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Extraction of mineral resources produces different types of residues; sonic of them are prone to the release of potentially toxic elements (PTEs) such as arsenic (As) and lead (Pb). This research analyzes the spatial distribution of As and Pb produced by their dispersion from ancient mining residues to sediments located within the Cerro de San Pedro micro-basin which is situated in a semi-arid region. Previous studies have shown that a pile of waste generated by ancient mining activities. The so-called Patio Victoria (RPV), which represent a contamination source, that is characterized by the content of sulfides that have led to, the generation of acid drainage [1]42],[3]. However, its impact on stream sediments at the micro-basin level has not been evaluated in detail over a length of 12 km. The approach considered in the work includes the identification of three zones: i). Zone A, upstream of RPV, ii) Zone B adjacent to RPV and iii) Zone C, downstream of RPV. Results for total concentrations in the sediment samples taken along the main stream of the micro-basin, indicate that the lowest concentrations for Pb (399-689 mg/kg, median of 542 mg/kg) and As (76-200 mg/kg, median of 105 mg/kg) were identified in Zone A. While Zone B involves the most impacted sediments with high concentrations of Pb (858-7590 mg/kg, median of 4288 mg/kg) and As (140-1025 mg/kg, median of 409 mg/kg). The concentration values for Pb (1136-7317 mg/kg, median of 1469 mg/kg) and As (189-429 mg/kg, median of 296 mg/kg) in Zone C, represent dispersion of the contaminant source along the main stream. Considering Zone A as the reference, a trend in Pb is observed with an increase of 7.91 and 2.71 times for Zone B and Zone C respectively. In the case of As the increase in Zone B is 3.90 times and 2.83 times for zone C. There is a significant statistical correlation of As and Pb (r(2)=0.89), which are found in the sediments mainly as arsenopyrite and galena as primary minerals and jarosite, anglesite, cerusite and iron oxides as secondary minerals. Results from this investigation indicate there is a potential impact of these pollutants on superficial and groundwater quality.