Determination of free CO2 in emergent groundwaters using a commercial beverage carbonation meter

Abstract

Keywords:Dissolved carbon dioxide (CO 2 ) Groundwater Alkalinity Carbonate Springs Mine water s u m m a r y Dissolved CO 2 in groundwater is frequently supersaturated relative to its equilibrium with atmospheric partial pressure and will degas when it is conveyed to the surface. Estimates of dissolved CO 2 concentrations can vary widely between different hydrochemical facies because they have different sources of error (e.g., rapid degassing, low alkalinity, non-carbonate alkalinity). We sampled 60 natural spring and mine waters using a beverage industry carbonation meter, which measures dissolved CO 2 based on temperature and pressure changes as the sample volume is expanded. Using a modified field protocol, the meter was found to be highly accurate in the range 0.2-35 mM CO 2 . The meter provided rapid, accurate and precise measurements of dissolved CO 2 in natural waters for a range of hydrochemical facies. Dissolved CO 2 concentrations measured in the field with the carbonation meter were similar to CO 2 determined using the pH-alkalinity approach, but provided immediate results and avoided errors from alkalinity and pH determination. The portability and ease of use of the carbonation meter in the field made it well-suited to sampling in difficult terrain. The carbonation meter has proven useful in the study of aquatic systems where CO 2 degassing drives geochemical changes that result in surficial mineral precipitation and deposition, such as tufa, travertine and mine drainage deposits.

Isotopic evidence of enhanced carbonate dissolution at a coal mine drainage site in Allegheny County, Pennsylvania, USA

“…Field Gran titrations were conducted with a Hach digital titrator (Hach Co., Loveland, CO). Dissolved CO 2 was measured with a CarboQC carbonation meter (Anton Paar GmbH, Graz, Austria), which uses a multiple volume expansion method (Vesper and Edenborn, 2012). For groundwater sampling, each well was purged following the EPA Code 540/S-95/504 through a hose line (Puls and Barcelona, 1996).…”

Potential Impacts of Induced Bank Filtration on Surface Water Quality: A Conceptual Framework for Future Research

“…In tropical and temperate lakes, CO 2 supersaturation is dependent on groundwater CO 2 coming from weathering of minerals [176]. Groundwater in general often contains at least 35 times higher concentrations of CO 2 than lakes [177,178], up to 400 times higher in some cases [179,180].…”

Determining in situ pH values of pressurised fluids using stable carbon isotope techniques

“…If the pH value of the same fluid is measured at atmospheric conditions, CO 2 will be stripped from the fluid due to degassing triggered by a decrease in surrounding pressure. This would consequently result in an increased pH value at the surface and therefore the obtained results are often not representative for original fluid conditions (Vesper and Edenborn, 2012).…”