Long-Term Affects of Wastewater in Disposal Sites from Fracking
How it works
This article discusses a study done at Penn state into the long-term affects of wastewater in disposal sites from fracking. In 2011, water and sediment downstream of fracking disposal sites was discovered to still contain unsafe levels of some chemicals, despite the water being treated, and had become radioactive. This had contaminated drinking water and aquatic life in the river, causing die-off of some present species. Due to this discovery, fracking wastewater was no longer treated and released back into the rivers, but instead recycled. However, it has been determined there are still some effects from the 3-year period (2008-2011) when over 2.9 billion liters of the “treated wastewater was being pumped back out into rivers.
Mussels filter water, so the shells of mussels can act as a record over time of water quality in which they are present. Researchers gathered mussels from the affected river, both downstream and upstream, as well as a control group of mussels from a river that had no history of fracking wastewater disposal, then removed the shell. The shells were drilled and powder collected from each layer. The researchers were looking for two things: isotopes of oxygen and strontium. Oxygen isotopes could be used to determine the year and season the shell layer developed, and strontium because it is a chemical present in the fracking wastewater that can have negative affects at certain levels. Both these isotopes have a distinct signature and thus were chosen as the focus chemicals of the study.
How it works
Significantly higher levels of strontium were found in the shells downstream of the wastewater plant than in the shells upstream and from unaffected rivers. There was also little immediate reduction shown in the shell chemistry after removal of wastewater in 2011 (timing having been calculated from the oxygen isotopes present in the shell layers) suggesting that sediment in the river may also still contain the chemicals from wastewater even after the wastewater was no longer being put into the river.
In my opinion, this study highlights the fact that was might not understand fully the repercussions of some actions related to fracking and other types of oil and gas development. In the study they noted that the wastewater that was being released between 2008 and 2011 had been treated and released in accordance with the National Pollutant Discharge Elimination System, which is a program under the Clean Water Act, allowing for that kind of thing. Despite that, there were still harmful levels of pollutant in the water which will likely have an affect for a much longer period of time than initially thought. Like the article also states, the presence of high chemical levels in mussels can also cause contamination to animals that use mussels as a food source, spreading the effect even further. I believe this study is also a good indicator that aquatic life can be used to record changes in river environments, and the article even says that mussels could be used in the future to investigate the possibility of wastewater seepage at other treatment plants.