科研之友
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摘要
Long-term storage of S(0) blocks poses a contamination risk to both groundwater and surface water as the oxidation of S(0) to H(2)SO(4) creates drainage waters with low pH and elevated SO(4)(2-) concentrations. Because the presence of O(2) in the S(0) blocks is a primary control on S(0) oxidation, rates of atmospheric gas migration into the blocks can be used to quantify S(0) oxidation rates. Using in situ measurements and a tracer experiment combined with laboratory diffusion experiments, we determined that transport analysis of multiple gas species is required to quantify O(2) fluxes into a S(0) block. Advection, created by O(2) consumption within the block, accounted for 21% of the total O(2) influx and considerably increased H(2)SO(4) production in the block above that attributed to O(2) diffusion. While barometric pumping of the fracture porosity in the upper 8 m was probably occurring, its overall effect on O(2) influx was determined to be negligible. Quantification of O(2) and CO(2) fluxes was necessary to explain the direction and magnitude of N(2) concentration gradients that develop in the block, despite the fact that N(2) was nonreactive. Our findings should be widely applicable because the construction method of S(0) blocks is standard throughout the world.
- 出版日期2010-5
