Chromium exits naturally in two oxidation states: hexavalent chromium (Cr(VI)) and trivalent chromium (Cr(III)). Cr(VI) is carcinogenic and mutagenic to living organisms and Cr(III) is 100 times less toxic than Cr(VI). ...

Nuclear energy has been proposed as an alternative energy source in the bid to reduce carbon emissions that results from fossil fuel. Hexavalent uranium [U(VI)] is the most abandoned radioactive waste discharged from nuclear ...

Polycyclic aromatic hydrocarbons (PAHs) are known to be resistant to environmental degradation due to their hydrophobicity which results in low solubility in water. PAHs are therefore typically less bioavailable than ...

Cr(VI) is toxic to biological systems due to its strong oxidizing potential. However, some microorganisms possess mechanisms that enable them to reduce the toxic of chromium [Cr(VI)] to the less toxic trivalent state [Cr(III)] ...

Acid mine drainage (AMD) is a worldwide problem caused mainly by mining activities and is known for its adverse impacts on the environment due to low pH, high metal content and high sulphate concentrations. Lime ...

Selenite (SeO3 2-) is a toxic selenium oxyanion which readily bio-accumulates in the food chain. Enterococcus species were found to reduce SeO3 2- to elemental selenium (Se0) more rapidly (in 1 h) as compared to ...

Coal gasification stripped gas liquor (CGSGL) wastewater contains large quantities of complex organic and inorganic pollutants which include phenols, ammonia, hydantoins, furans, indoles, pyridines, phthalates and other ...