Water contamination could also occur if a well is improperly installed, if chemicals are spilled from trucks or tanks, or if flowback is not effectively contained. Flowback is when water used in the hydraulic fracturing process flows out of the well. The extent of water contamination from these sources is currently unknown. Indirect evidence shows water contamination related to fracking influences health. But direct evidence is needed. Drilling sites can potentially affect local air quality in several ways.
First, any process involving combustion can release toxic chemicals into the air. For example, the burning off, or flaring, of excess natural gas; the operation of heavy equipment at the well site; and the use of diesel trucks to transport materials to and from a site may all contribute to air pollution.
In addition, the chemicals and sand used in the hydraulic fracturing process, as well as other chemicals that surface with the natural gas, may potentially become airborne and affect air quality. The long-term effects of fracking on general populations are also unclear, but are likely to include increased cancer rates. Many of the chemicals that have been detected in the drinking wells and air surrounding fracking wells are known carcinogens, but because cancer can take years to develop, their effect on cancer rates in these regions is still unknown.
In addition, not all of the chemicals that are commonly used have been tested for carcinogenic effects. Even if all of these untested chemicals were harmless in isolation, multiple chemicals can interact in unknown ways in the body, sometimes amplifying the carcinogenic effect. This systematic flaw in scientific toxicity testing causes problems for determining the exact effects of drinking water that is polluted with multiple fracking fluid chemicals.
Chemical interaction is only one field of study where there is an acute need for more research into the health effects of fracking.
The potential reproductive health impacts described earlier are not proven because most studies have been relatively small-scale.
These studies are suggestive of health hazards, but are not conclusive. In order to protect the health of residents in fracking areas, however, it is necessary to know exactly what risks they face.
In addition to physical health, the development of the fracking industry can impact the mental and social health of communities.
Most of the new extraction areas are in very rural parts of Pennsylvania, the Dakotas and Texas. The influx of workers creates shale gas boomtowns and increases industrial pollution within the area. Many residents express concerns about sleep disruption from increased traffic, and increasing levels of drug use and sexual assault. Although fracked natural gas is often touted as a cleaner and more environmentally friendly alternative to coal and oil because it produces less carbon dioxide when burned, most measurements do not account for methane leakages that occur and the number of truck trips that are required for fracking wells.
Fracking presents a quandary for lawmakers. Should an industry with unclear, but potentially serious, detrimental effects on health be allowed to proceed? Should a ban only be implemented once there is conclusive evidence of harm?
Within the United States, individual states have answered these questions differently. For example: although New York and Pennsylvania both lie on top of the Marcellus shale formation, their governments have regulated fracking in completely opposite ways.
In , New York implemented a temporary moratorium on fracking while the health and environmental departments investigated its impacts. After seven years of study, the decision was made to extend the ban. In contrast, neighboring Pennsylvania has aggressively pursued fracking.
There are currently 7, fracking wells in the state and the number is projected to continue to increase. Fracking employs 33, people in the state and financially benefits those who own mineral rights and lease their land to fracking companies. This means, however, that they are gambling with health; if fracking has as severe a health effect as some studies suggest, it may dramatically increase rates of cancer, asthma and reproductive disorders before being proven to cause conclusive harm.
Once an unconventional oil or natural gas well is producing, there is no detectable sound from the operation. Hydraulic fracturing occurs far below the groundwater aquifer. Groundwater is protected by thousands of feet of impermeable rock and an engineered well casing design consisting of several layers of steel casing and cement to provide isolation.
The multiple layers of impermeable rock between the water supply and the gas-bearing rock ensure the fracks do not extend into the groundwater aquifer. Viable sources of unconventional oil and natural gas can sometimes be found in small, isolated zones within a few yards of each other.
During the drilling stage, a vertical wellbore is typically drilled one to one and a half miles below the surface. Multiple horizontal deviations can then be drilled to reach the different target reservoirs. Horizontal drilling has led to the development of multi-well pad technology, which allows for one drill site to include a number of producing wells that can access reservoirs up to 8, feet away from the vertical well.
Instead of having single well pads spread throughout the community, multi-well pads can significantly limit the surface impact. Safety of people, communities and the environment is the top priority for all responsible companies and authorities working to develop unconventional gas resources.
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