Characterization and mobility of arsenic and heavy metals in soils polluted by the destruction of arsenic-containing shells from the Great War

Abstract

Destruction of chemical munitions from World War I has caused extensive local top soil contamination by arsenic and heavy metals. The biogeochemical behavior of toxic elements is poorly documented in this type of environment. Four soils were sampled presenting different levels of contamination. The range of As concentrations in the samples was 1937-72,820mg/kg. Concentrations of Zn, Cu and Pb reached 90,190mg/kg, 9113mg/kg and 5777mg/kg, respectively. The high clay content of the subsoil and large amounts of charcoal from the use of firewood during the burning process constitute an ample reservoir of metals and As-binding materials. However, SEM-EDS observations showed different forms of association for metals and As. In metal-rich grains, several phases were identified: crystalline phases, where arsenate secondary minerals were detected, and an amorphous phase rich in Fe, Zn, Cu, and As. The secondary arsenate minerals, identified by XRD, were adamite and olivenite (zinc and copper arsenates, respectively) and two pharmacosiderites. The amorphous material was the principal carrier of As and metals in the central part of the site. This singular mineral assemblage probably resulted from the heat treatment of arsenic-containing shells. Microbial characterization included total cell counts, respiration, and determination of As(III)-oxidizing activities. Results showed the presence of microorganisms actively contributing to metabolism of carbon and arsenic, even in the most polluted soil, thereby influencing the fate of bioavailable As on the site. However, the mobility of As correlated mainly with the availability of iron sinks.

Microbial community response to environmental changes in a technosol historically contaminated by the burning of chemical ammunitions

“…Despite the severe contamination, microorganism activity, contributing to carbon (C) and As biogeochemistry, was detected in this technosol (Thouin et al, 2016). However, the structure of the microbial community on this particular site has not yet been determined.…”

“…In previous work, we showed that intrinsic organic matter (OM), mainly composed of charcoal from the contaminated material, is very high (≈ 25 %) (Thouin et al, 2016). This OM is characterized by high C/N (≈ 35) and low hydrogen index/oxygen index (HI/OI ≈ 0.1) and is therefore recalcitrant in nature (Thouin et al, 2018).…”

“…Between 1926 and 1928, more than 200,000 Blue Cross shells containing the Clark I and Clark II agents were destroyed on this site by thermal treatment (Hubé, 2017). The residues from this combustion formed a black layer containing slag, coal, ash and ammunition residues (Bausinger et al, 2007;Thouin et al, 2016). The layer is highly contaminated with As, zinc (Zn), copper (Cu) and lead (Pb) (which concentrations respectively reach 72.8 g.kg -1 , 90.2 g.kg -1 , 9.1 g.kg -1 and 5.8 g.kg -1 ) forming unexpected mineralogical associations (Thouin et al, 2016).…”

“…The residues from this combustion formed a black layer containing slag, coal, ash and ammunition residues (Bausinger et al, 2007;Thouin et al, 2016). The layer is highly contaminated with As, zinc (Zn), copper (Cu) and lead (Pb) (which concentrations respectively reach 72.8 g.kg -1 , 90.2 g.kg -1 , 9.1 g.kg -1 and 5.8 g.kg -1 ) forming unexpected mineralogical associations (Thouin et al, 2016). Organic contamination was also observed with the detection of nitroaromatic explosives and their derivatives (Bausinger et al, 2007), dioxins, furans, polycyclic aromatic hydrocarbons (PAH) and diphenylarsinic acid (Thouin et al, 2017).…”

Concentrations of potentially toxic elements and soil environmental quality evaluation of a typical Prosecco vineyard of the Veneto region (NE Italy)

“…There is an inverse correlation between pH (slight to moderate alkaline) and metals (e.g., pH-Al = − 0.19 and pH-Mn = −0.43). Several studies have found a negative correlation between pH and metal mobility; elements are more mobile in acid conditions (Wang et al 2006;Fanrong et al 2011;Thouin et al 2016) and their increasing absorption in plants and humans threatens their health (Saiful Islam et al 2015;Gu et al 2016). Organic carbon does not show any strong or appreciable correlation with the considered variables.…”