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Show consistency and did not include all the parameters that are, or can be, measured currently. Since the causeway was constructed, and after 1966 when UGS began its chemical monitoring program, there has not been great change noted in the lake's chemistry. There has been a slight decline in potassium, magnesium and sulfate over time, but this is probably more attributable to the dissolution of sodium chloride from earlier precipitated sodium chloride than anything else. From 1966 ( and probably from 1959- 60 when the causeway was first constructed), the south arm of the lake was density- stratified. The lower layer of brine was of greater density than the upper layer. It was also dirty and contained considerable dissolved hydrogen sulfide gas. Because of this, heavy metals such as copper, iron, lead etc. that entered the lower, dense layer of brine were precipitated as metal sulfides. Because of this condition, the heavy- metal content of the lake remained very low during the above period of time. The lake was " self- cleaning" with respect to heavy metals. After disappearing in 1991 the dense layer is forming again. The ability to accurately determine the concentration of heavy metals in the highly- saline waters of GSL is a problem. One of the first real attempts to do this was reported by Tayler, Hutchinson and Muir of KCC in 1977. The only other public analyses that have been done are by the Utah Health Department, using standard analytical methods. Whether these methods are accurate for the high salinities found in GSL is questionable, especially for those analyses done years ago. Selenium bioconcentrates and could pose biological concerns for some GSL organisms. More information is needed about lake chemistry and the effects of trace elements in this unique aquatic system. DWQ does not see any water quality problems in GSL. Financial resources to establish numerical water quality standards are very limited, since available resources must be focused on high priority problems where impairments to stream uses are known, and ameliorations are required by law and funded. Also, many variables would need to be considered due to the chemically complex nature of the lake. Funding with partners and assistance from the Legislature would be necessary to initiate this effort. However, DNR would like to see research continue and will coordinate with DWQ and others in conducting research to better understand and monitor impacts to the lake and its resources. Numerical standards would help with enforcement and would also be effective in protecting water quality. Sewage treatment facilities are heavily controlled except for nitrogen and phosphorous. These nutrients would need to impair a beneficial use to require their costly removal from effluent. Since this issue is site- specific, much monitoring would be required. Best science would be needed to convince industry that removal would be necessary. There are no current problems. Ammonia toxicity is controlled and total dissolved solids is not a concern at this time. 296 |