2009 Issue

13 their oxidation, and increases the total-dissolved solids content of the mine water. The quality of themine-water effluent is also influenced to a somewhat smaller degree by coal preparation (i.e., washing, sizing and cleaning) which also results in potential impacts to groundwater via infiltration of leachate from coal-processing waste piles. A variety of minerals other than coal are extracted currently in Utah. Meth- odologies employed include solution mining, surface mining of ore bodies, underground extraction, dump or heap leaching, and brine recovery using solar evaporation. The use of cyanide solutions or sulfuric acid to recover gold and uraniumby heap leaching creates a high potential for groundwater contamination if the leach pads are constructed without underlying leak detection systems and protective liners. Oil and Gas Exploration and Production Sources: An important part of Utah’s economy is the process of exploration for and production of oil and gas. Many abandoned production wells, if not sealed properly, ultimately can be a source of groundwater contamination. Exploration wells have significant potential for groundwater contamination with the contaminants entering the groundwater systembelow the water table. Primarily, this is a consequence of installing insufficient surface casing or inadequately cemented casing in the well bore. Presently in Utah the Division of Oil, Gas, and Mining administers Class II wells under the partially delegated Underground Injection Control (UIC) program. These wells are used to reinject production water. Solid-Waste Sources: Migrating plumes of contaminated groundwater, containing material leached from land-disposal sites of solid-waste mate- rial, are an ever-increasing concern. Examples are garbage, manure, sludge, municipal, industrial, and abandoned waste sites. If these wastes are soluble, precipitation can infiltrate and dissolve material from these wastes, causing groundwater contamination. A significant reduction has occurred in the number of operating landfills accepting municipal wastes. Other Surface Impoundments: Though rarely reported, many industrial sites have surface impoundments that contaminate groundwater to the point where treatment is required. EPA found that the second largest groundwater contamination source in the nation is holding ponds and lagoons over water- table aquifers. In order to minimize adverse effects to human health from contaminated groundwater, sewage lagoons must be kept at a pre-deter- mined distance fromwells used for drinking water. Two serious groundwater contaminants commonly found in sewage waste water are nitrogen, as am- monia or nitrate, and bacteria. Viruses and bacteria that cause waterborne diseases are a serious and common groundwater contamination problem near sewage lagoons. Wastewater containing large amounts of dissolved material, much which is toxic, is often found in industrial lagoons. EPA found that the vast majority of lagoons, believed to be impermeable or leaking at a controlled or reduce rate, still leak excessively. Design For Protection Utah’s groundwater quality protection rule was designed to achieve certain goals and recognize certain realities concerning the sources and prevention of groundwater contamination. In summary the regulations em- phasize prevention of groundwater contamination; utilize widely accepted, scientifically based standards as a basis for measurement of water quality; afford greater protection for high quality groundwater; provide an early Salt Lake • Measure selenium flux to and from sediment and atmosphere (primarily volatilization) • Define the transfer of selenium from water and diet to brine shrimp Each project was a unique collaboration between the Steering Committee, Science Panel and investigators. Data and observations from all of these projects were documented in individual project reports and integrated into a quantitative model and synthesis report that is available on DWQ’s project website, http://www.deq. utah.gov/Issues/GSL_WQSC/index.htm. The quantitative model was developed from the data collected from Great Salt Lake to describe the transfer of selenium from water and sediment up through the food web and into bird eggs. The model al- lows the user to estimate diet and egg selenium concentrations from an assumed waterborne selenium concentration and vice versa. Resulting waterborne, diet, and egg concentrations are listed and plotted upon egg and diet toxicity curves to illustrate potential effects of selenium on egg hatchability. This model was a key tool in facilitating the discussion and evaluation of alternative water quality standards. Results and Recommendations As with any research program, it seems more new questions about the lake’s characteristics were identified the more we probed the details of its inner workings. The lake appears to be successfully managing exist- ing levels of selenium without adverse effects, however how it is doing so remains somewhat of a mystery. While many questions were left unanswered, the Science Panel agreed with the investigators findings andmade its recommendations to the Steering Committee. Subsequent discussions among Steering Committee members and later with the State Water Quality Board resulted in the following recommendations and water quality standard: ™ The water quality standard should be a tissue-based standard, SELENIUM WATER — continued from page 10 based upon the selenium concentration found in the eggs of birds using the open waters of Great Salt Lake. A bird egg concentration of 12 μg Se/kg was eventually selected as the water quality standard by the State Water Quality Board. š For implementation of a tissue-based standard, the waterborne concentration of selenium associated with the water quality standard should be derived from the quantitative model developed as part of the program. › A unique tiered approach to implementation of the standard was developed. This approach was developed to address uncertainty in the data and model, the bioaccumulative nature of selenium, the need to incorporate both waterborne and tissue-based selenium concentrations, and the desire to proactively protect and manage the water quality of Great Salt Lake. If selenium concentrations are observed to rise, the tiered approach facilitates the assessment of trends, continuing improvement of the quantitative model and its uncertainties, continuous assessment of the water quality standard, and the identification and implementation of management actions to protect the water quality of the lake. This effort resulted not only in the first site-specific numeric water qual- ity criteria for Great Salt Lake, it is also the nation’s first site-specific, tissue based selenium water quality standard established for the protection of aquatic wildlife. Many eyes in Utah and the country are now focused on this great resource and how it will be managed. Much was learned about the lake and about what we do not know about the lake. Most importantly, all involved walked away with an increased appreciation for the unique and complex nature of the lake and the successful underpinnings for ongoing collaboration in managing one of our State’s jewels. Mr. DenBleyker, is a Senior Project Manager and Operations Leader for CH2M HILL’s Salt Lake City water business group. He received his B.S. degree fromCalvin College and M.S. degree from the University of Iowa continued on page 14