Rutgers professor conducts study on long-term effects of oil spills
A shift in microbes caused by an unconventional oil and gas wastewater spill requires further study, according to a Rutgers professor's research.
The study, led by Nicole Fahrenfeld, a professor in the Department of Civil and Environmental Engineering, examined water and sediment from the nearby Wolfcreek in West Virginia.
Unconventional oil and gas production is when deep wells extract shale gas, coal bed methane or oil from tight rock formations through methods like hydraulic fracturing, Fahrenfeld said.
The spill in West Virginia happened at a site that disposes of the wastewater used at such facilities, Fahrenfeld said. It is not clear where the spill originated, but an injection well and settling ponds are located on the disposal site.
Wastewater is a combination of the materials that are pumped into the ground and natural materials that flow back when the wastewater is extracted, Fahrenfeld said. The chemistry team found these deep formation natural materials in the surface water near the spill — a most unnatural place for them.
One of the goals of the study was to determine if the biocides added to the wastewater were creating an environment where resistant bacteria are being selected, Fahrenfeld said.
Biocides are an additive used to prevent certain bacteria from clogging the wells, Fahrenfeld said.
Past studies have suggested that high levels of antibiotic resistance from the environment are linked to clinical infections, she said.
“You see a shift in the types of resistance there but there wasn’t an increase in resistance downstream,” Fahrenfeld said.
The study found over 40 resistance genes downstream from the disposal site, she said. By comparison, municipal wastewater — or everything that goes down a home drain — contains around twice as many resistance genes.
This research helped to identify what types of impact to expect from wastewater spills, Fahrenfeld said. This study will serve as the foundation for future efforts to treat and remediate wastewater spill sites.
“This spill is really starting to provide evidence that we are seeing the potential for microbial community change as a result of inputs of wastewater,” said Adam Mumford, a Rutgers alumnus and Mendenhall post-doctoral research fellow at the U.S. Geological Survey.
A potential marker of unconventional oil and gas produced wastewater is the ratio of Strontium-87 to Strontium-86, he said. These ratios suggested inputs of oil and gas wastewater were present in the stream water tested.
Elevated levels of radium were also found in the sediment downstream from the spill, Mumford said. While the levels were not great enough to cause concern, they suggested that there was a release of wastewater from the nearby facility.
A larger concern surrounding these microbial shifts is their effect on the nitrogen cycle, Mumford said. If microbial nitrogen cycling is disrupted, more nitrogen could be carried downstream where algal blooms can form, depleting the water's oxygen content.
Microbial communities are the base of the food chain and they drive the degradation of organics in a spill event, Mumford said.
The degradation of organics can mobilize metals into the ground, Mumford said. Understanding this process will be a key factor in future studies.
He said this study shows that microbial communities can change in the wake of wastewater spills. More research is required to understand the effect of these changes and how prevalent these changes are at other spill sites.
Students interested in learning more about the research that the U.S. Geological Survey (USGS) is conducting on the effects of wastewater spills can search for the USGS Toxic Substances Hydrology Program, “fate and effects of wastes from unconventional oil and gas development,” Mumford said.
Kenneth Kurtulik is a junior in the School of Arts and Sciences. He is a contributing writer for The Daily Targum.