A new view into the characterization of dissolved organic matter composition in lakes and traceability studies

With the booming socio-economic development and accelerated urbanisation, the problem of water pollution is becoming more and more prominent, which not only puts great pressure on nature, but also poses a serious threat to the production and life of human beings. Therefore, the study of dissolved organic matter fractions in lakes and their accurate traceability is the key to alleviate the ecological pressure. In this study, the three-dimensional fluorescence spectral properties, characteristic parameters and fluorescence characteristics of dissolved organic matter in water bodies were analyzed in depth using Changdang Lake in China as an example. Three methods, peak-finding method, Tucker coefficient and self-organised neural network, were prominently used for the analysis. Combined with conventional water quality parameters, Combined with conventional water quality parameters, this method further reveals the correlation between DOM composition and surrounding pollution sources in Changdang Lake. The results showed that there were four main components of dissolved organic matter in the lake body of Changdang Lake, of which C1, C2 and C4 were humic substances and C3 was protein. In addition, the fluorescence characteristic parameters of Changdang Lake, FI, ranged from 1.64 to 1.75, BIX, ranged from 0.95 to 1.05, and HIX, ranged from 0.5 to 0.65, which indicated that the increment of dissolved organic matter in Changdang Lake was mainly a mixture of endogenous and exogenous inputs. Through the joint interpretation of peak discovery, data presentation and result visualisation, it was found that these fluorescence fractions were extremely similar to those of the surrounding aquaculture and textile printing and dyeing. The results of this study not only provide effective data support for the local environmental protection department of Changdang Lake, but also provide a useful reference for pollution traceability in other lake basins.