The ecological status of phytoplankton communities in relation to physico-chemical characteristics at the area between Esna and Delta Barrage with a distance of about 805 Km was studied. Also bioassay experiments were conducted to determine the effect of industrial wastewater of iron and steel factories at Helwan on growth, Chlorophyll a and Photosynthetic activity of one alga (Scenedesmus quadricauda) which represent one of the most dominant phytoplankton in the Nile River. The growth rate (counting & Chlorophyll a) was more sensitive than photosynthetic activity. A synergistic effect was found between the trace metals of the waste. The toxicity of the waste decreased gradually by time.