High Chromium Levels in Soils and Waters: Origin, Effects and Treatment

Chromium (Cr) is a dangerous pollutant occurring into the environment due to anthropogenic activities and natural processes. Cr naturally occurs in several oxidation states, although only the Cr(III) and Cr(VI) species are stable at near-surface environment conditions. It is typically associated with ultramafic rocks and derived soils, because of the Cr(III)-bearing minerals that commonly constitute these lithotypes, such as spinels, pyroxenes, olivines, amphiboles, serpentine minerals, and others. However, due to weathering processes, Cr(III) is oxidizing into highly toxic Cr(VI) species and is widespread into the environment, reaching high levels into soil media and in natural waters used for agricultural and drinking purposes. However, chromium occurrence in the environment is also due to its common use in a large spectrum of industries, such as metallurgical and pigment industries, as well as ferrous and non-ferrous alloy metal fabrication, leather-tanning, and chrome-plating. Considering its negative effects on human health, defining the pollutant's behavior into each environment and developing ad-hoc treatment technologies became an urgent challenge for the scientific community to develop safe land use and a proper water management plan in polluted areas. The Special Issue solicits novel contributions concerning chromium release and fate during weathering processes in different geochemical and geological environments, employing geochemical survey and geochemical modelling to define soil and water pollution. We also welcome contributions regarding multidisciplinary case studies, including environmental exposure to Cr and relating effects on humans and ecosystems due to natural processes and anthropogenic activities. We also encourage contributions concerning the use of conventional and novel technologies for water remediation as well as sustainable management of purify waters and waste products.