Impact of wastewater discharge diversion on some heavy metals content in Alexandria coast

ABSTRACT

Alexandria is the second largest city in Egypt and includes about 40% of the nation's industry. In the past, Alexandria city was discharging its wastewater either into the Mediterranean Sea along the city beaches or into Lake Maryut. In 1993, these outlets were closed except two main outlets at Qayet-Bey and EL-Mex Bay. The diverted wastewater is treated primarily and discharged into the sea at EL-Mex Bay. In the mean time, Environment Law 4/1994 prohibited all polluting establishments to discharge untreated wastes, which may cause pollution, along the Egyptian sea shores. The present work aims at assessing the improvement in the levels of some heavy metals in Alexandria coastal water after the diversion and the execution of Environment Law 4/1994 The study concluded that Abou-Qir water, and to a less extent Qayet-Bey water, was characterized by high averages of dissolved Cu, Zn, Pb, and Cr. El-Agamy Bay water sustained the highest levels of Cd, Co, and Cr. Qayet-bey water represented the highest Ni average. Qayet-Bey water sustained the highest levels of particulate Cu, Zn, and to a less extent Co, Ni, and Cr. El-Agamy water contained the highest levels of both dissolved and particulate Cd. Contrary to the case of dissolved form, spring and to a less extent summer achieved the highest concentration of particulate Zn, Cd, and Ni. The results displayed that dissolved forms of most studied metals were higher in concentration than particulate ones. Zn and Cr, on the other hand, were found in particulate form to be slightly higher than those in dissolved forms. The presence of heavy metals in considerable levels in all the studied sites indicates that Alexandria coast is still subjected to the polluting land-based sources. The study suggested some recommendations to improve the situation including industries should be enforced to treat their wastewater to comply with Law 4/1994, environmental impact assessment should be done for the new activities, continuous monitoring of the water quality of the beaches, and fishing from polluted areas should be prohibited