Background and Aim: Given the increasing use of detergents and the problems of water pollution caused by the release of wastewater containing large amounts of detergents in recent decades, this study aimed to investigate the concentration and health and ecological risk assessment of linear alkylbenzene sulfonate (LAS) as the most important detergent composition in Ekbatan Dam is Hamedan, Materials and Methods: 31 sampling stations from Ekbatan dam reservoir and Inlet Rivers to Ekbatan dam and overflow dam (Abshineh dam) selected for water sampling, Parameters such as water temperature, pH, EC, TDS, DO and ORP was measured at the sampling site, LAS adsorption was reading through a spectrophotometer (WTW 660) at 650 nm, The pollutant concentration was calculated through the equation of the calibration curve, Results: The results showed the measured LAS concentration in the range of 0, 01-1, 4 mg / L, The results of the Spearman correlation test between LAS and water quality factors showed a positive significant relationship between LAS with salinity, TDS and EC at 0, 01 level and a negative relationship between LAS and DO at 0, 05 levels, The results of the health risk assessment of LAS showed no risk in different age groups, The results of the comparison of LAS concentration with surfactant discharge standard in surface water and irrigation and agricultural applications in Iran showed that the concentration of LAS is below the permissible level (1, 5 mg / L) for discharge into surface water, However, in terms of use for agricultural and irrigation purposes, the LAS value at 7 stations was higher than the permissible level (0, 5 mg / L), Conclusion: The results of this study showed that Ekbatan dam and rivers entering the dam are exposed to mild wastewater as a result of human activities, Therefore, it is necessary to take effective and preventive activities to control and reduce pollutants entering this valuable dam,