# Preliminary Analysis of the Water Quality Status in an Urban Mediterranean River
## 4 Discussion
Citizen engagement is important to monitor and improve river water quality effectively and achieve the goal of a progressive reduction in discharges from the point and non-point pollution sources, coupled with knowledge on factors that are related to urban riverscapes and recreational uses [27]. We conducted this preliminary study examining the Kifisos river to analyze its water quality status, including physicochemical parameters, nutrients, _E. coli_ and polycyclic aromatic hydrocarbons concentrations. The results indicated the significant water quality degradation of the river, particularly at downstream stations, between the stations K 17 and K Ekv, probably triggered by urban runoff, illegal sewage and industrial waste disposal. K 17 and K 5 are the stations with the worse quality status, which was expected due to their close proximity to industrial areas. Even the upstream station (K MD) illustrated a poor or bad physicochemical water quality status in more than 50% of the sampling efforts. An existing study [28] for the Kifisos river revealed similar influence by anthropogenic activities regarding major elements (nitrate and phosphate concentrations). Another study [29] revealed that the Kifisos river is highly polluted and ranked the river's quality as very poor regarding species diversity. In the current study, the average _E. coli_ concentration was significantly high at all stations, characterizing the water as bad quality, while the total polycyclic aromatic hydrocarbons (TPAHs) results indicated the existence of significant pollution. More specifically, the TPAHs and TH concentrations detected along the river (particularly in K 5 site) indicated the presence of pollutants originating from petroleum sources. Our results regarding the levels of the TPAHs and THs are similar to other studies in urban areas [16; 30]. High TPAHs and THs values should most likely be attributed to road runoff from heavy traffic highways adjacent to the river. Point source pollution from industries located along the route of the river should also be examined. Moreover, other manmade chemicals, such as heavy metals and pesticides, can also impact water quality and aquatic ecosystems. Therefore, monitoring should be done in conjunction with other water quality assessments to provide a comprehensive evaluation of river health. All of the above indicate the necessity of continuous environmental monitoring at certain points of the river and legal investigations to identify the specific polluters in order to undertake the necessary restoration actions. In the future, a multi-pollutant modelling approach would help to better understand and manage water quality issues, since monthly sampling is unlikely to offer the necessary information for classifying the water quality status accurately [31]. These issues can be addressed by field-deployable water quality analyzers designed to continuously measure concentrations of pollutants in freshwater [32]. Switching to sustainable uses of freshwater resources is critical for minimizing land degradation and biodiversity loss [33]. From a water quality management perspective, it is evident that continuous environmental monitoring at certain points of the rivers is essential to reduce uncertainty in the results. High frequency samplings with the adoption of modern sensors can provide high frequency data [34] and substantially larger datasets to reduce uncertainty of pollution load estimates, particularly in urban rivers with multiple stressors, such as the Kifisos river [35].