The impact of a former small Pb-Zn mine in Hunan (China) was studied in terms of arsenic (As) and metals concentrations in water streams and sediments, and from the perspective of biogeochemistry of As. Three water streams were characterized, two from galleries and one seeping at the base of the mine waste rocks dump. Contrary to the water from galleries, this last stream was acidic and contained relatively high As concentration. High As levels were also found in sediments downstream of the mine drainage flowing from the first gallery. Diverse As(III)-oxidizing bacteria were enriched and isolated from the mine sediments, some presenting ability to grow at low pH or in autotrophic conditions.