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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.

The resource, environment, and ecological value of drinking reservoirs have received widespread concerns due to the pollution of persistent organic pollutants such as polycyclic aromatic hydrocarbons (PAHs). Therefore, we comprehensively studied the occurrence, source, distribution and risk assessment of representative PAHs in Fengshuba Reservoir (FSBR) (large drinking reservoir, China). The total concentrations of 16 USEPA PAHs in the water phase, porewater phase, sediment phase and soil phase were in ranges of 109.72-393.19 ng/L, 5.75-35.15 μg/L, 364.4-743.71 μg/kg and 367.81-639.89 μg/kg, respectively. The naphthalene (Nap) was the dominant PAHs in the water phase, while it was Nap and phenanthrene (Phe) in porewater, sediment and soil phase. The main sources of PAHs in FSBR were biomass combustion. Redundancy analysis indicated that, the NTU, NO2-, NH4+, Chl-α and IC were the dominant factor influencing the PAHs distribution in water phase and the PAHs in sediment phase was affected by T and NO3-. Pseudo-partitioning coefficients indicated that the PAHs in the porewater phase was more likely to migrate to the sediment phase. Risk assessment indicated that the PAHs both in the water and sediment phases were generally in a Low-risk state, while the PAHs in the soil phase were in a Moderate-risk state and the Nap was in a High-risk state, and exposure to the PAHs in FSBR through drinking and skin exposure had little impact on consumers' health. In summary, Nap could be used as a key indicator to evaluate the existence and potential risk of PAHs in FSBR.