Sources and impacts of groundwater pollution in America

Groundwater Pollution Issues

How does America's groundwater become polluted and what are the sources of pollution that goes into the groundwater? How important is unpolluted groundwater to the sustainability of communities? Also, what are the solutions for this pollution of the groundwater? These issues and others will be reviewed in this paper.

Groundwater Facts

According to William M. Alley, writing in the peer-reviewed journal Environment, groundwater exists "…almost everywhere beneath the land surface" and it plays a "crucial role in sustaining streamflow between precipitation events" and in particular during "protracted dry periods" (Alley, 2006, p. 16). Alley explains that about 85 billion gallons of groundwater are "withdrawn daily," and upwards of ninety percent of that water is used for "…irrigation, public supply (deliveries to homes businesses, industry) and self-supplied industrial use" (Alley, 16). Of those 85 billion gallons withdrawn from groundwater sources daily, nearly two-thirds is used for irrigation, Alley explains. Also, groundwater provides about half of the drinking water needed by U.S. communities, and moreover, there is a problem with groundwater in that information on its use is "…spotty and often inaccurate within the United States" (Alley, 17). Laws that regulate the use of groundwater "…vary significantly from state to state and from one water-use category to another…" (Alley, 17).

Sources of Groundwater Pollution

What is known about groundwater however is that it can become contaminated with pollutants, including the use of pesticides. The United States Geological Survey reports that the United States is the "…largest producer of food products in the world," and one of the main reasons that the U.S. can claim that title is because of the use of chemicals like pesticides to "…control the insects, weeds, and other organisms that attack food crops" (USGS). But there is a cost that is associated with the heavy use of pesticides, and in fact "..,.pesticide contamination of groundwater" has national implications because, as mentioned earlier in this paper, about half of the nation uses groundwater for drinking purposes (USGS, p. 1). In the agricultural areas where most crops are grown -- and hence, where pesticides are most often used -- about "…95% of that population relies upon ground water for drinking water," the USGS explains.

Thirty or so years ago it was believed that the soil acted as "…a protective filter that stopped pesticides from reaching groundwater," but recent studies prove that is not the case. In fact pesticides do reach groundwater aquifers from the use of pesticides in crops above, they do reach aquifers when contaminate surface water seeps down through the soil, where there are "accidental spills and leaks" or "improper disposal" -- and even through "injection waste materials into wells," the USGS continues. The polluting chemicals from pesticides may not reach groundwater sources for years (there is an ongoing study of this problem), but because "many hundreds of these compounds" are in use, the resulting danger to drinking water is of great concern to communities.

Hydraulic Fracturing or Fracking

Pesticides are not the only source of pollution for groundwater resources. The USGS explains that there is "…an increasing public concern about the effects of energy production on surface-water and groundwater quality" (USGS, 2012). The concerns are raised because the system of "hydraulic fracturing" is being used more frequently by energy companies as they search for oil and gas. Part of the system of hydraulic fracturing calls for horizontal drilling in "los permeability formations," the USGS continues. In the first place, oil drilling companies can contribute pollution to groundwater from the surface as well as below ground. At the drill site (or production facility) there can be "…leaks from pits or tanks, chemical spills, and discharge of wastewater," all of which can contaminate groundwater quality (USGS, p. 1). And leaks due to hydraulic fracturing, from "failed casing seals, pipeline breaks, abandoned wells, deep-well disposal of flowback or produced wastewater," all can pollute groundwater resources (USGS).

A Discussion of a Contemporary Issue -- Hydraulic Fracking / Fracturing

In order to reach oil and gas reserves that exist in subsurface fracture systems the energy companies are utilizing a strategy called fracking or hydraulic fracturing. Chemicals and other fluids are pumped into a geologic formation "…at high pressure," and when the pressure "exceeds the rock strength, the fluids open or enlarge fractures that can extend several hundred feet away from the well," according to the Environmental Protection Agency (EPA, 2012). A "propping agent is pumped into the fractures" so they won't close when the pressure is released, and the internal pressure causes the fluids pumped into the fractures to "rise to the surface where it may be stored in tanks or pits prior to disposal or recycling." These fluids are called flowback, and it is how companies get the oil out of the earth from a place where previously a well had been dug and most of the easily extracted oil was removed.

