The environmental and health risks associated with fracking have drawn international attention, with some countries for it and others against it. While some governments, encouraged by oil and gas companies, try to implement this technique, researchers, communities and other governments base their opposition on studies that document the many risks and damages it causes. In reality, the problem is mainly economic and political, since currently the protection of the environment faces great interest and has a secondary place in the decisions of governments.
The study of the environmental impacts of drilling to obtain hydrocarbons through fracking has been a particularly difficult challenge due to the large number of factors that are largely unknown due to the poor quality and limited quantity of available data. However, the studies carried out to date, and the documented impacts on communities close to fracking, show that the effects and deterioration are real and inevitable.
Studies funded by industry and independent specialists indicate that there are inherent problems with fracking engineering that cannot be avoided with current materials and technologies; among them: are uncontrolled and unpredictable fracturing, induced seismicity, significant methane leaks, as well casing deterioration.
Although techniques are generally improving, the geology is sometimes unpredictable, so the appearance of fissures and the loss of toxic materials cannot be avoided.
While new evidence of the risks continues to be discovered and work is being done to better understand fracking and its negative consequences, there is no doubt that this technique has aroused much controversy and is challenging the interest and real capacity of governments to control damage through of regulatory mechanisms. And is that, although more and more is known about the short-term risks of fracking, its long-term risks continue to be ignored, which can be enormous.
The fracking process entails a large number of environmental effects, some of which are not yet fully characterized. They stand out among them:
In addition to these impacts, those related to the significant traffic of heavy vehicles to transport the extracted gas and the occupation of the territory for extraction must also be taken into account.
Fracking fluids. Very little is known about the environmental risks associated with the substances present in the fluids used to fracture the rock, which represent between 0.5 and 2 percent of the volume of those fluids. Any risk to the environment and human health associated with these fluids depends, to a large extent, on their composition; however, in the United States, federal legislation does not require fracking companies to disclose the substances they use, since most fluid additives are exempt from the regulations of the Safe Drinking Water Act, which has created a vacuum of information on the content, characteristics, concentration, and volumes of fluids that are injected into the ground during fracking operations and their return to the surface as wastewater.
As a result, regulators and the public in that country cannot assess the potential adverse impact of these fluids on the environment or public health. The situation is worse in countries that import the technique without obtaining information about its risks, since, in them, the regulations are usually far from what is necessary.
Although, due to various pressures and at the initiative of the government, the industry created the FracFocus database to collect data on the components of hydraulic fluids; Apart from the fact that participation in the said base is voluntary, the information will not include the chemical identity of the patented products; nor can it be determined whether the companies are reporting exactly the characteristics of what they apply in each well.
The hydraulic fracturing process consumes enormous amounts of water. Traditionally, massive fracking (MHF) uses between 4.5 and 13.2 million liters of water per well and, in large projects, up to 19 million liters per well. Additional water is needed when wells are re-fracked.
It has been estimated that the average single well operation requires between 9,000 and 29,000 cubic meters (9 to 29 million liters) of water over its lifetime. Even in countries with a temperate climate, this could cause problems in water availability and, in more arid areas, increase supply restrictions and water stress.
To meet the water needs for hydraulic fracturing, water is usually obtained from natural streams, municipal supplies, and industries such as hydroelectric power plants, all of which drastically reduce the availability of water for domestic and recreational uses.
It is important to highlight that the water used in fracking is lost to the hydrological cycle since a) it remains in the well, b) it is recycled for the fracking of new wells, or c) it is disposed of in deep wells to discard the waste. remnants of the operation. For any of these reasons, in addition to being contaminated, it is not available to recharge the aquifers.
During the process there are fracking fluid losses from the fracture channel into the surrounding permeable rock that, if left unchecked, can exceed 70 percent of the injected volume, damaging the matrix, causing undesirable fluid interactions, altering the fracture geometry, and reducing production efficiency.
Depending on the sources of information, it is estimated that the amount of fluid that returns to the surface along with the gas fluctuates between 15 and 70 percent. Additional amounts may return to the surface from abandoned wells or by other routes. Once the return flow has been restored, the water that was present in the subsurface can continue to flow to the surface and must be treated or disposed of.
