Andrea Reither’s scientific contributions

This is the PowerPoint presentation that accompanied the paper - some of the images may be easier to read. J. Gusek

There is a potential for runoff to become polluted with sulfuric acid and metals (mostly iron) when the pyrite/sulfide rock weathers in road projects where Chattanooga shale and other pyrite-bearing or sulfide-bearing rock formations are exposed. As a part of surface water pollution management, the Tennessee Department of Transportation updated its standard operating procedure to create a new guidance document. A team of geologists and GIS experts developed a database to quickly identify projects that need to follow the new guideline to avoid impacts by highlighting zones of geologic formations known to contain pyrite or acidic pH-neutralizing rocks such as carbonates. Despite the implementation of best management practices, some residual acidic/metal runoff may occur. For these situations, BMPs from mining industry experience are applied, and may have reverse application in mine waste situations. TDOT's new guidelines are the most comprehensive construction-related acidic rock drainage BMPs of any state DOT.

When portions of the Chattanooga shale and other pyrite-bearing or sulfide-bearing rock formations are exposed in Tennessee Department of Transportation (TDOT) road projects, there is a potential for runoff to become polluted with sulfuric acid and metals (mostly iron) when the pyrite/sulfide rock weathers. As a part of surface water pollution management, TDOT recently updated its 18-year-old standard operating procedure (SOP) for dealing with this important issue to create a new guidance document. In the process, a team of geologists and GIS experts developed a GIS database of information that TDOT could use to quickly identify projects that might need to follow the new guideline to avoid impacts. This information includes zones of geologic formations known to contain pyrite and formations containing acidic pH-neutralizing rocks such as carbonates. The GIS database was also configured to not only receive the wealth of analytical data that TDOT has assembled over the past decade on pyrite-related road projects but to allow addition of new information in the future. The project team geochemists further compiled the latest research on pyritic rock characterization and testing and compared it to protocols found in TDOT's existing SOP. The new guideline document, building on years of TDOT's actual experience, was also based on mining industry experience in mitigating pyrite-derived impacts. It was recognized that despite the implementation of up-to-date Best Management Practices (BMPs), some residual acidic/metal runoff may occur. For these situations, the guideline provides passive treatment system (a.k.a. constructed wetland) BMPs, again based on mining industry derived experience. TDOT's new guidelines are the most comprehensive construction related acidic rock drainage BMPs of any state DOT.