Temporal and spatial variations of surface water quality in the Nile River of Damietta Region, Egypt

Temporal/spatial variations of surface
water quality were examined for the Nile River in
the Damietta region where it serves as the major
source of water for the inhabitants of Damietta
Governorate. A total of 32 water quality parameters
were monitored at six sampling sites for 12 months
from February 2016 to January 2017. Higher values of chemical oxygen demand (COD), biological
oxygen demand (BOD), heavy metals, and nutrients were observed upstream. About ~ 70% of the
total variance in observations was explained by fve
main infuences using factor analysis. The frst factor (24.6% of the variance) was indicative of the
mixed sources of natural and anthropogenic inputs.
The second (nutritional) and the third (organic) factors were mainly controlled by the discharges from
agricultural and domestic sources, respectively.
Human activities and natural processes controlled
the fourth and ffth factors. Only 11 parameters (K,
temperature, COD, HPC, total hardness, DO, NO2,
Na, TDS, Cl, and EC) were necessary for distinguishing temporal variations according to Discriminant analysis (DA). Seven parameters (BOD, PO4,SiO
3, Al, Turbidity, Fe, and Chlorophyll-a) were
the most important variables responsible for spatial
variations. Using the results we developed a water
quality index (WQI) using only those parameters
identifed as important. All water quality parameters were below the permissible limits except for
turbidity according to the World Health Organization standards, BOD and COD according to the
Egyptian regulations. The calculated WQI values
ranged between 12.73 and 33.73. According to
these values, the Nile River Damietta branch represents a good to an excellent source of drinking
water for entering secondary treatment.