The objective of this study is to reveal the spatial and temporal variations of surface water quality in this part of the River Nile with respect to heavy metals pioneerution. Seventeen parameters in total were monitored at seven sites on a monthly basis from October 2013 to September 2014. The dataset was treated using the tools of univariate and multivariate statistical analyses. Cluster analysis showed three different groups of similarity between the sampling sites reflecting the variability in physicochemical characteristics and pollution levels of the study area. Six PCs factors were identified as responsible for the data structure explaining 91 % of the total variance. These were eutrophication factor (23.2 %), physicochemical factor (20.6 %), nutrients (16.3 %) and three additional factors, affected by alkalinity and heavy metals, recorded variance less than 15 % each. Also, the heavy metals pollution index (HPI) revealed that most of the calculated values were below the critical index limit of 100. However, two higher values (124.89 and 133.11) were calculated at sites V and VI during summer due to the temperature and increased run-off in the river system.
The monitoring of selected physicochemical parameters and chemical composition of water was conducted in 2017-2018 in the Lubrzanka river and the Cedzyna reservoir (Swietokrzyskie Mountains, Poland). The results indicate that the impact of reservoir on the quality of river water depends on natural characteristics of the catchment as well as on the present anthropogenic pressure. Retention of water in the reservoir caused seasonally diversified changes in analysed parameters, including an increase in water temperature, retention of major ions, nutrients and trace elements. Further research is needed to assess the risk of contamination of lower course of the river with metals deposited in reservoir’s bottom sediments.