A Wind Tunnel for Measuring Selenium Volatilization under Field‐Like Conditions

• Published in: Journal of environmental quality Vol. 29; no. 2; pp. 460 - 466
• Main Authors: Dungan, R. S., Stork, A., Frankenberger, W. T.
• Format: Journal Article
• Language: English
• Published: Madison, WI American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America 01.03.2000; Crop Science Society of America; American Society of Agronomy
• Subjects: AIR-BIOSPHERE INTERACTIONS; Analysis methods; Applied sciences; Atmospheric pollution; Dispersed sources and other; ENVIRONMENTAL SCIENCES; ENVIRONMENTAL TRANSPORT; Exact sciences and technology; MONITORING; Pollution; Pollution sources. Measurement results; SELENIUM; SOILS; VOLATILITY; WIND TUNNELS; Natural origin pollution; Atmospheric condition; Radioactive tracers; Pollutant emission; Selenium 75; Wind tunnel; Medium effect; Volatilization; Air pollution; Air ground interface; Measurement method; Selenium; Field study
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2000.00472425002900020014x

A wind tunnel was developed to measure the loss of volatile selenium (Se) from soil under field‐like conditions. The wind tunnel consisted of a volatilization chamber made of Plexiglas (2.4 m long × 0.8 m wide × 1.2 m high), which was set above a stainless steel lysimeter (0.5 m2 surface area × 0.8 m deep). High air exchange rates (avg. 700 air changes h−1) were used to simulate field‐like environmental conditions inside the wind tunnel. To monitor the fate and transport of the Se, radiolabeled 75Se as sodium selenite (Na275SeO3) was incorporated into the top 5 cm of soil. Volatile Sc was trapped on activated carbon filters and measured directly using gamma counting. A 135‐d bare‐soil experiment was carried out, during which 2.7% of the Se was released through volatilization without added C. The average flux rate of gaseous Se was 17 mg m−2 h−1, with a high of 72 mg m−2 h−1 occurring on Day 6. After 135 d, 59 and 34% of the 75Se was located in the 0 to 5 and 5 to 10 cm soil layers, respectively. A total of 84.5% of all applied 75Se was recovered. The purpose of this study was to improve estimates on Se volatilization from seleniferous soils and help close the gap between previous laboratory and field experiments.