this region is flooded and become a reservoir for drinking water and irrigation. Samples collected from the reservoir showed the higher concentration of cadmium (Cd) and lead (Pb) that exceeded regulatory guidelines. Applications Slags can serve other purposes, such as assisting in the temperature control of the smelting, and minimizing any re-oxidation of the final liquid metal product before the molten metal is removed from the furnace and used to make solid metal. In some smelting processes, such as ilmenite smelting to produce titanium dioxide, the slag can be the valuable product. Ancient uses During the Bronze Age of the Mediterranean area there were a vast number of differential metallurgical processes in use. A slag by-product of such workings was a colorful, glassy material found on the surfaces of slag from ancient copper foundries. It was primarily blue or green and was formerly chipped away and melted down to make glassware products and jewelry. It was also ground into powder to add to glazes for use in ceramics. Some of the earliest such uses for the by-products of slag have been found in ancient Egypt. Historically, the re-smelting of iron ore slag was common practice, as improved smelting techniques permitted greater iron yields—in some cases exceeding that which was originally achieved. During the early 20th century, iron ore slag was also ground to a powder and used to make agate glass, also known as slag glass. Modern uses Construction Utilization of slags in the construction industry dates back to the 1800s, where BF slags were used to build roads, and railroad ballast. During this time, it was also used as an aggregate and have begun being integrated into the cement industry as a geopolymer. Today, ground granulated blast furnace slags (GGBFS) are used in combination with Portland cement (PC) to create "slag cement." GGBFS react with portlandite (Ca(OH)2), which is formed during cement hydration, via the pozzolanic reaction to produce cementitious properties that primarily contribute to the later strength gain of concrete. This leads to concrete with reduced permeability and better durability. Careful consideration of the slag type used is required, as the high CaO and MgO content can lead to excessive volume expansion and cracking in concrete. These hydraulic properties have also been used for soil stabilization in roads and railroads constructions. Slag is used in the manufacture of high-performance concretes, especially those used in the construction of bridges