Assessment of heavy metals in tailings and their implications on human health
Ismail Adeniyi Okewale, Hendrik Grobler
Abstract
• Heavy metal in tailings and its implication on human health. • Chemical, mineralogical and heavy metal analyses. • Significant heavy metals are chromium, copper, zinc, lead, arsenic and cobalt. • Heavy metals that can affect human health are copper, zinc and chromium. • Tailings must be evaluated before engineering applications. The need for rapid industrial and national growth necessitates exploration and exploitation of mineral deposit. These processes in turn produce unwanted materials called tailings. These materials often contain toxic and heavy metals with the potential of having adverse effect on the environment and human. In this study, an assessment was made into the presence of heavy metals in tailings and their effects on human health by conducting index tests, chemical analysis, mineralogical analysis and heavy metal analysis using Atomic Absorption Spectrometry (AAS). The tailings were obtained from dumps where the materials were deposited after mining and beneficiation processes have been carried out on the parent rock to obtain pure and valuable compositions. The tailings are poorly graded in nature. Silica dominated the composition followed by iron particularly in iron tailings and then the alumina. Quartz has the highest proportions in terms of mineralogy. The percentage of haematite is high in iron tailings. The most significant heavy metals in the tailings are chromium Cr, copper Cu, zinc Zn, lead Pb, arsenic As and cobalt Co. However, the heavy metals that have potential to affect human adversely are in the order: Cu > Cr for the iron and gold tailings and Cu > Zn > Cr for tin tailings. Due to the presence of abundant heavy metals that are dangerous to human health in the tailings, these materials must be evaluated individually before their use as engineering materials and for engineering applications.