A sulfur-isotope mixing model to trace leachate from pressurized fluidized bed combustion byproducts in an abandoned-coal-mine setting

✍ Scribed by R.J Haefner

• Book ID: 104135653
• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 184 KB
• Volume: 80
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/s0016-2361(00)00161-7

✦ Synopsis

Approximately 125 tons per acre of dry pressurized ¯uidized bed combustion (PFBC) byproducts were applied during reclamation to a 7acre abandoned coal mine in eastern Ohio, USA. The purpose of the application was to raise the pH of the soil and allow for re-establishment of vegetation. To trace leachate derived from the PFBC byproduct, sulfur-isotope ratios (d 34 S) were measured from solid-phase materials and water samples. The d 34 S value for the PFBC byproduct ranged from 14.6 to 14.8½. Spoil and aquifer-material samples had d 34 S values less than 13.2½. Unsaturated-zone waters within the PFBC byproduct application area had isotope signatures representative of the byproduct, whereas similar waters from outside the application area had signatures representative of the spoil. A sulfur-isotope-mixing model indicated that as much as 75% of the sulfate in the unsaturated-zone waters in the application area was derived from PFBC byproduct leachate. Sulfate concentrations in ground water increased after reclamation (from 1,110 to 2,100 mg/l in upgradient wells and from 1,770 to 1,880 mg/l in downgradient wells); however, the sulfur-isotope data indicate that sulfate in ground water was derived from oxidation of pyrite in the mine spoil, not by the leaching of PFBC byproduct.