Water 5

USGS is evaluating whether the cause of increasing salinity is drawdown causing eastern flow of more mineralized water from the aquifer’s western end or if drawdown is resulting in greater leakage from the bottom of the overlying Springfield Plateau Aquifer (Pope et al., 2009), where mineralized water may be concentrated and drawn through the confining aquitard (Pope et al., 2009). USGS thought nutrient concentrations were small Figure 16), the depth concentration profiles for well water were chemically uniform, and that most of the observed salinity was due to east west traditional salinity change within the Ozark Aquifer (Lower). The metals data at the end of Figure 15 was meant to eliminate leakage into wells from mining sources. Some local wells close to mining operations showed evidence of contamination. This USGS report also has a rather convincing section on groundwater flow path and well analysis based on multi isotopic analysis. A result of this analysis was that the water quality was measurably degraded on the western end of the study area due to salinity transition. There seemed to be measured caution at using the word “degrading”.

The author thought that there was a very interesting history and discussion of water quality and geochemistry in the Ozark Aquifer from this report (Pope et al., 2009) and thought it would make a nice conclusion to this section: ”The largest dissolved-solids concentrations determined during this investigation probably are related to a general transition from freshwater to saline water in the Ozark aquifer in an east-to-west trend across the study area (Macfarlane and Hathaway, 1987; Imes and Davis, 1991; Imes and Emmett, 1994). This increase in dissolved solids is a vestige of the original connate “formation” water (Jorgensen and others, 1996) and may reach".