Grain Size Distribution Characteristics of Suspended Particulate Matter as Influenced by the Apparent Pollution in the Inorganic Type Urban Landscape Water: Taking the Canal of Suzhou Section as Example

Abstract

Grain size distribution characteristics of suspended particulate matter(SPM) provides important information for water environment apparent quality. The size distribution characteristics and influencing factors of suspended particulate matter under different apparent pollution levels in the inorganic type urban landscape water were discussed taking the canal which is flowing through Suzhou as the research object. The apparent pollution mechanism of inorganic type urban landscape water was explained from the aspect of the size of the suspended particles. The results showed that: SPM had mainly a uni-modal distribution in the inorganic type water, and the median particle diameter range was 13-25.2 μm. The component Ⅱ was perdominant, and the particle size range was 3.8-16 μm(with an average volume fraction of 29.4%-59.6%). Sensitive components of the apparent polluted water were component Ⅱ and component Ⅳ (particle size range 32-64 μm). The relation of the sensation pollution index(SPI) and component Ⅱ was segmented, and the node was 45NTU. When the turbidity was less than 45NTU, SPI value and volume fraction of component Ⅱ had a significant positive correlation, and volume fraction of component Ⅳ had a significant negative correlation with SPI value; when the turbidity was equal to or greater than 45NTU, the correlation was the opposite. The influencing factors of particle size distribution of Suzhou canal mainly included organisms and hydrodynamic conditions. The biological factors mainly led to increase of the algae and the hydrodynamic condition caused resuspension and increased the large particles.