## 3 Results and Discussion
### Fluorescence EEM and Fluorescence Regional Integration (FRI)
The P1I,n and P1V,n fractions can be attributed to the Geo fractions; the HHS Geo percentages (40.7 \(\pm\) 1.5%) were significantly lower than LHS (46.9 \(\pm\) 2.8%) (\(p\) = 0.002). The HHS's high Bio and low Geo fractions reflected that the HHS had lower HIX values than LHS (Figure 1b). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Sample** & **P1,n (\%)** & **P1,n (\%)** & **P1I,n (\%)** & **P1I,n (\%)** & **P1V,n (\%)** & **P1V,n (\%)** \\ \hline ADBHS & 18.3 \(\pm\) 0.9 & 22.0 \(\pm\) 0.3 & 23.7 \(\pm\) 0.2 * & 15.7 \(\pm\) 0.4 & 20.1 \(\pm\) 0.6 \\ FDBHS & 19.3 \(\pm\) 0.3 & 22.7 \(\pm\) 0.1 & 22.1 \(\pm\) 0.2 & 16.6 \(\pm\) 0.3 & 19.3 \(\pm\) 0.1 \\ ADHHS & 18.8 \(\pm\) 0.1 * & 20.8 \(\pm\) 0.3 & 21.2 \(\pm\) 0.6 & 18.5 \(\pm\) 0.9 & 20.7 \(\pm\) 0.1 * \\ FDHHS & 20.1 \(\pm\) 0.3 & 21.4 \(\pm\) 0.3 & 20.0 \(\pm\) 0.6 & 19.0 \(\pm\) 0.5 & 19.5 \(\pm\) 0.3 \\ ADHHS & 18.9 \(\pm\) 1.0 & 24.8 \(\pm\) 0.6 & 26.1 \(\pm\) 1.0 & 11.5 \(\pm\) 0.5 & 18.6 \(\pm\) 0.6 \\ FDHHS & 20.5 \(\pm\) 0.8 & 25.6 \(\pm\) 0.5 & 25.3 \(\pm\) 0.6 & 10.9 \(\pm\) 0.2 & 17.6 \(\pm\) 0.7 \\ ADLHS & 14.7 \(\pm\) 0.8 * & 25.9 \(\pm\) 2.4 & 29.8 \(\pm\) 0.8 * & 11.2 \(\pm\) 0.4 & 18.4 \(\pm\) 2.5 \\ FDLHS & 16.5 \(\pm\) 0.6 & 26.3 \(\pm\) 0.6 & 27.7 \(\pm\) 0.8 & 11.6 \(\pm\) 0.5 & 17.8 \(\pm\) 0.7 \\ \hline \hline \end{tabular}
* significant difference (\(p\) < 0.05) between the ADS and FDS samples.  
\end{table} 
Table 3: Percentages of fluorescence region integration (FRI) among HHS, MHS, and LHS of the AD and FD samples. The SUVA\({}_{254}\) and HIX had a negative correlation (r = \(-\)0.41, \(p\) = 0.049). The SUVA\({}_{254}\) had a significantly positive correlation with the percentage of Bio fractions (r = 0.64, \(p\) < 0.001), but the HIX had a significantly positive correlation with the percentage of Geo fractions (r = 0.93, \(p\) < 0.001). The river water received livestock wastewater containing a great amount of low humification particulate organic matter (POM). The POM that was deposited in the sediment suffered anaerobic biochemical oxidation, which resulted in low aromaticity and low humification in the sediment organic matter. The hydrolysis and oxidation cleavage processes in an anaerobic sediment environment favored decomposing low molecular weight and labile POM [1,4]. The remaining low molecular weight SHS in sediment, after hydrolysis and oxidation cleavage, greatly increased humification compared to the high molecular weight SHS. The HIX significantly correlated with fulvic acid-like (r = 0.76, \(p\)< 0.001) and geochemical fractions. The SUVA\({}_{254}\) values (Figure 1a) suggested that the bulk and size-fractionated SHS attributed to the hydrophilic aromatic substances; this implied that the sediment organic matter did not develop abundant aromaticity. The biochemical fraction that influenced the SUVA\({}_{254}\) values strongly correlated with the Bio fraction, which suggested aromaticity in the SHS in the present study sediment. Besides the percentages of FRI fractions, the present study investigated FRI ratios P\({}_{\rm III,n}\)/P\({}_{\rm II,n}\) for the size-fractionated SHS. The P\({}_{\rm III,n}\)/P\({}_{\rm II,n}\) ratios were 1.11 \(\pm\) 0.11 (LHS) \(>\) 1.02 \(\pm\) 0.06 (MHS) \(>\) 0.98 \(\pm\) 0.05 (HHS) and had a significantly positive correlation with the HIX (r = 0.96, \(p\)< 0.001, Figure 4). The P\({}_{\rm III,n}\)/P\({}_{\rm II,n}\) ratios reflected the extent of humification of water extracted organic matter (WEOM) and SHS, which has been observed in suspended particulate matter (SPM) and sediments [54]. [PERSON] et al. [54] reported the WEOM EEM component (C2/C3) ratios were 0.69 \(\pm\) 0.03 for sediment and 1.15 \(\pm\) 0.04 for SPM. The C2/C3 ratios had a positive correlation with the HIX. The C2 is located at E\({}_{\rm x}\)/E\({}_{\rm m}\) = 270/460 nm and C3 is located at E\({}_{\rm x}\)/E\({}_{\rm m}\) = 220/340 nm, which are located at regions V and II, respectively.