The research focuses on environmental problems caused by improper handling of hazardous materials and wastes from major mining activities in the Amazon, especially the informal gold held in a small scale in the area of the lower Napo [1]. Our purpose is to identify the presence of mercury in the stock from fish consumption and its confirmation in the Napo River, we are also working on prevention to improve the quality of human life while raising awareness of the need for ongoing monitoring of the environment to improve and protect the lives of the residents of Santa Clotilde - Mazan and other exposed areas. The research is applied - descriptive, cross-sectional unexperimental design [2]. The study area is located in the Napo region of Loreto, has four seasons: (Mazan, Nuevo Libertad, San Luis, Santa Clotilde). Was considered to evaluate water and fish,from the river Napo. The quantificat...