Assessment of heavy metal(loid) contents of clay bricks manufactured and utilized as structural building material in Türkiye

Abstract

Abstract Heavy metal(loid)s (HMs) originating from natural and anthropogenic activities can have toxic effects on humans even at low concentrations. Clay bricks (CBs), generally produced by mixing clay and water, are formed by firing the air-dried mixture to make them durable and stable. During firing, the CB suffers some chemical and physical changes and turns into a new artificial material. CBs, known as masonry units, have been one of the most used building materials throughout the history of construction. CB may naturally contain HMs depending on the geochemical structure of the clay used in the production phase. In this study, major and minor oxides and HM distributions in forty-five CB samples collected from thirty-one CB factories that provide approximately one-third of the CB utilized in buildings in Türkiye were determined for the first time using an energy-dispersive X-ray fluorescence spectrometer. The average concentrations (in %, dw) of major and minor oxides in CB samples are in order of SiO2 (49.9) > Al2O3 (17.8) > CaO (9.5) > MgO (8.2) > Fe2O3 (7.5) > SO3 (3.6) > Na2O (3.3) > K2O (1.8) > TiO2 (0.9) > P2O5 (0.2) > MnO (0.1). The average concentrations (in mg/kg dw) of Fe, Ti, Mn, Cr, Sr, V, Ni, Zr, Zn, Cu, Co, Pb and As in CB samples were analyzed as 52779, 5329, 736, 341, 23, 192, 190, 110, 85, 44, 39, 14 and 8, respectively. According to the enrichment factor results based on the Earth's crust average, it was revealed that Cr, Ni, and As were naturally moderately enriched.