**2.3 Iron and aluminum concentration**

Iron and aluminum have different geochemical conditions than other heavy metals present in AMD. These two elements are considered seriously due to their higher concentration and effects over other metals. They form a coating along the water stream known as yellow-orange Fe oxy-hydroxides and white-yellow Al oxyhydroxides as shown in **Figure 2**. For low solubility in nature, these two metals under natural conditions form coloration over the water stream for a long time [6].

**Figure 2.** *Coloration of AMD water.*
