الفهرس 
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Abstract
The aim of the work is to study the ecological features and pollution status of Idku Lake to aid decision makers with important database. This can be achieved within the following objectives: Studing the floristic features of plant species distributed in open water of Idku Lake. Determination of physical and chemical characteristics of both water and sediments from different stations and its relation to plant life. Analysing of heavy metals (Fe, Co, Cr, Ni, Pb and Cd) in water and sediments for scouting their effect into the lake environment. Referring to the eutrophication status with the Idku Lake environment. Determination the phyto-accumulation efficiency of some aquatic species growing in Idku Lake The most dominant species which were recorded almost during summer and winter seasons were Eichhornia crassipes, Echinochloa stagnina, Phragmites australis and Typha domingensis. Other hydrophytes were restricted to a particular sampling site, for example Azolla filiculoides, Lemna gibba and L. minor, Persicaria salicifolia, Potamogeton pectinatus and Saccharum spontaneum were recorded at stations in south part of Lake. It must be highlighted that, in winter at station 2, 3 and 11 not any hydrophyte species recorded. The life-forms of the species recorded in the present study are grouped under four types as follows: therophytes (one species = 5.26%), geophytes (7 species = 36.84%), hydrophytes (5 species = 26.32%) and helophytes (6 species = 31.58%). The floristic analysis of Idku Lake reveals that six species (29.4% of the total number of recorded species) are Cosmopolitan taxa. Other taxa are either palaetropical and pantropical (4 species = 23.5%, each), Mediterranean and Neotropical (two species = 11.8 %, each). The concentrations of Fe, Cd, Cr, Co, Ni and Pb (mg.kg-1 dry weight) were analyzed in tissues of the hydrophytes E. crassipes (free floating), E. stagnina, P. australis and T. domingensis (emergent hydrophytes) collected from north and south sectors along the Idku Lake in two seasons (summer and winter).. The results of the heavy metal analysis revealed that, the hydrophytes were enriched with Fe as the most abundant metal followed by Ni>Co>Cd>Pb>Cr. The E. crassipes (floating hydrophytes) had the highest accumulation for each of the heavy metals among the studied hydrophytes in seasonal mean concentration along the north and south sectors of Idku Lake. By applying this index (MAI) to our results for individual species, The MAI was found in the order of P. australis > E. crassipes T. domingensis > E. stagnina.