Despite the measures that have been taken to prevent the substances used in fracking from reaching aquifers and other water deposits, there is evidence that this is not always possible and many aquifers have been contaminated.
Residual and return water. One of the most difficult problems to solve in this technique is how to store or dispose of wastewater, whose potential toxicity is difficult to assess because many fracking fluid additives are industrial secrets and their characteristics are unknown.
To date, there is no effective treatment for return water, which leaves it unusable for other uses and outside the hydrological cycle. To manage it, efforts have been made to isolate it and inject it into latrine wells, but this is not a solution, since it has been proven that these wells leak and have contaminated entire aquifers.
A 2011 study by the Massachusetts Institute of Technology (MIT) found evidence that, in some areas of the United States, natural gas (methane) is migrating into drinking water sources. Studies, also from 2011, by the Colorado School of Public Health and Duke University mentioned methane contamination of groundwater from the drilling process, which negatively affects water quality and, in extreme cases, can cause explosions.
Among the substances dissolved during the fracturing process, there are heavy metals, hydrocarbons, and radioactive elements that can present additional risks.
Methods for treating wastewater, (also known as flowback, return water, or wastewater), include subsurface injection, municipal water treatment plants, industrial wastewater treatment, and self-contained systems at exploitation and recycling zones to fracture new wells.
Return water recycling is a slow, complex, and not always efficient process; requires additional substances to be used and water can only be recycled up to a certain concentration of total dissolved solids. Some plants that treat this water cannot remove large amounts of dissolved solids, and such solids (salts, organics, heavy metals) in the fracking fluids can impede treatment.
An additional concern is that the oil obtained by this system may contain some of the substances used in hydraulic fracturing, which can accelerate the corrosion of rail tanks and pipelines in which it is transported, with the potential risk of contamination. generate leaks.
Radioactivity. In some cases of hydraulic fracturing, radioactive elements such as uranium, radium, radon, and thorium can be released from the rock and can rise to the surface with the returning fluid. This generates additional concerns about the presence of radioactivity in the fracking wastewater and its possible adverse impact on public health, since, as mentioned before, its recycling has limits.
Air emissions from the fracking process include methane leaks from wells and emissions from Diesel fuels or natural gas from equipment used in the process; for example, compressors, drilling rigs, pumps, etc.
Leaks from gas wells and pipelines can also contribute to air pollution and increase greenhouse gas emissions.
Methane leaks are estimated to be between 1 and 7 percent; the US Environmental Protection Agency (EPA) estimates the methane leak rate to be approximately 2.4 percent. Benzene, a potent carcinogen, has been identified in steam from evaporation wells, where fracking wastewater is often stored.
It is controversial whether natural gas produced by fracking causes more well-burner emissions than gas from conventional wells, but according to some studies, fracking generates more emissions due to the gas that is released during the drilling and preparation of wells, in addition to some returns to the surface of the gas associated with the fracking liquids.
A large number of vehicles are needed during the process (each good pad requires between 4,300 and 6,600 truck trips for machinery transport, cleaning, etc.), and the operations of the plant itself also cause air pollution. significant, especially by acid gases, hydrocarbons, and fine particles.
If the water needed for the process is transported by trucks, these can also contribute significant emissions to the air, especially particulates.
Gas emissions and their contribution to global warming. 90 percent of the emissions in the process of obtaining the gas are methane, although sulfur dioxide, nitrogen oxide, and volatile organic compounds are also emitted. Although the combustion of natural gas emits less carbon dioxide than other hydrocarbons, the entire process of its exploitation contributes to a greater extent to the acceleration of climate change due to methane leaks during its extraction, which can reach 8 percent of the total production of a well, which is more than what is generated in conventional gas extraction projects.
Methane is a greenhouse gas and its warming potential is greater than that of carbon dioxide, so the impact of shale gas extraction on climate change may exceed the use of coal as a fuel. On the other hand, depending on its treatment, well-burner emissions for fracking gas are 3.5 to 12 percent higher than for conventional gas.
