ABSTRACT
Anionic surfactant linear alkylbenzene sulphonate [LAS] was measured in water samples from three polluted areas. The highest concentrations of LAS were found in Lake Maryute, while Abu-Quir represented the intermediate area. Idku Lake proved to have the lowest concentration. It has been confirmed that the distribution of LAS in the water samples depended upon the studied areas, seasons and depths. The results of fish bio-toxicity showed that the LC[50]-96h.was 125 mg/l. The behavioural responses of the fish exposed to OMO was found to be identical to the effect of hypoxia, which points out to a similar mechanism of toxicity. On the other hand, fish exposed to sublethal concentrations of OMO exhibited a significant increase in the metabolic rate, which indicates a disturbance in carbohydrate metabolism