A multi-disciplinary team at the Prairie Research Institute at the University of Illinois at Urbana-Champaign has developed a quick and inexpensive technique to screen for water contamination from fracking oil recovery operations.
The technique targets fluorescent compounds in the "produced" waters generated from oil extraction wells, meaning that a distinct marker for different companies could be introduced to fracking compounds that then could identify specific sources of any subsequent contamination.
Using fluorescence excitation-emission (EEM) spectroscopy, common oil contaminants such as benzene and polycyclic aromatic hydrocarbons (PAHs) can be detected at very low concentrations by fluorescence. Using an anti-corrosion agent commonly used for oil extraction wells, the team scanned fluorescence signals that are easily distinguishable from signals returned from naturally occurring organic matter.
The work was presented at the U of I's Institute for Sustainability, Energy, and Environment's 2015 Congress on Water last month. The collaborators are John Scott, senior chemist, and Nandakishore Rajagopalan associate director and the state of Illinois' Pollution Prevention Scientist, at the Illinois Sustainable Technology Center; Thomas Holm, groundwater geochemist at the Illinois State Water Survey; and Peter Berger, assistant geochemist at the Illinois State Geological Survey.
Characterizing "produced" waters from oil extraction using conventional laboratory methods can be time-consuming and expensive, according to Scott. The formulas for injection solutions are proprietary to each oil recovery firm so it is difficult to trace contaminants in surface water, groundwater, or drinking water back to the source.
This new approach offers the possibility that permitting authorities could require the addition of a fluorescent liquid - such as some food colorings or other non-toxic and environmentally friendly additives - to fracking waters to provide chemical markers that could settle contamination disputes for oil companies and home owners - and also improve the science of hydrology. A unique 'color,' added to the water pumped deep underground to release petrochemicals in rock, could offer evidence of contamination if it showed up in surrounding water supplies.
In addition to water monitoring applications, these methods could be utilized by the energy industry to assess the feasibility of water reuse and assist in troubleshooting leaks in current water recycling systems.
Seed funding for this project was obtained through the Prairie Research Institute Matching Research Awards Program.