Chromium behavior in aquatic environments: a review

Abstract

The fate of chromium (Cr) – a redox sensitive metal – in surface sediments is closely linked to early diagenetic processes. This review summarizes the main redox pathways that have been clearly identified over recent decades concerning the behavior of Cr(III,VI) in aquatic environments, and applies them to surface sediments where data for redox speciation remain limited. Overall, abiotic redox reactions that govern the speciation of Cr involve manganese (Mn) (III,IV) (hydr)-oxydes for Cr(III) oxidation, Cr(VI)-reducing species (dissolved iron (Fe) (II) and hydrosulfide (HS)−), and Cr(VI)-reducing phases (ferrous and sulfide minerals, as well as Fe(II)-bearing minerals). Bacterial activity is also responsible for the redox interconversion between Cr(III) and Cr(VI): biotic reduction of Cr(VI) to Cr(III) is observed through either detoxification or dissimilatory reduction. Whereas Mn(II)-oxidizing bacteria are known to promote indirect oxidation of Cr(III) to Cr(VI), the reaction mechanisms are unresolved. Conversely, oxygen (O2), nitrate (NO3−), and nitrite (NO2−) do not appear to play any role in Cr(III) oxidation. Additionally, Mn(II) and ammonium (NH4+) are not known to promote Cr(VI) reduction. Once reduced, the mobility of Cr(III) in sediments is significantly restricted and regulated by precipitation and sorption processes. Finally, even if the role of natural organic matter in sediment has been determined, further research is required to identify the complexation mechanisms.

Chromium Pollution in European Water, Sources, Health Risk, and Remediation Strategies: An Overview

“…However, levels of Cr (VI) exceeding 70-90 µg L −1 in groundwater and water have been frequently measured as a result of man-made pollution [19,32,33]. Industrial use and urban source in fact are closely related to Cr (VI) accumulation in sediments and waters [34]. For example, the improper disposal of chromite ore processing residues, that is stocking them in open dump sites, results in a rapid migration by leaching of soluble contaminants into surface waters and groundwater [33,35].…”

Insight into pH dependent Cr(VI) removal with magnetic Fe3S4

“…Chromium (Cr) is widely used in industrial processes, such as textile dying, tanneries, galvanic industry and wood preservation [1,2]. Due to its dissolubility, persistence and bioaccumulation, Cr is frequently detected in groundwater, surface water and soil [3].…”

Microplastics as Vectors of Chromium and Lead during Dynamic Simulation of the Human Gastrointestinal Tract

“…Cr 3+ in solution can form different complexes or can precipitate depending on the ions present in the medium, the pH, and other factors (Gorny et al, [48]). Most researchers indicate the precipitation of Cr as hydroxide from pH 5-6 (Fendorf, [49]; Rai et al, [50]), although it can also precipitate as oxide, depending on the aqueous medium conditions.…”