## 3 Results
### Removal of PCP and Nutrients from Contaminated Water by CWs Microcosms  
Plants of all systems showed some decrease in their vitality (by visual inspection) along the 8 weeks of experiment. PCP concentration in water from Ribeira de Joane and CWs effluents of control systems was always below detection limit (\(<\)4 \(\times\) 10\({}^{-5}\) ug\(\cdot\)L\({}^{-1}\)). In CW effluents of the doped systems PCP was always detected, concentrations varying between 2.5 and 13 ug\(\cdot\)L\({}^{-1}\) (Table 2). Removals varied between 87% and 98% (Figure 2), being significantly higher (\(p<0.05\)) in the first two weeks and statistically identical (\(p>0.05\)) in the following weeks. No PCP was detected in initial plant root bed substrate (T0) nor in plant root bed substrate from control systems at the end of the experiment (T8), with concentrations below the detection limit (<0.030 ng:g\({}^{-1}\)). In plant roots bed substrate from doped systems, PCP was detected (20 \(\pm\) 9 ng:g\({}^{-1}\)) at the end of the experiment period (T8) indicating that the compound was retained in the CW systems without total degradation. Taking in consideration the amount of substrate in each microcosm (ca. 35 Kg), the amount of PCP introduced along the 8 weeks in each microcosm (1.2 g of PCP) and the amount of PCP still presented in the treated water, the amount of PCP detected in the substrate was ca. 66% of the PCP amount introduced in each CW system. To evaluate a possible effect of PCP in CWs performance, organic matter (through COD) and nutrients (NH\({}_{4}\)\({}^{+}\), NO\({}_{2}\)\({}^{-}\), NO\({}_{3}\)\({}^{-}\) and PO\({}_{4}\)\({}^{3-}\) ions) removals were determined. COD concentrations in water of Ribeira de Joane varied between 19 and 55 mg:L\({}^{-1}\) (Table 3). COD removal percentages varied between 3% and 35% in control systems and between 8% and 48% in doped systems. COD removal percentages varied through time but no significant difference in COD removal percentages were observed (\(p>0.05\)) between control and doped systems, except in week two. Therefore, the presence of PCP did not interfere with the removal efficiency of the CWs systems. The NH\({}_{4}\)\({}^{+}\) concentrations in CWs influent varied between 18 and 84 umol:L\({}^{-1}\) (Table S2). The NH\({}_{4}\)\({}^{+}\) removal percentage in the systems was above 85%, except in week one of control with a removal percentage of 68 (\(\pm\)37)% (Figure 3). There were no significant differences between control and doped systems removal percentages (\(p>0.05\)). The presence of PCP did not interfere with the removal capacity of CWs for this nutrient. The NO\({}_{2}\)\({}^{-}\) concentrations varied between 2.2 and 26.8 umol:L\({}^{-1}\) in influent of CWs (Table S2). In both  
Figure 2: Removal percentage (%, mean and standard deviation, \(n=3\)) of PCP in CWs, irrigated for eight weeks with Ribeira de Joane water doped with 100 ug:L\({}^{-1}\) of PCP per week. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Week**} & \multirow{2}{*}{
\begin{tabular}{c} **CW Influent** \\ **(mg:L\({}^{-1}\))** \\ \end{tabular} } & \multicolumn{4}{c}{**CW Effluent**} \\ \cline{2-6}  & & **Control** & **(mg:L\({}^{-1}\))** & **\% of Removal** & **Doped** & **(mg:L\({}^{-1}\))** & **\% of Removal** \\ \hline
1 & 23 & \(22\pm 6\) & \(3\pm 25\) & \(15\pm 3\) & \(35\pm 15\) \\
2 & 42 & \(35\pm 1\) & \(16\pm 3\) & \(39\pm 1\) & \(8\pm 2\) \\
3 & 55 & \(36\pm 4\) & \(35\pm 6\) & \(29\pm 1\) & \(48\pm 2\) \\
4 & 46 & \(39\pm 5\) & \(16\pm 10\) & \(36\pm 4\) & \(22\pm 8\) \\
5 & 28 & \(21\pm 5\) & \(26\pm 18\) & \(21\pm 2\) & \(24\pm 5\) \\
6 & 22 & \(27\pm 3\) & n.r. & \(30\pm 1\) & n.r. \\
7 & 22 & \(16\pm 2\) & \(29\pm 9\) & \(19\pm 7\) & \(14\pm 32\) \\
8 & 19 & \(24\pm 4\) & n.r. & \(26\pm 8\) & n.r. \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Concentration of COD (mg:L\({}^{-1}\) water) in CWs influents and effluent (mean \(\pm\) standard deviation, \(n=3\)) and percentage of removal (%, mean \(\pm\) standard deviation, \(n=3\)) for eight weeks. n.r.