Comprehensive study of the occurrence and characteristics of carbon, nitrogen, and phosphorus in sediments and riparian soils of large drinking water reservoir

The contamination of nutrients has caused considerable worry about the environment, resource value, and ecological worth of drinking water reservoirs. Therefore, we comprehensively studied the abundance, sources, distribution, and environmental behavior of carbon, nitrogen, and phosphorus in Fengshuba Reservoir (FSBR) (a large drinking reservoir, China). Seasonal hydrological circumstances had little influence on the nutrient abundance and structural component of the FSBR, while carbon, nitrogen, and phosphorus abundance, composition, and environmental behavior varied significantly between various environmental media (sediment and soil phases). Microbial-derived humus (C1), terrestrial-derived humus (C2), and protein-like tryptophan (C3) were identified as the three primary fluorescence components using parallel factor analysis. The abundance of colored dissolved organic matter (CDOM), molecular weight, aromatization degree, and humification degree of dissolved organic matter (DOM) in the sediment were lower than in the soil, whereas the authigenic component was greater than in the soil, according to spectral index analysis. The main sources of humus in FSBR were biogenic contributions. Principal component analysis indicated that three components were closely associated to phosphorus in the sediment phase, whereas nitrogen and phosphorus in the soil phase were mainly related to C1 and C2. In summary, in the management and control of water environment nutrients in reservoirs, soil media in the riparian zone must be carefully considered.