Spectral Characteristic Of The Waters With Different Sizes Of Particles: Impact Of Hydrochemical Property And Land Use Type

Natural colloids (NCs) are heterogeneous mixtures of particles in the aquatic environments that are strongly influenced by land use and hydrochemical properties between terrestrial and aquatic environments. However, the relevant study was paid little attention to the difference among the waters with different sizes of particles (e.g., suspended particulate matter-SPM, NCs, and the truly dissolved phase). In this study, the spectral properties of these different waters were investigated from different land-use types in the Yuan River basin, China. Results of the UV-visible absorption spectral showed that with the particle size increased, the aromaticity, chromophoric dissolved organic matter, and humification degree of organic matter increased, while the condensation degree decreased. Data analysis from the fluorescence indices indicated that the source and the autochthonous feature of the truly dissolved water differed from that of NCs and SPM. Whereas the protein-like component was mainly combined with the relatively larger size of particles (i.e., SPM and NCs), especially in the downstream. Redundancy analysis revealed that the spectral characteristics of the water samples were strongly influenced by the hydrochemical parameters (>45%) with comparison to land-use type (nearly 10%). Furthermore, the impact of land-use type on the spectral properties was differed between the large and small scale of the buffer strips and between the mainstream and the tributaries. And this effect was more significant on the fluorescence properties in the mainstream and the spectral properties for NCs than for SPM. The study helps to understand the biogeochemical effects of the waters with different particle sizes.