Biologically induced formation of realgar deposits in soil

Arsenic Forms in Soils of Various Settings in the Historical Ore Mining and Processing Site of Radzimowice, Western Sudetes

“…However, the burial of sediments over time or drop of redox potential due to temporal flooding could promote the release of As from sediments via reductive dissolution [15][16][17][18]32,51]. Although a field analysis of redox was not performed, the presence of hydromorphic features in soil samples 6 and 7 proves that those soils are subjected temporarily to reducing conditions that are particularly favorable for the release of As as a result of reductive dissolution of (hydroxy)Fe-oxides, although they do not cause the formation of secondary As-hosted sulfides reported from strongly anoxic conditions [21,47,54,55]. In our research, no sulfide As minerals As were identified in the sediment 5(S) or in the soil No.…”

Formation of Zn and Pb sulfides in a redox-sensitive modern system due to high atmospheric fallout

“…Arsenic was not detected in the sulfides (see Figs S4 and S5) despite comparable to Cd contents in peat (Table S3) and higher porewater concentrations (Table 1 and Table S2). The work of Drahota et al (2017) suggests a requirement of more reducing conditions for the reduction of As(V) to As (III) in excess of organic matter. Organo-arsenic compounds are known to form in peatlands subjected to gross air pollution (Mikutta and Rothwell, 2016).…”

As and S Speciation in a Submarine Sulfide Mine Tailings Deposit and its Environmental Significance the Study Case of Portmán Bay (Se Spain)

“…This is in agreement with the obvious (and measured) presence of organic matter in the investigated cores, including large-sized vegetal remnants and dark colors typical of organic matter loaded deposits, therefore defining a favourable environment for SRB to thrive (Figs. 1 and 7) (Alam and McPhedran, 2019;Baza-Varas et al, 2022;Drahota et al, 2017;Kerr et al, 2018;Rodriguez-Freire et al, 2016). Realgar and orpiment would consist of tiny and disseminated particles, stable under the reducing conditions -with a measured interstitial water pH of 6-of the submarine mine tailings deposit (Alam and McPhedran, 2019;Kerr et al, 2018;Le Pape et al, 2017;Newman et al, 1997).…”

“…Realgar and orpiment would consist of tiny and disseminated particles, stable under the reducing conditions -with a measured interstitial water pH of 6-of the submarine mine tailings deposit (Alam and McPhedran, 2019;Kerr et al, 2018;Le Pape et al, 2017;Newman et al, 1997). The precipitation of tiny (submicron) realgar and orpiment particles by SRB has been proposed as an effective removal mechanism of As in heavily contaminated waters and mine tailings (Briones-Gallardo et al, 2017;Drahota et al, 2017;Gadd, 2010;Kerr et al, 2018;Le Pape et al, 2017). The submicron size of realgar and orpiment particles would explain the non-observation of realgar and orpiment grains of convenient size in the examined samples.…”