Ecological Impacts of Mine Pollutants in Patagonia, Arizona: Studying the Effects of Heavy Metals on Aquatic Ecosystems

Abstract

Mine tailings pollute surrounding waterways with high levels of heavy metals leftover from mining and milling processes. In arid climates like Arizona, these pollutants are transported to surrounding environments and downstream via aeolian transport (wind), and via precipitation from seasonal storms like Arizona's monsoon season. Elemental analyses for invertebrates were conducted twice per year at 8 sites throughout 3 locations in Patagonia, Arizona. The sites were all downstream of a mine, and drained into Patagonia Lake. Elemental analyses for fish were conducted at Patagonia Lake with the same frequency. These were done for 12 heavy metals. Sufficient data was collected only for Dysticidae invertebrates at Alum Gulch, and as expected, our results showed higher levels of heavy metals at our sites post-monsoon season (with the exception of mercury and manganese). This increase in heavy metal concentrations can be attributed to transport by precipitation from monsoonal storms. Increases in heavy metal concentrations were also found for all 12 elements in fish of Patagonia Lake.