Artisanal gold mining is a major economic activity in Chami, Mauritania, but its reliance on elemental mercury (Hg) for amalgamation raises concerns about environmental contamination. This study investigates the spatial distribution, concentration, and potential sources of Hg in soils and process waters surrounding the Chami gold processing site. During a field campaign, 30 soil samples and 9 water samples were collected from processing areas and nearby boreholes. Soil samples were analyzed using aqua regia digestion followed by ICP-AES, while water samples were assessed using the DMA-80 Direct Mercury Analyzer. Mercury concentrations in soils ranged from 1 to 133 ppm, with elevated levels observed near processing residues. Water samples also exhibited detectable Hg, particularly in process ponds (109,06 mg/l). Pollution indices (PI) and geo-accumulation indices (Igeo) revealed moderate to high contamination, highlighting the significant influence of anthropogenic sources. Spatial analysis indicated that tailings and effluent discharge points are the primary contributors to Hg enrichment in the environment. These findings demonstrate that Hg from artisanal gold mining accumulates in soils and waters of Chami, posing potential ecological and human health risks. The study provides essential baseline data for monitoring and developing mitigation strategies, and contributes to understanding Hg dynamics in arid ASGM-impacted regions where data remain scarce.