Characterisation of Nile and drinking water quality by chemical and cluster analysis.

Nile- and drinking water samples were collected from several locations between Aswan city and Cairo before and during the flood. Short-time activation analysis was applied to determine the concentrations of Al, Ca, Cl, F, K, Mg, Na and V, while Ba, Cr, Co, Fe, Hf, Rb, Sb, Sc and Zn were determined by irradiating the samples for 20 h at a neutron flux of 1.8 x 10(12) cm-2 s-1. The values of dissolved oxygen, nitrate, sulphate, orthophosphate, organic matter and the pH were determined by applying the standard methods. All data were examined statistically, and classified using cluster analysis technique. The results show that the concentrations of the major and trace elements in drinking water are higher compared with their levels in Nile water. This indicates that the water pumped from the Nile for use as drinking water is mixed with underground water before supplying. It has also been found that the concentrations of nitrate and phosphate in Nile water are significantly higher in Aswan than in those taken from the lower parts of the Nile. Cluster analysis proved to be an ideal technique for classifying these types of samples according to their sampling time and sites.