Environmental Studies on Qalla Drainage Network (Lake Maruit), Using Aquatic Organisms as Bioindicators to Assess Levels of Pollution in it

Abstract

Lake Maruit is one of the four northern Delta lakes and it has special economic, social, tourist and security importance. The lake receives water form several drains and canals, it also receives most of the drainage effluents from Alexandria city. The majority of these effluents primary-treated wastewater and that causes deterioration in quality of water within the lake. Polluted water discharged into Lake Maruit caused sharp decrease in dissolved oxygen especially in the main basin due to highly organic nutrient loads coming from Qalla Drain. Qalla Drain network consists of seven branched drains, which flow and end into Lake Maruit main basin, and its water mix with discharge of East Alexandria Drainage System. East Treatment Plant (ETP) performed primary treatment for wastewater from the eastern portion of Alexandria and discharge in Qalla Drain network. The present investigation aims to study the impacts of different pollution sources on Qalla Drain network – Lake Maruit, via; water quality, metals accumulation in aquatic plants and sediments. Also, aquatic biota; phytoplankton, zooplakton and benthos, and their densities, diversity indices were identified. Statistical correlations and significance analysis between water, sediments, aquatic plants and biota were calculated. Pollution indicators and pollution bioindicators were assessed in the present study.