Research Project

Native fish monitoring, food web dynamics, and heavy metal transportation in Southern Arizona’s aquatic ecosystems

Native fish in Arizona are impacted by numerous anthropogenic disruptions and are an imperiled fauna.  Aravaipa Canyon is one of Arizona’s last properly functioning aquatic ecosystems, which includes an assemblage of seven native fish, two of which (Meda fulgida and Tiaroga cobitis) are federally listed as endangered.  Although Aravaipa Creek is an intact aquatic system with high fish and macroinvertebrate biodiversity, it has still been impacted by human activity, in particular, mining activity.  It has long been recognized that mining activity and resulting mine wastes, including tailings, are an increasing problem, where acid leachate production in these tailings results in lower pH and increased solubility of toxic metals in ground and surface waters.  Aravaipa Creek is geographically close to two major past mining operations; the Klondyke smelter tailings and Grand Reef mine tailings.  The Klondyke tailings are several miles upstream of perennial Aravaipa Creek and are a past superfund site, where flooding releases elevated levels of lead and arsenic. In 2008, ADEQ attempted to remediate this site by capping the waste rock, to prevent further contamination of Aravaipa Creek and the surrounding area. Little attention has been given to the Grand Reef mine as a potential secondary point source for inorganic contaminants. Currently we are working with partners from the Bureau of Land Management, U.S. Fish and Wildlife Service, the Nature Conservancy and U of A (Department of Evolutionary Ecology and Biology, Department of Geosciences, and Department of Soil, Water and Environmental Sciences), to investigate and quantify the sources of contamination in Aravaipa Creek and the effects of the Klondyke remediation effort.  We also want to further examine impacts that that the Grand Reef mine may be having on aquatic biota in Aravaipa Creek. Of particular interest is fish and macroinvertebrate health, contamination location, mode of transportation of metals to the stream and transportation of heavy metals through the food web which may result in bioaccumulation or biomagnifications of key deleterious contaminants. We currently employ a suite of techniques, including heavy metal analysis (ALEC), lead, carbon, and nitrogen isotopes, and community structure analysis, to examine the effects of these two past mining sites on the aquatic ecosystem function of Aravaipa Canyon.

The Patagonia Mountains, Southeastern Arizona lie within a region of Laramide age porphyry copper and associated precious metals mineral deposits. Relatively small-scale base and precious metal mining dates back well over 100 years and to a limited degree continues today.  Metals extracted from the areas mines include copper, lead, zinc, gold, and silver. Most mines in this area have been inactive for decades; however, the exposed waste-rock, tailings, and mine-related discharges are still having impacts on the biota in the associated drainages.  Of particular interest is Flux Canyon/Alum Gulch and upper Harshaw Creek because heavy metal-laden, low pH water have been sampled from significant portions of their stream reaches as base flow and storm runoff.  Discharges from a  principal mine portal and in- stream springs associated with the World’s Fair mine fed directly into Alum Gulch, and in 2007 the Arizona Department of Environmental Quality (ADEQ) sited the U.S. Forest Service due to low pH (2.7 to 3.7) and metals impacts to the stream.  Since this time remediation efforts have taken place, removal of adjacent waste, tailings piles, and blocking flow from mine portal. However, low pH and elevated metal discharges continue and are periodically connected to Sonoita Creek and Patagonia Lake, and eventually reaches the Santa Cruz River during monsoon-related storm events.  Sonoita Creek has a rich native fish and aquatic macroinvertebrate communities, which are excellent indicators of water quality. We currently use a variety of techniques, including heavy metal analysis (ALEC); lead, carbon and nitrogen isotopes; and community structure analyses to examine macroinvertebrate and fish community structure alterations, food web disruption, and transportation of heavy metals through this community of aquatic organisms.

Funding Agencies: BLM, U.S. Fish and Wildlife, The Nature Conservancy, USGS, Forest Service

Princple Investigators: Peter Reinthal and Floyd Gray