Is fracking a safe technology? The Natural Resources Defense Council (NRDC) supports federal regulation of hydraulic fracturing under the Safe Drinking Water Act based on data that the NRDC has gathered showing negative impacts to the environment. For example, in June, 2010, when hydraulic fracturing began on a gas well near Tracy Dahl's ranch in Las Animas County, Colorado, the ranch owner discovered "…approximately 500 gallons of grayish brown murky water where water had previously run clear for years" (Mall, 2011). The Dahl family provided documentation as to the safe and clean drinking water from their well going back many years, in an attempt to prove that fracking contaminated their water supply. But the Colorado Oil and Gas Conservation Commission told the family that their well (albeit it seemed certain to have been contaminated) "could not be tested for chemicals in the hydraulic fracturing fluid because there is insufficient information about the chemicals used" in the fracking project (Mall, p. 1).

Mall reports dozens of incidents in which water has been polluted by fracking. In Pennsylvania in 2009, the Zimmerman family in Washington County reported that their drinking water had been contaminated right after a fracking project (a project that was seeking natural gas through old wells owned by Atlas Energy). Testing proved that: a) the presence of mercury and selenium were above EPA limits; b) arsenic was 2,600 times "acceptable levels"; c) benzene was 44 times above limits; and d) naphthalene was five times above the federal limit (Mall, p. 2). In Texas, three families share an aquifer in Grandview, and following a fracking incident in a nearby gas well they reported "…strong odors in their water, changes in water pressure, skin irritation, and dead livestock" (Mall, p. 2).

When the families had their aquifer tested, among other contaminants the results showed high levels of toluene. These are but three of the dozens of verified incidents of pollution of drinking water and groundwater contamination from fracking.

In addition to the problems related to hydraulic fracking (or fracturing, as some refer to it) and abandoned wells, the USGS released a report in 2010 that "Elevated concentrations of nitrogen and phosphorus…have remained the same or increased in many streams and aquifers" in the U.S. since the 1990s (Dubrovsky, 20110). The reason for concern is that these concentrations of nutrients can have a negative impact on aquatic ecosystems and human health because they can result in "dead zones" once these waters reach estuaries. As to human health, many shallow aquifers around the U.S. -- that are the sole source of drinking water for many people -- contain nitrate levels at levels that exceed EPA standards, Dubrovsky writes on page 2. Concentrations of nitrogen in aquifers are the highest in agricultural areas in the Northeast, the Midwest, and Northwest, areas where the use of fertilizer and manure are the greatest, Dubrovsky continues.

The Sierra Club's response to the EPA's flimsy oversight vis-a-vis hydraulic fracturing (submitted to the EPA Science Advisory Board Meeting in 2010) indicates that the track record "thus far is poor," in respect to fracturing for natural gas found in shale deposits. In fact the study that the EPA conducted in 2004 -- which showed that fracturing strategies posed "little or no threat" were "terribly flawed," according to Craig Holt Segall, an attorney with the Sierra Club. Since the day-to-day practices of the oil and gas industry as they use fracking to search for more energy sources are "messy" and allow the companies to "skirt the rules" -- something should be done to regulate the fracking that is ongoing, Segall explained.

In conclusion, from the materials presented in this paper, it is clear that there are many threats to groundwater supplies in the United States. There are too many examples of pollution that flows into groundwater aquifers from fertilizers, pesticides and other chemicals used to control bugs and weeds. There are many examples of pollution resulting from abandoned gas and oil wells, and the evidence shows fracking to search for oil and gas can have very negative impacts on drinking water supplies as well. The citizens of the U.S. expect their government to have oversight over matters that pertain to safe, health supplies of water, but at this point there are questions as to whether oversight is adequate. It would seem that federal regulations should be instituted to protect people and still allow for the save exploitation of oil and gas resources.