Endocrine disruptor compounds (EDCs) were defined by the World Health Organization as an exogenous substance, or mixture of substance, that have capacity to alter any function of endocrine system, causing an adverse effect on an organism, their progeny or on the population. Human sex steroid and pharmaceutical compound are considered as the most important members of EDCs, because could be responsible for several adverse effects on aquatic organisms at very low amounts (ng/L). The main source of these hormones is the discharge of treated municipal wastewater into water bodies. Both presence and the biological activity of them have been detected in water bodies especially in Europe, North America and Asia. However, the information available from South America is still very limited, mainly because there are not appropriate and sensitive methodologies to determine and quantify the hormonal activity. In this sense, this project is highly significant to the EDCs field, and specially could be a big regional impact to, because there are not enough data on the hormonal activity of these types of EDCs in Latin America. Additionally, from my Ph.D. experiments, we have evidence that these chemicals are causing adverse effects on fish populations, with a potential impact on the local fish farming economy. Thus, the present project will include the quantification of EDCs in my research, and I will be able to better evaluate the risk of the chemicals in the water bodies of Argentina.