“…This parameter is positively correlated with SAR, Fe and Mn (R = 0.699, p < 0.05; Fe: R = 0.699, p < 0.05; Mn: R = 0.633, p < 0.05) and negatively correlated with NH 4 , NO 2 , Ca, Mg and Cl (NH 4 : R = −0.562, p < 0.05; NO 2 : R = −0.596, p < 0.05; Ca: R = −0.416, p < 0.05; Mg: R = −0.601, p < 0.05; Cl: R = −0.477, p < 0.05; see Table S3). As reported in other studies, BOD 5 is one of the parameters that is often responsible for surface waters not reaching the good potential ecological status [6,14,46,47]. In this study, high BOD 5 levels may be mainly correlated with the runoff of organic materials (vegetable matter), from intensive crops, which constitute almost 50% of land use around the basin (Figure 2).…”