Optical measurements of dissolved organic matter as proxies for CODMn and BOD5 in plateau lakes

Xuan Yang; Yongqiang Zhou; Xiaoying Yang; Yunlin Zhang; Robert G M Spencer; Justin D Brookes; Erik Jeppesen; Hucai Zhang; Qichao Zhou

doi:10.1016/j.ese.2023.100326

Optical measurements of dissolved organic matter as proxies for COD_Mn and BOD₅ in plateau lakes

Environ Sci Ecotechnol. 2023 Sep 29:19:100326. doi: 10.1016/j.ese.2023.100326. eCollection 2024 May.

Authors

Xuan Yang^{1

2

3}, Yongqiang Zhou⁴, Xiaoying Yang^{1

2}, Yunlin Zhang⁴, Robert G M Spencer⁵, Justin D Brookes⁶, Erik Jeppesen^{1

7

8

9

10}, Hucai Zhang¹, Qichao Zhou^{1

11}

Affiliations

¹ Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650500, China.
² Institute of International River and Eco-security, Yunnan University, Kunming, 650500, China.
³ Zhejiang College of Security Technology, Wenzhou, 325016, China.
⁴ Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
⁵ Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, 32306, United States.
⁶ Water Research Centre, School of Biological Science, The University of Adelaide, Adelaide, 5005, Australia.
⁷ Department of Ecoscience, Aarhus University, Aarhus, 8000, Denmark.
⁸ Sino-Danish Centre for Education and Research, Chinese Academy of Sciences, Beijing, 100101, China.
⁹ Limnology Laboratory, Department of Biological Sciences and Centre for Ecosystem Research and Implementation, Middle East Technical University, Ankara, 06800, Turkey.
¹⁰ Institute of Marine Sciences, Middle East Technical University, Erdemli, Mersin, 33731, Turkey.
¹¹ Yunnan Key Laboratory of Pollution Process and Management of Plateau Lake-Watershed, Yunnan Research Academy of Eco-environmental Sciences, Kunming, 650034, China.

Abstract

The presence of organic matter in lakes profoundly impacts drinking water supplies, yet treatment processes involving coagulants and disinfectants can yield carcinogenic disinfection by-products. Traditional assessments of organic matter, such as chemical oxygen demand (COD_Mn) and biochemical oxygen demand (BOD₅), are often time-consuming. Alternatively, optical measurements of dissolved organic matter (DOM) offer a rapid and reliable means of obtaining organic matter composition data. Here we employed DOM optical measurements in conjunction with parallel factor analysis to scrutinize COD_Mn and BOD₅ variability. Validation was performed using an independent dataset encompassing six lakes on the Yungui Plateau from 2014 to 2016 (n = 256). Leveraging multiple linear regressions (MLRs) applied to DOM absorbance at 254 nm (a₂₅₄) and fluorescence components C1-C5, we successfully traced COD_Mn and BOD₅ variations across the entire plateau (68 lakes, n = 271, R² > 0.8, P < 0.0001). Notably, DOM optical indices yielded superior estimates (higher R²) of COD_Mn and BOD₅ during the rainy season compared to the dry season and demonstrated increased accuracy (R² > 0.9) in mesotrophic lakes compared to oligotrophic and eutrophic lakes. This study underscores the utility of MLR-based DOM indices for inferring COD_Mn and BOD₅ variability in plateau lakes and highlights the potential of integrating in situ and remote sensing platforms for water pollution early warning.

Keywords: Biochemical oxygen demand; Chemical oxygen demand; Dissolved organic matter; Water quality; Yungui plateau lakes.