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Show COLLEGE OF MINES & EARTH SCIENCES INDERGRADUATE RESEARCH ABSTRACTS ENVIRONMENTAL IMPACT OF GOLD MINING IN EL ORO, ECUADOR Christopher Tingey (William P. Johnson) Department of Geology and Geophysics University of Utah A study of contaminants in water and biota from artisanal and small-scale gold mining was conducted in El Oro District in southern Ecuador. The pH, dissolved oxygen, temperature, conductivity and alkalinity were tested in the field for surface and groundwater. Colialert was used to detect total coliforms and E. Coli. Water samples were collected and sent to the University of Utah where analyses performed included Cold Vapor Atomic Fluorescence Spectrophotometry (CVAFS) for total mercury (THg) and methyl mercury (MeHg) concentrations, Ion Chromatography (IC) for major anion concentrations, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for trace element concentrations, and Gas Chromatography (GC) after vacuum extraction for SF6 concentrations to determine groundwater age. Human hair and toenails, and cooked and raw seafood were sampled and analyzed using CVAFS for THg in the hair and seafood and ICP-MS for trace elements in the toenails. Results were compared to NOAA's Screening Quick Reference Table (SQuiRTs) for Inorganics in Water. Groundwater wells exhibited anoxic conditions; high alkalinities and higher conductivities with high concentrations of dissolved metals such as Al, Fe, and Mn. M n was found above SQuiRTs levels in all wells. Rivers downstream of the mining had higher conductivities and higher contaminant concentrations than upstream waters. Total coliforms were found in all but a few sites. E. Coli was found at a few downstream sites. THg concentrations were below SQuiRTs levels in all water with some anomalies. MeHg was low in all water samples. THg was high (453 ppb) in one fish from the Rio Gala. THg was highest in human hair from people living near the Rio Gala. Groundwater ages had a range of about 16 to 60 years. Future areas of research include mercury in downstream fish, high dissolved metals in groundwater, and health effects of M n in humans. Christopher Tingey William P. Johnson |