Characterizing DOC sources in China's Haihe River basin using spectroscopy and stable carbon isotopes. (March 2020)

• Record Type: Journal Article
• Authors: Wen, Zhidan; Song, Kaishan; Liu, Ge; Lyu, Lili; Shang, Yingxin; Fang, Chong; Du, Jia
• Is Part Of: Environmental pollution. Volume 258(2020)
• Publication Date: 2020-03
• Subjects: Dissolved organic carbon -- Carbon sources -- Stable isotopes -- EEM-FRI -- Sewage; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2019.113684
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The Haihe River Basin is a polluted area affected by the developing industry and intensive agricultural activities in China. Dissolved organic matter (DOC) and light-absorbing characteristics of chromophoric dissolved organic matter (CDOM) were monitored in different tributaries of China within the Haihe River basin during spring and autumn. The concentration of DOC during spring was higher than during autumn ( p < 0.01), and the evaporation was an important factor affecting the concentration of DOC in the basin. By contrast, the proportion of inputs due to terrigenous plants during autumn was higher than during spring. Carbon stable isotope analysis δ 13 C and C: N ratio of DOC, evidenced the inputs of DOC in the Haihe River basin from different sources including sewage, terrestrial plants, soil, and plankton. Isotopic analysis of δ 13 C and excitation-emission matrix (EEM) with fluorescence regional integration (FRI) analysis supported the hypothesis that allochthonous inputs contributed substantially to the inputs of DOC in the Haihe River basin, coming largely from sewage (9.8%–81.2%) and terrestrial plants (13.3%–65.8%). Depending on the source of DOC and contribution, four types with different EEM spectra were set. Type I, river water from sewage (81.2%); Type II, river water with input from terrestrial plants (65.8%); Type III, river water with plankton (36.4%), and Type IV, river water with soil-derived DOC (33.9%). The results demonstrated that the combined methodology using 13 C stable isotope and EEM-FRI can be used to characterize the components of DOC in river waters. This approach was important for tracking the concentration and composition of DOC in river waters from different input sources and for better understanding concerning the local regulation of the terrestrial carbon cycle. Graphical abstract: Image 1 Highlights: DOC was successful evaluated integrating δ 13 C and spectroscopy techniques. DOC concentrations of Haihe River in spring was higher than in autumn ( p < 0.01). Evaporation is an important control on DOC concentration in the basin. Allochthonous inputs contribute substantially to the DOC pool in Haihe River Basin. 9.8%–81.2% of DOC in Haihe River Basin was derived from sewage source.