMICAL TREATMENTS FOR Ni(II) REMOVAL FROM AQUEOUS MEDIA. Authors: DUMITRU BULGARIU, LAURA BULGARIU.5. REMOVAL OF Zn(II) IONS FROM AQUEOUS SOLUTION BY ADSORPTION ON MUSTARD HUSKS. Authors: DUMITRU BULGARIU, LAURA BULGARIU.