## 4 Conclusions  
The results of the ecotoxicological tests confirmed that the raw effluent (RE) was extremely toxic; however, the treatment implemented by the textile industry clearly reduced the toxicity of the samples, although there was still a level of sublethal toxicity to _D. magna_. In addition to the sublethal toxicity, it can also maintain the eutrophication potential, as observed for the TE1 sample at the lowest concentrations. This motivate the need for an \"effectiveness of the treatment\" variable, which requires a more detailed assessment to understand which compounds cause the toxicity.  
The present results also emphasised the importance of the chemistry evaluation and the compliance with environmental protection laws and legal limits for wastewater discharges. However, this assessment alone is not enough because it does not provide enough information about the effects of pollutants on organisms in the ecosystem. Thus, the importance of including regulations regarding a battery of bioassays with different organisms is of the utmost importance since these effluents are complex mixtures and only biological species can allow the complete evaluation of their actual  
\begin{table}
\begin{tabular}{l c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**RE**} & \multicolumn{3}{c}{**TE1**} & \multicolumn{3}{c}{**TE2**} \\ \cline{2-10}  & **EC\% (\%)** & **EC\% (\%)** & **TU** & **EC\% (\%)** & **EC\% (\%)** & **TU** & **EC\% (\%)** & **EC\% (\%)** & **TU** \\ \hline _A. fischeri_ & 7.2 & 2.92 & 13.9 & NT & NT & \textless{1} & - & - & - \\  & (0.4–100.0) & (0.152–56) & & & & & & & & 98.5 \\ R. subcapitata & NT & 79.5 & \textless{1} & NT & NT & \textless{1} & NT & (96–100.3) & \textless{1} \\  & 95.7 & 74.9 & & & & & & & 82.9 & 75 & \\  & (91.8–99.6) & (69.2–80.7) & & & & & & & (81.7–84.1) & (73.6–77.4) & 1.22 \\  & & 76.8 & & & & & & & 80.4 & \\ L. minor (dry biomass) & NT & (65.8–87.8) & & & & & & & & (76.3–84.6) & \textless{1} \\ D. magna & 24.2 & & & & & & & & & (76.3–84.6) & \textless{1} \\ (immobilisation) & (22.2–26.4) & - & 4.14 & NT & - & \textless{1} & - & - & - \\  & 18.2 & 8.3 & & & & & & & & \\ D. magna (feeding) & (16.0–20.5) & (6.4–10.2) & 5.48 & & & & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 4: Values of TU (toxic units), EC\({}_{50}\) and EC\({}_{20}\), with 95% confidence limits inside brackets, for all tests performed with the treated effluent samples (TE1 and TE2) and the raw effluent sample (RE).  
hazard to the aquatic systems. Presently, many kits are available for these assays, which makes these evaluations possible on a routine basis.  
Conceptualisation, I.L. and R.P.; methodology, V.N. and I.L.; formal analysis, A.M.C.; effluent chemical analysis, T.R.-S.; writing original draft preparation, A.M.C. and V.N.; review and editing, V.N., I.L., T.R.-S. and R.P.; supervision, I.L. and R.P.; funding acquisition, R.P.  
This research was partially supported by the Strategic Funding of CIIMAR-UP (UID/Multi/04423/2013) through national funds provided by the Foundation for Science and Technology (FCT) and the European Regional Development Fund (ERDF), in the framework of the program PT2020. Financial support to CESAM (Centre for Environmental and Marine Studies) (UID/AMB/50017), from FCT/MEC (Ministry of Education and Science) through national funds (IF/00407/2013/CP1162/CT0023), and co-funding by the FEDER (European Regional Development Fund), within the PT2020 Partnership Agreement and Compete 2020 is acknowledged.  
The authors declare no conflict of interest.