Marble runoff

Sulfur deposition and subsequent remobilization by incident rain for a limestone surface differs from that exhibited by a marble surface. This difference may be the result of larger porosity values of limestone compared to marble. Larger limestone porosity adsorbs a larger portion of incident rain than marble. Thus, fewer low-rain events occur for limestone. Where small rain-amount data are available for both limestone and marble, excess sulfate values consistently are lower for limestone runoff than for marble runoff. This observation suggests that limestone surface-accumulated sulfate is less mobile than marble surface-accumulated sulfate. 

Figure 13-9 Measured calcium in acid rain runoff from marble stone (which is largely CaC03) roughly increases as [H ] in the rain...

Not all mine drainage or natural runoff from rock outcrops are acidic, even when extensive sulfide oxidation is present. Synthetic cyanide solutions, which are often used to extract gold and other metals from ores, can greatly increase the alkalinity of mining wastes and neutralize sulfuric acid (Craw et al., 1999). In other cases, the sulfuric acid is effectively neutralized by alkaline soils, limestones, dolostones, marbles, shams, or other carbonate-rich rocks (Pfeifer et al., 2004, 219 Razo et al., 2004 Lee, Lee and Lee, 2001, 491 Mendoza et al., 2006). Reactions between calcium carbonate and sulfuric acid may precipitate gypsum (CaS04 2H20). 

Vorosmarty, C. J., K. Sharma, B. Fekete, A. H. Copeland, J. Holden, J. Marble, and J. A. Lough. 1997a. "The storage and aging of continental runoff in large reservoir systems of the world." Ambio 26 210-19. 

In this paper, we describe an onsite weathering experiment designed to identify acid-rain increased dissolution of carbonate rock. This experiment is based on the measurement of the change in rainfall-runoff composition from the interaction of a rock surface with incident acid rain 2. The experiment involves conducting long-term exposures of two commercially and culturally important calcium carbonate dimension stones (i.e., Indiana Limestone (commercial name for Salem Limestone) and Vermont Marble (commercial name for Shelburne Marble)) (3-5). This technique appears to give a direct measurement of the chemical dissolution of carbonate rock from the combined reactions of wet and dry deposition. Preliminary results from the initial months of onsite operation are presented to illustrate the technique. 

Approximately one liter of rainfall-runoff solution was collected from each of three experimental racks following rainfall events. Limestone and marble reference rocks were in two of the racks a third rack without a rock was used as a control (hereinafter referred to as a blank sample). Runoff volume, specific conductance, and pH measurements were determined at the exposure site as soon as possible after collection, typically within a few hours. Samples then were filtered through a 0.45-micrometer pore size membrane filter, placed in a clean polyethlyene bottle, and sent to the U.S. Geological Survey laboratory in Denver, Colorado, for chemical analysis. Sample preparation, analytical procedures, and laboratory quality-control protocols are described by Skougstad et al. (6). 

Reddy, M. M. Werner, M. Chemical analysis of samples from a rainfall-runoff experiment using limestone and marble at Research Triangle Park, North Carolina," U.S. Geological Survey Open-File Report 85-630. 

Emphasis in the field tests of stone briquettes is on the long-term damage suffered by exposed marble and limestone. Because the pH variations for the existing test sites are principally variations between one rain and the next rather than from site to site, the separation of the pH effect cannot presently be achieved (except possibly in runoff chemistry on individual rains). The annual... 

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