A method for quantifying the contribution of algal sources to CODMn in water bodies based on ecological chemometrics and its potential applications

Abstract

In natural water bodies, especially in eutrophic or waterbloom water bodies, algal sources are an important source of the permanganate index (CODMn), and their contribution ratio and analytical methods for rapid and quantitative require more research. In this study, continuous monitoring sampling was conducted in the Jiuqu River Basin of the Tuojiang River, and the response relationship between the algal community structure and the CODMn of the overlying water was analysed by detecting and analysing algal biomass, river water quality indicators, algal source organic matter characteristics and the component characteristics of river CODMn. A rapid quantitative analysis model of algal-source CODMn contribution was established based on ecological chemometrics with coupled chlorophyll indicators. Studies have shown that algal abundance is closely related to the dynamic changes in CODMn in water bodies, especially Cyanobacteria, which have a significant advantage in water bodies with high concentrations of CODMn and can be indicating oxygen-depleted polluted water bodies. The contribution of nascent humic substances in algal source material to the CODMn of the overlying water was greater than that of protein substances. The contribution of chlorophyll-a to the estimate of CODMn from algal sources in this study watershed was modeled as CODMn%=[(0.1077Chla−0.1483)/Overlying waterCODMn]×24.50%, and the components and the methods for establishing of an automatic algal sources CODMn monitoring and analysis system were proposed. This study provides technical support for the research and quantitative control of oxygen depletion pollution in rivers, lakes and reservoirs during the waterbloom period.