Tracing Creosote Contamination Through Slag Waste in a Hyper-Alkaline Environment, Chicago, Illinois

The Calumet area of southeastern Chicago remains a legacy to industrialization and industrial blight. This area contained wetlands which were filled in with waste—especially slag waste—to make the area suitable for building. The slag not only creates heterogeneous underlying geology, but also produces a hyper-alkaline environment where the pH of the groundwater has been recorded as high as 13.3 and surface water precipitates calcium carbonate sediment. This complicated hydrogeological system also creates a unique environment for microorganisms specifically adapted to the hyper-alkaline environment. On the adjacent property is a decommissioned coking plant; creosotes, coke, and coal lie openly on uncovered ground. As hydrocarbons weather, depending on their original chemical composition, they will degrade into characteristic polycyclic aromatic hydrocarbons (PAHs). The goal of this research is to identify PAHs present in the nearby surface waters and groundwaters through use of GC/MS to determine if these organic compounds are influencing the alkaline environment. By comparing the ratios of certain target PAHs present, the forensic source of the parent material may be determined and potentially determine if they are the source of organic carbon in the adjacent alkaline sites. As remediation efforts are currently occurring in the area, understanding the geochemistry, weathering and decomposition, and distribution of known contaminants is vital for effective local clean-up. PAHs can be hazardous and toxic to both humans and the environment, and thus serve as a target contaminant for remediation efforts. However, PAHs may also serve as energy sources for the unique microorganisms in the area. Investigating the geochemistry of this site is critical to ongoing research of the unusual microbiology and groundwater patterns in the area, as well as providing information that could be used in current and future remediation projects.