Quantification of Methylated Selenium, Sulfur, and Arsenic in the Environment

Abstract

Biomethylation and volatilization of trace elements may contribute to their redistribution in the environment. However, quantification of volatile, methylated species in the environment is complicated by a lack of straightforward and field-deployable air sampling methods that preserve element speciation. This paper presents a robust and versatile gas trapping method for the simultaneous preconcentration of volatile selenium (Se), sulfur (S), and arsenic (As) species. Using HPLC-HR-ICP-MS and ESI-MS/MS analyses, we demonstrate that volatile Se and S species efficiently transform into specific non-volatile compounds during trapping, which enables the deduction of the original gaseous speciation. With minor adaptations, the presented HPLC-HR-ICP-MS method also allows for the quantification of 13 non-volatile methylated species and oxyanions of Se, S, and As in natural waters. Application of these methods in a peatland indicated that, at the selected sites, fluxes varied between 190–210 ng Se·m−2·d−1, 90–270 ng As·m−2·d−1, and 4–14 µg S·m−2·d−1, and contained at least 70% methylated Se and S species. In the surface water, methylated species were particularly abundant for As (>50% of total As). Our results indicate that methylation plays a significant role in the biogeochemical cycles of these elements.

Selenium Cycling Across Soil-Plant-Atmosphere Interfaces: A Critical Review

“…Methylation and volatilization of Se from soils has been of particular interest for bioremediation strategies in high-Se environments that rely on the activity of microbes and vegetation to volatilize Se and thereby reduce Se contamination in the surface environment [ 36 ]. Field emissions of methylated Se have been measured using flux chambers combined with trapping systems (e.g., acid traps or cold traps) [ 261 ]. Sensitive measurements of Se volatilization in laboratory settings have also been obtained by spiking soil and sediment samples with radioactive 75 Se [ 262 ].…”

“…Although quantitative measurements are relatively scarce, the biogenic production of volatile Se compounds and the corresponding Se emissions have been assessed in a variety of environmental compartments including soils and sediments [ 37 , 262 , 263 , 264 , 265 , 266 , 267 ], plant leaves [ 268 ], peat bogs [ 95 , 261 ], estuarine waters [ 268 ], lakes [ 269 ] and in the marine environment [ 92 , 96 ]. A summary of observed biogenic production of volatile Se is provided in Table 2 .…”

Studying selenium and sulfur volatilisation by marine algae Emiliania huxleyi and Thalassiosira oceanica in culture

“…At the end of the incubation period, volatile S and Se compounds were stripped from the batch culture media and trapped in nitric acid, which was previously shown to be a suitable trapping medium for volatile S and Se compounds. [28,29] Following convention, we define volatile Se as encompassing DMSe, dimethyl diselenide (DMDSe), dimethyl selenylsulfide (DMSeS) and other potential gaseous/volatile Se species. Culturing bottles were connected to a glass impinger (25 mL, Labo-Tech, Muttenz, Switzerland) using a PFA BOLA Oliven (Bohlender GmbH, Grunsfeld, Germany) and a minimal amount (,1 cm) of new Tygon flexible silicone tubing (Saint-Gobain Performance Plastics, Charny, France) as shown in Fig.…”

Distribution and behaviour of dissolved selenium in tropical peatland-draining rivers and estuaries of Malaysia

“…During the estuarine mixing, the negative correlation between DOSe / DOC and DOSe / DISe ratios with C2 / C1 ratios is enhanced by photodegradation (Wang et al, 2019; Fig. 5d and e), indicating that, compared to bulk DOM, the DOSe fractions were more susceptible to photodegradation, and that DOSe was probably photodegraded to DISe.…”