Abstract:
The Hydrodrome, covering area of 5.04 km2 and average depth of 2.11 m, became polluted in recent years from the feeding contaminated Nile water. Surface water samples were collected monthly from this lake for studying seasonal distribution of Total Dissolved Zinc (TDZn), Total Suspended Matter (TSM) and Total Particulate Zinc (TPZn). The high amounts of TSM affected the distribution of TDZn. The behavior of Zn was generally governed with pH variations, influencing adsorption/desorption processes. The relative increase in TDZn in the lake compared with earlier data illustrates the effects of heavy metal pollution in recent years. The maximum average TDZn value at the location of breeding ducks coincided possibly with the erosion factors working on the large over floating metallic constructions built for this activity. The large amounts of organic matter derived from duck wastes containing TDZn participate in the increase in TDZn through phytoplankton recycling. The zonal distribution of TSM in the lake was limited. The feeding canal seemed to be not the main source of TSM, confirming existence of another source of TSM for the lake. The TSM peaks in spring and summer prove the biogenic TSM origin. It seemed that most of Zn in the lake, especially the inorganic forms, reached its water via anthropogenic sources and TPZn dominated the TDZn. A positive regression equation existed between TSM and TPZn; TSM = 24.483 ± 4.27 + 0.04 ± 0.02 TPZn (r = 0.354, p < 0.013). This illustrates that the bulk of TSM was composed of TPZn plus other contributors. The seasonal TPZn peak in April in the lake and its feeding waters increased the annual mean• concentration for the lake. The very high TPZn scored in April in front of the feeding canal reflected these spring peaks and mostly resulted from garbage wastes and letter dumped into the uncovered feeding canal.
