## 3 Results and Discussion
### Microbiological Data
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Season**} & \multicolumn{2}{c}{**Total Coliforms (log\({}_{10}\) CFU/mL)**} & _Escherichia coli_ (log\({}_{10}\) CFU/mL) \\ \cline{2-6}  & **Inlet** & **Outlet** & **Inlet** & **Outlet** \\ \hline C1 & 5.1 \(\pm\) 0.5 & 3.4 \(\pm\) 0.5 & 2.7 \(\pm\) 0.6 & NC \\ H2 & 4.8 \(\pm\) 0.3 & 3.5 \(\pm\) 0.2 & 3.5 \(\pm\) 0.3 & 2.5 \(\pm\) 0.3 \\ C2 & 4.6 \(\pm\) 0.1 & 2.8 \(\pm\) 0.2 & 3.0 \(\pm\) 0.3 & NC \\ H3 & 5.1 \(\pm\) 0.6 & 2.8 \(\pm\) 0.6 & 2.9 \(\pm\) 0.3 & 2.3 \(\pm\) 0.5 \\ C3 & 4.3 \(\pm\) 0.3 & 2.7 \(\pm\) 0.1 & 3.1 \(\pm\) 0.3 & NC \\ \hline \hline \end{tabular}  
* NC: no viable counts.  
\end{table} 
Table 2: Total Coliforms and _Escherichia coli_ counts (log\({}_{10}\) CFU/mL) in CW inlet and outlet wastewater during the cold (C) and hot (H) seasons across three consecutive years (1, 2, 3). Values are presented as CFU Log\({}_{10}\) mean \(\pm\) standard error (n = 3–4 for each season). \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Season**}} & \multicolumn{2}{c}{**Total Coliforms (log\({}_{10}\) CFU/mL)**} & _Escherichia coli_ (log\({}_{10}\) CFU/mL) \\ \cline{2-11}  & **Inlet** & **Outlet** & **Inlet** & **Outlet** & **Inlet** & **Outlet** \\ \hline C1 & 5.1 \(\pm\) 0.5 & 3.4 \(\pm\) 0.5 & 2.7 \(\pm\) 0.6 & NC \\ H2 & 4.8 \(\pm\) 0.3 & 3.5 \(\pm\) 0.2 & 3.5 \(\pm\) 0.3 & 2.5 \(\pm\) 0.3 \\ C2 & 4.6 \(\pm\) 0.1 & 2.8 \(\pm\) 0.2 & 3.0 \(\pm\) 0.3 & NC \\ H3 & 5.1 \(\pm\) 0.6 & 2.8 \(\pm\) 0.6 & 2.9 \(\pm\) 0.3 & 2.3 \(\pm\) 0.5 \\ C3 & 4.3 \(\pm\) 0.3 & 2.7 \(\pm\) 0.1 & 3.1 \(\pm\) 0.3 & NC \\ \hline \hline \end{tabular}  
* NC: no viable counts.  
\end{table} 
Table 3: Enumeration of total coliforms, _Escherichia coli_, and total heterotrophic bacterial (HB) associated to plant roots (log\({}_{10}\) CFU/g fresh weight) and in the substrate (log\({}_{10}\) CFU/g wet soil) from the CW inlet and outlet zones, in cold (C) and hot (H) seasons across three consecutive years (1, 2, 3). Substrate- and root-associated total coliforms (CFU/g) in the inlet zone ranged between log\({}_{10}\) 4.5 (C1) and log\({}_{10}\) 6.6 (H2, H3) and between log\({}_{10}\) 5.1 (C1) and log\({}_{10}\) 6.8 (C2), respectively, while in the outlet zone counts varied from no viable cells in C2 to log\({}_{10}\) 5.7 in H3 both for substrate and roots. A similar trend was observed for _E. coli_ counts, which varied between log\({}_{10}\) 2.9 (C3) and log\({}_{10}\) 3.8 (C1) and between log\({}_{10}\) 3.5 (C2) and log\({}_{10}\) 4.9 (C1) in substrate and roots of inlet zone, respectively. In the outlet zone, _E. coli_ was only detected in samples corresponding to the hot season in the last two years (H2, H3). Contrary to what was observed in wastewater, season variations seemed to influence total coliforms and _E. coli_ prevalence in the substrate, as counts tended to be lower in cold seasons (C1, C2, C3) than in hot seasons (H2, H3). Of relevance, it has been noted that in relation to _E. coli_, no viable counts were attained for substrate and root in the three cold seasons. A generalized decrease of both bacterial groups from inlet to outlet of up to 2-3 log was observed, corroborating the results obtained for wastewater, suggesting the effectiveness of CW in removing bacterial pathogens. Moreover, the number of total coliforms and _E. coli_ associated with roots tended to be higher than in the substrate, in particular in the inlet zone, for all sampling campaigns, suggesting the active role of plants in the depruation mechanism of bacterial pathogens in the CW. Indeed, [PERSON] et al. [28] showed that 49% of the bacterial endophytes recovered from tissues of _C. flaccida_ plants growing in inlet and outlet zones of the same CW belonged to Enterobacteriaceae. Yet, a significant decline was observed in the number of enteric bacteria from the inlet (62%) to the outlet zone (38%). This is in line with the reduction of the number of total coliforms and _E. coli_ recorded in the outlet zone in this study.