Sunday October 18, 2020
The extraction of crude oil and natural gas through fracking is controversial – also because of the consequences for the environment. Researchers are now reporting increased radiation around boreholes. That could endanger the health of residents.
Scientists have found elevated levels of radioactive particles in the vicinity of fracking wells in the United States. 100 additional boreholes at a distance of up to 20 kilometers are connected in model calculations with an increase of 0.024 millibecquerels per cubic meter of air. This is an order of magnitude that could potentially lead to health problems in humans, writes a group led by Petros Koutrakis from Harvard University in Boston “Nature Communications” magazine.
Since the early 2000s, the extraction of oil and natural gas through fracking has seen a boom. In order to extract oil from strata of rock, water is pressed in at high pressure to create cracks in the rock. Compared to conventional oil and gas production, large amounts of wastewater are generated. In addition, more soil is extracted because most such oil reservoirs are drilled at an angle – while with conventional oil extraction vertical holes are almost always drilled.
“The influence of unconventional oil and gas production on the radioactivity of ambient particles is not really understood,” the researchers write. To track down this influence, they used a database in which 1.5 million boreholes are recorded, as well as data from Radnet, a nationwide network in the USA for monitoring environmental radiation. In total, they analyzed more than 320,000 measurements of radioactive particles on 157 Radnet monitors in the period from 2001 to 2017. Koutrakis and colleagues used computer models to relate the boreholes to the measured values, taking into account the wind direction.
Larger amounts of drill core material
Radioactive particles come to the surface with every type of oil and gas production. When uranium-238 decays, gaseous radon-222 is formed. Its decay products combine with dust particles in the air through various processes. With an increase of 0.024 millibecquerels per cubic meter of air for an additional 100 boreholes, the calculated value for fracking production of oil and gas is considerably higher than that for conventional production with less than 0.004 millibecquerels. This applies to a radius of 20 kilometers around the boreholes, further away the radiation decreases rapidly.
The researchers attribute the increased radioactivity in unconventional oil and gas production mainly to the larger amounts of drill core material and the large amounts of wastewater. According to the researchers, the earth from the boreholes is not classified as hazardous waste by the US environmental agency Epa and can be used by drilling companies for various purposes.
Even if the increase in radiation values compared to the national average radiation value of 0.35 millibecquerel per cubic meter of air may appear to be quite small, the researchers assume that there will be consequences for the population in the vicinity of the boreholes: “Particle-bound radon decay products continue to ionize after inhalation Radiation free and can therefore trigger systemic oxidative stress and inflammation even at the levels observed in this study, “they write.