To know the effect of fracking on climate change, it is crucial to quantify methane leaks into the atmosphere and question the fracking industry, which claims that they are less than 2 percent. For example, a recent study by the US National Oceanic and Atmospheric Administration and the University of Colorado at Boulder found that in the Denver-Julesburg basin, leakage was 4 percent, not including additional losses. the piping and distribution system, which is more than double what the industry acknowledges.
In the United States, the promoters of fracking argue that the extraction and use of this gas would allow the energy independence of the country and would reduce the burning of coal. However, according to a 2011 study by the United States Center for Atmospheric Research, unless leak rates of methane extracted by this technique can be kept below 2 percent in the future, the substitution of coal for this gas will not reduce the magnitude of climate change.
Drilling operations can cause severe degradation of the landscape due to the high occupation of the territory and, in addition, noise pollution as a result of daily operations that include vehicle traffic, in addition to the noise of the drilling itself, which can negatively affect nearby populations and local fauna due to habitat degradation. Desertification is another worrying environmental factor.
Routinely, fracking generates microseisms that can only be detected with highly sensitive instruments, but it can also cause major events that can be felt by nearby populations. If these small earthquakes trigger a fault, serious problems can arise. Faults, destabilized by the pressure to which they are subjected and the effect of earthquakes, can cause events of considerable magnitude. These microseisms are often used to map the vertical and horizontal extent of the fracture.
Because the industry cannot treat the large volumes of wastewater generated by fracking, it is common for it to use injection wells (also known as pit latrines) to dispose of contaminated water. The injection of these waters can destabilize geological faults and cause earthquakes.
Another of the dangers of fracking is the possibility that a dangerous failure generates, in turn, other dangers, such as the rupture of the good jacket or the contamination of the water table.
In Arkansas, Ohio, Oklahoma, Colorado, and Texas, regions without historical seismic activity, earthquakes greater than 3 degrees on the Richter scale have multiplied in recent years, whose epicenters coincide with the location of the injection wells. In Youngstown, Ohio, earthquakes of anthropogenic origin have reached magnitudes of up to 5.7.
The injection of wastewater from oil and gas production operations, including fracking, into brine disposal wells, can cause more intense earthquakes, of which up to magnitude 3.3 have been recorded. According to seismologists at Columbia University, several earthquakes that occurred in 2011, including one of magnitude 4.0 that was felt in Youngstown, Ohio, could be related to the discharge of residual waters from fracking. The United States Geological Survey has stated that there is no guarantee that earthquakes of greater magnitude will not occur due to this technique.
On the other hand, the frequency of these earthquakes has been increasing in the United States. In 2009 there were 50 earthquakes greater than magnitude 3.0 in the area that covers from Alabama to Montana; in the same area, in 2010, 87 tremors were recorded and, in 2011, there were 134; In total, there was a six-fold increase in the frequency of recorded earthquakes during the 20th century.
When asked, is it valid to oppose all-natural gas? The answer and the underlying question is why do we want more gas? Especially one whose extraction causes such serious damage to the environment and health.
No matter how much gas could be obtained in the world with fracking, which is yet to be evaluated, renewable energies are the energy resources that we have in abundance and those that we should develop and use since they are technologies that already exist, and whose negative impacts they are much smaller and business and technology sectors are willing to take advantage of them.
Since several studies show that it is possible to achieve an energy system based entirely on renewable energy, it is absurd to undertake a new search for more fossil fuels with serious potential adverse impacts on the planet, in addition to the risk of diverting resources and energy. efforts that should be concentrated on the development and application of renewable energies and energy efficiency.
The promoters of fracking promise important advantages even for the environment, but behind these optimistic declarations, there is a purely economic interest.
Finally, even if fracking were successful and its risks did not outweigh its benefits, the only thing that would be achieved is to prolong humanity’s dependence on fossil fuels, which are limited and whose use is incompatible with climate stability.
Recognition of the enormous potential of this important resource can only be achieved by resolving current controversies through adequate research, sustainable policies, and effective regulation. Fact-based regulations and policies based on sound science are crucial if shale gas is to be made available while ensuring the protection of human health and the environment.