Natural attenuation of antimony and arsenic in soils at the abandoned Sb-deposit Poproč, Slovakia

Antimony Sorption to Goethite: Effects of Fe(II)-Catalyzed Recrystallization

“…80 The pH-dependent favorability of tripuhyite in acidic microenvironments might partly explain the cooccurrence of both nanotripuhyite and Sb(V)-bearing goethite in close proximity under otherwise near-neutral conditions in tailings-derived soil. 12 However, very low pH arguably does not reflect the majority of Sb-contaminated systems, which instead are often characterized by near-neutral pH. 7,8,10,14,19,23 Figure 10 shows that, under the pH 7 experimental conditions, all of the data points from this study plot below the stability boundary between goethite and nanotripuhyite.…”

“…These Sb(V) concentrations were selected to achieve Sb(V)/Fe(III) ratios that are representative of in situ Sb(V)-bearing Fe(III) oxides at Sbcontaminated sites. 7,11,12,19,33 The equilibration solution contained 0.01 M KCl as a background matrix and was buffered at pH 7 with 0.05 M 3-(N-morpholino) propane sulfonic acid (MOPS). The goethite suspensions were placed on an orbital shaker (80 rpm) inside an anaerobic chamber and were allowed to equilibrate for 7 days.…”

“…Antimony is a toxic and carcinogenic metalloid, and its release into the environment threatens soil and water quality, ecosystem processes, and human health. − Particularly severe environmental contamination has been reported in relation to Sb mining and ore-processing activities. − Antimony is also released during mining of many other metals (e.g., copper, gold, lead, and zinc) due to its common enrichment in metal sulfide ores. − Other major sources of Sb release to the environment include shooting range soils (leaching of Sb during weathering of bullets) − and disposal of plastic waste (especially Sb-rich E-waste such as computer plastics and consumer electronics). ,, …”

“…A robust understanding of the geochemical behavior of Sb is critical to dealing with existing contamination as well as controlling Sb mobilization from future activities. − Previous studies have shown that Sb­(V) is typically the predominant Sb oxidation state in near-surface soils and sediments, often even under reducing flooded conditions. ,,, A strong association of Sb­(V) with Fe­(III) oxides [a term used here to include oxides, hydroxides, and (oxy)­hydroxides] has been found by in situ observations of Sb enrichment in Fe­(III) oxide minerals, ,, selective extraction analyses on soils/sediments, macroscopic sorption studies using pure mineral phases, ,− and synchrotron-based X-ray absorption spectroscopy (XAS) to characterize in situ Sb speciation. ,,, Sorption of Sb­(V) by Fe­(III) oxides therefore plays a critical role in controlling Sb behavior in natural environments (e.g., soils, sediments, oxidized ore bodies) as well as engineered systems (e.g., tailings and waste rock repositories, reactive barriers, water-treatment wetlands).…”

Improving Long-term Monitoring of Contaminated Groundwater at Sites where Attenuation-based Remedies are Deployed

“…In the interim, extensive research was done to demonstrate that MNA was a safe and effective remediation strategy for metals and radionuclides under the right circumstances. The abundance of research in other countries on natural and engineered attenuation of metals and radionuclides (e.g., Blowes et al 2000; Lee and Hartwig 2005;LaPointe et al 2005;Fytas 2010; Krishna et al 2010;Vázquez et al 2011;Jurkovič et al 2019;Wang et al 2019;Sakala et al 2020) suggests that these will become accepted remedies in other countries as well, increasing the need for efficient long-term monitoring.…”