## 3 Results and Discussions
### EDC Removal  
The influence of light, oxygen, and the presence of microalgae on EDC removal rates was studied for each contaminant. As shown in Figure 3a-c, parabens do not exhibit a representative abiotic degradation (LO and O experiments). However, the presence of microalgae (LOM experiments) enhanced the removal rates of these compounds, resulting in complete elimination within 7 days for both microalga species, exhibiting excellent performance for the degradation of these contaminants. These results agree with those observed by other authors. In this sense, a high MeP degradation efficiency using _C. vulgaris_ was reported, achieving the removal of 1 ppm of MeP within 2 days [67]. Furthermore, the complete removal of MeP and PrP, starting at 47.4 and 3.8 ng/L, respectively, was achieved within 7 days using C. _reinhardtii_, _S. obliquus_, _C. pyrenoidosis_, and _C. vulgaris_, separately [52]. Regarding BP degradation, similar high removal efficiencies were observed regardless of the type of experiment, as shown in Figure 3d. Thus, the efficiencies of BP removal in the LOM experiments on day 7 were 86% and 62% for _Scenedesmus_ sp. and _C. vulgaris_,  
Figure 2: Phosphate (brown cross) and ammonium (blue diamond) removal by (**a**) _Scenedesmus_ sp. and (**b**) _C. vulgaris_ in the presence of EDCs. Error bars represent \(\pm\) standard error of the mean (\(n=3\)). respectively, slightly lower than the ones obtained in the O and LO experiments (91% and 95%, respectively). These results suggest that the primary degradation pathway for this compound is most likely abiotic. No differences in removal rates were observed when comparing the O and LO experiments. Therefore, light does not significantly affect the elimination of BP, reaching only 20% removal within 7 days, as demonstrated in the Supplementary Material Section (Figure S1), which presents the results of the L experiments. Consequently, BP degradation may involve oxidation due to the presence of oxygen. Previous studies propose that the principal reactive oxygen species (ROS) involved in the photo-transformation of BP-3 are hydroxyl radicals (OH-) and superoxide radicals (-O\({}_{2}\)) [77]. In addition, other research hypothesised that BP may be degraded naturally when it is present in water in low concentrations [78]. Figure 3: EDC removal: O experiments (purple down triangle), LO experiments (red triangle), and LOM experiments with _Scenedesmus_ sp. (green circle) or with _C. vulgaris_ (orange square): (**a**) MeP, (**b**) PrP, (**c**) BuP, (**d**) BP (**e**) BPA, and (**f**) E removal. Experiments were conducted for 7 days. Error bars represent \(\pm\) standard error of the mean (\(n=3\)). BPA degradation is shown in Figure 3e. This contaminant was removed in abiotic conditions (O and LO experiments) by 20%, which agrees with the results previously reported [55]. In addition, the photodegradation (L experiment) of BPA was negligible, as depicted in Figure S1 (Supplementary Material). BPA removal increased significantly from the first day in the LOM experiment with _Scenedesmus_ sp. In contrast, significant BPA elimination in the LOM experiment with _C. vulgaris_ was observed from day 4 onwards, coinciding with its exponential growth phase and the decrease in ammonium and phosphate levels, as shown in Figures 1a and 2b, respectively. By the end of the 7 days, both _Scenedesmus_ sp. and _C. vulgaris_ achieved high BPA removal efficiencies, reaching 82% and 90%, respectively. These results are aligned with previous studies, such as the removal rate of 96% for BPA within 90 h using a consortium of Chlorophyceae-class microalgae and cyanobacteria, using a starting initial BPA concentration of 10 ppb [79]. On the other hand, [PERSON] et al. (2009) reported a degradation of BPA of nearly 92% within 16 days using _Stephanodiscus hantzschii_ in a medium containing 1 ppm of this contaminant [80].