## 3 Results and Discussion
### Untargeted Analysis
#### 3.1.1 Hydrocarbons  
After a first screening in full scan mode, a more sensitive and selective analysis was performed in SIM mode. The ions monitored were at 57, 71 and 85 \(m/z\), which are characteristics of linear hydrocarbons. Procedural blanks were analyzed, and their contribution in hydrocarbons was subtracted from the samples. For each sequence of analyses, an alkanes standard mixture (C10-C40, concentration 1 mg L\({}^{-1}\)) was employed to verify retention times and normalize chromatographic signals in order to perform a comparative analysis of the extracts obtained from different samplers. Results obtained in the first monitoring, reported in Figure 1, did not show significant differences among the hydrocarbons sampled in the tank (P1 and P2; P3 and P4) and in the treated water (T1 and T2; T3 and T4). Furthermore, results obtained for the samplings I and II showed a comparable profile regarding the presence of the homologous series of even n-alkanes of petrogenic origin [21]; therefore, no seasonal trend appears evident. \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Compound**} & **LOD** & **LOQ** & **LOD** & **LOQ** & **Intra-Day Precision** & \multirow{2}{*}{**Accuracy (\%)**} \\  & **(\(\mu\)g L\({}^{-1}\))** & **(\(\mu\)g L\({}^{-1}\))** & **(\(\mu\)g/POCIS)** & **(\(\mu\)g/POCIS)** & **(RSD\%)** & \\ \hline EE2 & 1 & 5 & 2 & 10 & 2.9 & 100.7 \(\pm\) 6.7 \\ MEF & 0.05 & 0.5 & 0.1 & 1 & 3.8 & 102.1 \(\pm\) 6.7 \\ FFOA & 0.01 & 0.1 & 0.02 & 0.2 & 1.8 & 105.6 \(\pm\) 12.8 \\ PFOS & 0.01 & 0.05 & 0.02 & 0.1 & 1.5 & 107.4 \(\pm\) 12.2 \\ E2 & 1 & 5 & 2 & 10 & 5.6 & 101.9 \(\pm\) 10.8 \\ BPA & 0.05 & 0.5 & 0.1 & 1 & 7.5 & 99.2 \(\pm\) 7.4 \\ CAF & 0.01 & 0.5 & 0.02 & 1 & 2.6 & 97.5 \(\pm\) 5.3 \\ CBZ & 0.01 & 0.05 & 0.02 & 0.1 & 3.4 & 106.9 \(\pm\) 15.6 \\ DIC & 0.05 & 0.5 & 0.1 & 1 & 2.7 & 101.9 \(\pm\) 5.5 \\ E1 & 0.5 & 1 & 1 & 2 & 4.5 & 98.9 \(\pm\) 8.1 \\ OD-PABA & 0.01 & 0.05 & 0.02 & 0.1 & 7.0 & 101.2 \(\pm\) 3.3 \\ EHMC & 0.01 & 0.5 & 0.02 & 1 & 2.0 & 105.0 \(\pm\) 15.6 \\ GBZ & 0.05 & 0.1 & 0.1 & 0.2 & 2.2 & 99.8 \(\pm\) 9.0 \\ IBD & 0.5 & 2 & 1 & 4 & 5.4 & 97.5 \(\pm\) 6.6 \\ BP-3 & 0.01 & 0.5 & 0.02 & 1 & 1.3 & 103.0 \(\pm\) 6.8 \\ NAP & 0.05 & 0.1 & 0.1 & 0.2 & 6.0 & 105.7 \(\pm\) 13.8 \\ OC & 0.01 & 1.0 & 0.02 & 2 & 4.4 & 103.5 \(\pm\) 18.9 \\ TCS & 0.1 & 1.0 & 0.2 & 2 & 2.9 & 103.5 \(\pm\) 5.6 \\ \hline \end{tabular}
\end{table} 
Table 1: Limits of detection and quantitation of the monitored emerging pollutants in solution (\(\mu\)g L\({}^{-1}\)) and in the POCIS sampler (ng/POCIS), intra-day precision and accuracy. In sampling II of the first monitoring, an evaluation of the treatment process was carried out by analyzing the POCIS deployed in supply water and treated water (Figure 2). Figure 1: Results obtained from the semi-quantitative analysis of hydrocarbons (chain length: 10–28 C atoms) in treated water (T1 and T2 in orange) and shark tank water (P1 and P2 in blue) in sampling I (**A**). Results obtained from the semi-quantitative analysis of hydrocarbons (chain length: 10–28 C atoms) in treated water (T3 and T4 in yellow) and shark tank water (P3 and P4 in green) in sampling II (**B**). As/Ast represents the ratio between the hydrocarbon peak areas in the sample and in the reference standard. Figure 2: Results obtained from the semi-quantitative analysis of hydrocarbons (chain length: 12–28 C atoms) in supply water (S1 and S2 in light blue) and treated water (T3 and T4 in red) in sampling II. As/Ast represents the ratio between the hydrocarbon peak areas in the sample and in the reference standard. T3 and T4 extracts showed a good decrease in hydrocarbon concentration, especially for short chain alkanes (between C12 and C16). This result suggests that sand filtration has a lower impact on long chain analytes or that shorter hydrocarbons tend to undergo degradation onto the filter [22]. Water treatment efficiency was further investigated in the second monitoring. Linear alkanes from C10 to C40 were found in S3, S4 and S5 and in T5, T6 and T7 water extracts.