TRACING CREOSOTE CONTAMINATION THROUGH SLAG WASTE IN A HYPER-ALKALINE ENVIRONMENT, CHICAGO, ILLINOIS

The Calumet area of southeastern Chicago is a legacy to both industrialization and industrial blight. This area contained wetlands which were filled in with waste—especially slag—to make it suitable for development. The slag not only creates a heterogeneous underlying geology, but also produces a hyper-alkaline environment where the pH of the groundwater has been recorded as high as 13.3, surface water precipitates calcium carbonate sediment, and creates a unique and rare microbial environment. At an adjacent property is a decommissioned coking plant where creosotes, coke, and coal lie openly on the ground. As hydrocarbons weather, they degrade into characteristic polycyclic aromatic hydrocarbons (PAHs), unique to their original chemical composition. The goal of this research is to identify PAHs present in the nearby surface and groundwaters through use of gas chromatography/mass spectrometry (GC/MS) and to perform hydrocarbon forensic fingerprinting to determine if these organic compounds are influencing the alkaline environment. By comparing the ratios of target PAHs present to known compound profiles as well as suspected parent compounds from the site, the source of organic carbon in the adjacent alkaline sites may be identified. Microbial communities will be characterized by creation of a 16s DNA library, their carbon utilization patterns in Biolog Ecoplates, and random amplified DNA fingerprinting. As remediation efforts continue, understanding the geochemistry, weathering and decomposition, microbiology, and distribution of known contaminants is vital for effective local clean-up. PAHs, toxic to both humans and the environment, often serve as a target contaminant for remediation efforts. However, PAHs may also provide energy sources for the unique microorganisms present within the hyper-alkaline ecosystem. 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 descriptive data in current and future remediation projects.