Hydrogeochemistry of carbonate groundwaters of an urban area

Abstract

A comparison of the groundwater chemical data from the shallow dolomite aquifer of Northeastern Illinois Metropolitan Area (NIMA) from August 1972 through April 1973 with data collected 12–40 yr earlier indicates that concentrations of all ions have increased, the greatest increase occurring in the south‐eastern part of the area where the overburden is thinnest. The largest increases are 843, 142, and 91% in Cl−, SO42−, and Na+, respectively. However, the spatial distribution of the groundwater chemical types has remained the same with time. The groundwater was found to be apparently supersaturated with respect to calcite and dolomite; however, the two saturation indices were reduced by 20 and 30%, respectively, after considering the effect of ion pairings. The chemical character of the groundwater is controlled, among other factors, by the change of carbon dioxide content of the water along the groundwater flow path. A model for the solution of dolomite based on the standard equations for carbonate equilibrium is presented. The application of the model to the study area indicates that a variety of geologic conditions between the dolomite aquifer and the overlying glacial drift prevail in the area.

Long‐Term Trends in Chloride Concentrations in Shallow Aquifers near Chicago

“…A difficulty in determining temporal changes in ground water quality is the lack of long‐term chemical data and thus an understanding of how water quality has changed or is changing. Because of this, the literature on long‐term temporal variations in ground water quality is limited, especially in urban areas (Long and Saleem 1974; Gibb and O’Hearn 1980; Hull 1984; Montgomery et al 1987; Yee and Souza 1987; Spruill 1990; Broers and van der Grift 2004; Drake and Bauder 2005).…”

“…Increased water demand can put a strain on limited water sources, and many urban activities can degrade water quality. Urbanization has long been recognized as a threat to shallow ground water quality (e.g., Long and Saleem 1974; Eisen and Anderson 1979; Eckhardt and Stackelberg 1995; Bruce and McMahon 1996; Murray et al 2004). Contamination is often linked to land‐use changes and the presence of numerous pollutant sources such as landfills, sewage treatment plants, industrial effluents, septic systems, gasoline storage tanks, road runoff, and so forth.…”

Geochemistry of the Floridan aquifer system in Florida and in parts of Georgia, South Carolina, and Alabama

“…Many papers attempt to relate the total C02 dissolved in ground water to the C02 of the soil zone in recharge areas because of the effects C02 equilibria exert on both rock dissolution (for example, Thrailkill, 1968;Langmuir, 1971;Shuster and White, 1972;Long and Saleem, 1974;Drake and Wigley, 1975;Harmon and others, 1975 Trainer and Heath, 1976;Pitman, 1978) and the carbon isotope content of ground water (for example, Pearson and Hanshaw, 1970;Rightmire and Hanshaw, 1973;Deines and others, 1974;Fritz and others, 1978;Pearson and others, 1978;Rightmire, 1978). Drake and Wigley (1975) derived a general relation between soil PC02 and soil zone temperature which explained the PC02 in calcium-carbonate-saturated ground water that had evolved under essentially "closed system" conditions.…”

Temporal and spatial patterns of Cl- and Na+ concentrations and Cl/Na ratios in salted urban watersheds

“…This number is not fixed, of course, and can vary across the state. It has been shown that in a similar setting in a watershed in north eastern Illinois that a clear link to the influence of halite near surface water chemistry could not be established until dissolved Cl -and Na + concentrations were over 50 mg/L might be consider elevated (Long and Saleem, 1974). We considered for illustration purposes, 100 mg/L as representing Cl -concentrations that are clearly elevated from natural concentrations.…”