Effect of Moisture Content on Selenate and Selenite Determination Using DGT

Traditional studies on transforming selenate and selenite are often limited by static measurements and low spatial resolution. They do not fully consider the impact of moisture content. This paper uses the DGT (diffusive gradients in thin films) technique to deeply explore how moisture changes affect the transformation of selenate and selenite in the environment (changes in properties over time). First, representative soil samples (loess) are prepared, and their moisture content is adjusted. Fixed concentrations of selenate and selenite are added, and then the DGT device simulates their migration in the natural environment. The experiment covers drought, moisture, and high moisture environments, and the experiment is repeated under each condition to ensure the accuracy of the data. The sample quality is verified and further analyzed by ion chromatography (IC) and atomic absorption spectroscopy (AAS). This article uses DGT technology to study the influence of moisture content on the migration and transformation of selenate and selenite in soil. Results indicate that increased moisture content leads to higher concentrations, diffusion rates, and DGT capture efficiency of both selenium species, highlighting the importance of moisture in their environmental behavior. When the moisture content increased from 25% to 65%, the coefficient of variation of selenate and selenite increased. The DGT technique proved effective in capturing spatial heterogeneity and providing high-precision measurements, offering robust data to advance research on selenium behavior in soils.