Study on the influence of soil properties on fluorescence intensity of polycyclic aromatic hydrocarbons

The properties of soil matrix have an impact on the fluorescence intensity of polycyclic aromatic hydrocarbons (PAHs), which restricts the application of fluorescence spectral technology in detecting PAHs in soil. The present study explored the mechanism of the influence of soil matrix properties on the fluorescence intensity of PAHs from the perspective of specific surface area (SSA). A three-factor three-level experimental design was adopted for investigating the relationship between soil matrix properties, PAH fluorescence intensity, and soil SSA. The typical benzo[ghi]perylene pollutant in soil as the research object, 27 soil samples with different sand content, moisture content, humic acid content, and given benzo[ghi]perylene concentration (2 mg/g) were prepared. On the basis of obtaining the fluorescence spectra and SSA data of soil samples, statistical analyses of fluorescence intensity and SSA were investigated in relation to the soil matrix properties. The statistical results showed that the soil matrix properties had a significant influence (P < 0.05) on the fluorescence intensity and SSA. Furthermore, combined with the technology of fluorescence microscopy imaging, the influence mechanism of soil matrix properties on fluorescence intensity was revealed. The soil matrix properties affected the soil SSA, resulting in a change of benzo[ghi]perylene concentration in the soil surface at the probe window, thereby affecting the fluorescence intensity.