Hydrobiologia 340: 77-83, 1996. 1. M. Caffrey, P. R. F. Barrett, K. J. Murphy & P. M. Wade (eds), Management and Ecology of Freshwater Plants. @1996 Kluwer Academic Publishers. Printed in Belgium. 77 The impact of three industrial effluents on submerged aquatic plants in the River Nile, Egypt M. M. AliI & M. E. Soltan2 Department of Botanyl and Chemistry2, Faculty of Science at Aswan, Assiut University, Aswan 81528, Egypt I '", Key words: River Nile, industrial pollution, submerged macrophytes, canonical ordination Abstract The submerged vegetation growing in the drainage channels taking effluent from three factories (two processing sugar cane plus one producing chipboard or paper pulp; and one large fertilizer plant) into the River Nile in Upper Egypt, and in the river itself upstream and downstream of the discharge points, was studied during 1994. The main pollutants from the sugar cane factory effluents comprised organic matter, including carbohydrates; from the fertilizer plant ammonia was the principal pollutant. The study investigated the effect of these different pollutants on aquatic plant standing crop and distribution, in relation to physico-chemical characteristics of water and hydrosoil. In the effluent channels, dominated by large growths of sewage fungus, submerged vegetation was absent, although some emergent vegetation survived. In the most polluted river sites, up to 2 km downstream of discharge points, the flora was restricted to Potamogeton pectinatus L. Elsewhere in the river, a more diverse submerged flora was present, including Ceratophyllum demersum L. and Potamogeton crispus L. Introduction " ;; Pollution is generally associated with heavy industrial- isation and dense population and is one of the principal ecological problems of the River Nile system. Aquat- ic environment pollution comes from both natural and anthropogenic sources and occurs in many different forms: sediments, sewage, disease-causing agents, inorganic plant nutrients, organic compounds, inor- ganic chemicals, radioactive substances and thermal pollution. The four major sources of human induced water pollution are industry, domestic activities, ship- ping and agriculture. Factors affecting the distribution of submerged aquatic macrophyte communities in the Nile in Upper Egypt have been described by Ali (1992). This present study aims to detect the principal pollutants produced by three factories that discharge their effluents into the River Nile, and to describe the effect of these point- source pollutants on submerged aquatic macrophyte communities. Description of sites studied Effluents of three factories (two processing sugar cane and producing chipboard or paper pulp; and one large fertiliser plant) which discharge into the River Nile in Upper Egypt (Figure 1), were selected for study. The Edfu sugar cane (ESC) and paper pulp (EPP) factory, 100 km North of Aswan, discharges its effluents direct- ly into the Nile. The Kom Ombo sugar cane (KSC) and chipboard (KCB) factory, 45 km North of Aswan, discharges its effluents by way of an uncovered dis- charge channel that also receives leaching from the surrounding agricultural lands. The Aswan Kima fer- tilizer (AKF) factory, discharges its effluents into the River Nile through an uncovered channel that passes through the city and receives untreated domestic wastes (human and sewage wastes). Ammonium nitrate 34.8% (N concentration 99.8 %) is the main product of the fac- tory.