In-situ measurement of dissolved sulfide in surface sediment porewater using diffusive gradients in thin films (DGT) coupled with digital imaging

Zhaoyang Gu; Dongxing Yuan; Yongming Huang; Kunde Lin

doi:10.1016/j.scitotenv.2023.169784

In-situ measurement of dissolved sulfide in surface sediment porewater using diffusive gradients in thin films (DGT) coupled with digital imaging

Sci Total Environ. 2024 Mar 1:914:169784. doi: 10.1016/j.scitotenv.2023.169784. Epub 2024 Jan 4.

Authors

Zhaoyang Gu¹, Dongxing Yuan¹, Yongming Huang¹, Kunde Lin²

Affiliations

¹ Fujian Provincial Key Laboratory for Coast Ecology and Environmental Studies, College of the Environment and Ecology, Xiamen University, Xiamen 361102, China.
² Fujian Provincial Key Laboratory for Coast Ecology and Environmental Studies, College of the Environment and Ecology, Xiamen University, Xiamen 361102, China. Electronic address: link@xmu.edu.cn.

PMID: 38181945
DOI: 10.1016/j.scitotenv.2023.169784

Abstract

Dissolved sulfide in sediment porewater significantly influences aquatic ecosystems. Conventionally, sulfide determination in sediment porewater relies on ex-situ analytical methods, susceptible to measurement errors due to sulfide oxidation and volatilization during sample analysis. In this study, we introduced an innovative in-situ method for assessing dissolved sulfide in surface sediment porewater, leveraging the integration of diffusive gradients in thin films (DGT) with digital imaging. The DGT device effectively concentrates sulfide in sediment porewater, inducing observable color changes in the binding gel. Recordings of these changes, captured by imaging equipment, facilitated the establishment of calibration curves correlating grayscale value alterations in the binding gel to sulfide concentrations. Under optimal conditions, the developed method demonstrated a linear detection range of 3.0-200 μmol L^-1 at 20 °C, particularly when the exposure time exceeded 180 min. The developed method is insensitive to salinity and suitable for measuring sulfide concentrations in various natural water environments. Compared to traditional ex-situ methods, our approach circumvents challenges linked to intricate pre-treatment, prolonged analysis duration, and significant systemic errors. This proposed method presents a real-time solution for sulfide concentration assessment in surface sediment porewater, empowering researchers with an efficient means to monitor and study dynamic sulfide levels.

Keywords: Diffusive gradients in thin films (DGT); Digital imaging technology; In-situ measurement; Sediment porewater; Sulfide.