ABSTRACT
All metal ions are present in the earth’s crust in different abundances and oxidation states. There are different ores containing various metal ions. Among the most important ores are bauxite, stibnite, realgar, orpiment and arseno pyrites, chromite, magnatite, pyrolusite and braunite, galena, cinnabar, cassiterite, patronite, and vamidinite and carnotite. The contamination of our environment due to toxic metal ions is a very serious and challenging issue. The industries dealing with arsenic as the raw material can be considered the sources of arsenic contamination at low concentrations. Water is the main component of the ecosystem; unfortunately, it is the most contaminated by toxic metal ions. Because reports of surface water contamination due to heavy metal ions are common, the presence of heavy metal ions in the sediment is also a common finding. Agricultural and other types of soils are contaminated by heavy metal ions.
