Researchers at the Tyndall Centre at Manchester University, England, investigated the impacts of shale gas on the environment and climate change. The exploitation of shale gas, or shale, is launched in the U.S. and will begin soon in Britain.
is the 8th part of a loose translation of the preliminary report Tyndall Centre for Climate Change Research. The original is here:
http://www.tyndall.ac.uk/shalegasreport
with a link to download the report in pdf format of 87 pages.
The report's title is: 
4. Impacts on human health and the environment 4.1 Introduction 4.1.1 Context processes involved in the production of shale gas have been described detail in Section 2.2 of this report and the resource levels for the development of a drilling site were summarized in Tables 2.6 and 2.7.
4.1.2 The importance of cumulative impacts
Probably no surprises, processes and operations required to extract the shale gas wells are not without impacts on human health and the environment. For example, as we will detail below, human health and environmental risks due to hydraulic fracturing particuliler have emerged in a major way in the United States. Here, there were a number of incidents and reports of contamination holdings of shale gas, and March 3, 2010, U.S. EPA announced a comprehensive research study to investigate the potential negative impacts of hydraulic fracturing on water quality and public health .
By cons, while the new risks associated with hydraulic fracturing of wells could generate debate, such risks and impacts are not the only désanvantages exploitation of shale gas, especially if done in countries relatively populous as Britain. Here, although it is tempting to focus on the risks associated with individual processes in the production of shale gas and incidents reported, it is also important to consider the impacts of shale gas in their entirety.
These impacts are best known heavy traffic, landscape, noise and water consumption are all important mainly inhabited environment where competition for resources is greater, as in UK Cumulative impacts could be a source of worry, too, when one takes into account the intensity of the operations needed to produce enough volume to make it pay.
To spread the cumulative impacts in context, Table 2.8 presents estimates of resource requirements needed to achieve gas production 9bcm a rate per annum (equivalent to 10% of gas consumption in UK in 2008) for 20 years. To support this level of production for 20 years in UK would require approximately 2.500 to 3.000 horizontal wells spread over a land area of 140 to 400 km2, and between 27 and 113 million tons of water.
4.1.3 The main risks and impacts
The main risks and impacts of shale gas and mining process and its development are as follows:
- contamination of groundwater by fluids fracturing, contaminants mobilized following: a leak forms, the well or groundwater migration;
- pollution of soil and surface water (and possibly the groundwater surface) due to accidental spills of the additives of fracturing or spills or leaks or overflows from storage locations of wastewater, settling ponds contain waste drilling, drilling mud or sewage flowback;
- water consumption
- treatment of wastewater
- impacts on soil and landscape
- the impacts during construction: noise, light pollution during drilling and completion of wells, gas flares or vents, travel vehicles.
4.2 The impacts of pollution
4.2.1 Introduction The pollution impacts of the exploitation of shale gas associated with the process of hydraulic fracturing, chemicals used in fracturing fluids, products processing and underground contaminants that are mobilized during the process. To date, there is little information available on additives fracturing and risks associated with hydraulic fracturing. Federal law exempts the U.S. injection of fluids into the ground to the hydraulic fracturing of laws and a large number of receipts were recorded sercrets as commercial under the Public Officers Law.
Given the recent growth of the industry shale gas and mounting concerns the U.S. public, media and Congress, U.S. EPA announced in March 2010 it would conduct a comprehensive research study to investigate the potential negative impacts of hydraulic fracturing on water quality and public health. The U.S. EPA notes the concerns that hydraulic fracturing could impact groundwater quality and surface water so as to endanger public health and the environment, and spends $ 1.9 million for the study in fiscal year 2010 and requesting funding for 2011 in the President's budget proposals.
The U.S. EPA is still in the early stages of its research program on hydraulic fracturing and preliminary results will be available towards the end of 2012. While this and other evaluations are running, some legislators are forging ahead towards a moratorium on hydraulic fracturing. In upstate New York, for example, 3 August 2010, the Senate passed a Bill to suspend all hydraulic fracturing for purposes of extraction of natural gas or oil until May 15, 2011 (and for stop granting permits for such drilling). On 11 December 2010 the Governor of the State of New York has had a veto and has issued an Executive Order, directing the Depaertment of Environmental Conservation (DEC) to pass comprehensive review and analysis of hydraulic fracturing in the Marcellus Shale intensive. It requires intensive horizontal hydraulic fracturing is not allowed until July 1, 2011.
Questions hydraulic fracturing and the risk to human health and the environment are under surveillance in the United States. Meanwhile, for cons, there is very little information and data to make an assessment on environmental hazards and public health. That said, this short study seeks to be gathered the information that is available and provide an overview of key issues, concerns and challenges of a particularly British perspective.
4.2.2 The fracturing fluids and wastewater flowback
As mentioned in Section 2, a fracturing operation in several stages involves the injection of fracturing fluids at very high pressures in the hole drilled to cause fractures in the rock formation targeted. The fracturing of a single well requires a large volume of water with chemical additives ranging up to 2% of the volume, thus 180 to 580 cubic meters of chemical additives (or 180 to 580 tons according to the relative density). After fracturing, some fluids back to the surface (flowback).
The chemical composition of the fracturing fluids
The composition of the fracturing fluids varies from one product to another, and the recipe varies depending on the fluid and the characteristics of the target formation and objectives of operations. Fracturing fluids used in modern hydraulic fracturing are typically composed of about 98% water and sand (proppant) with chemical additives which accounted for 2%.
Taking into account the fact that federal law exempts the U.S. underground injection of fluids for hydraulic fracturing of existing laws, there is no Informationis the identity and concentration of substances revenues in hydraulic fracturing. The disclosure of the chemicals used in hydraulic fracturing may be required on a case by case basis, and as in the upstate New York, for example, the Department of Environmental Conservation requires that operators divulquent the chemical as part of the procedure Permit application. For cons, the documents of the New York State (2009) show that full disclosure of chemical elements revenue is not possible due to exemptions from trade secrets to public disclosure. In this way, as mentioned in the comments of the City of New York in the document New York State (2009), this means that shareholders as the city and local health departments have no knowledge of chemicals that are released into environment near the sources of drinking water.
In terms of disclosure to the public, operators are required to provide MSDSs for chemicals stored over 10,000 pounds (4.5 tons) according to the U.S. Emergency Planning and Community Right to Know Act 1986 (EPCRA). However, it does not provide any information likely to chemicals or give the concentrations of substances. Due to the lack of detailed information on the chemical composition, this evaluation must rely on information extracted from data sheets supplied by the operators to legislators. For this, the document New York State (2009) provides us with a list of 260 chemical components and their CAS numbers have been taken in the information of chemical products of 197 and rebates MSDSs to NYSDEC.
A revision of this list was made by cutting the numbers of cases in the list of NYS with the following lists the European Chemical Substances Information System (ESIS) (see Appendix 1 for full list):
- toxic classification: For purposes of classification and labeling
- the list of priority substances Showing 1-4: Since 1994, the European Commission has published four lists of substances that require immediate attention because of their potential effects on humans and the environment. There are 141 substances on the lists;
- the first list of 33 priority substances: Member States must gradually reduce the pollution of priority substances;
- the list of PBT substances that have undergone assessments PBT according to their strategy Interim Strategy for REACH and the ESR program. For substances that are persistent, bioaccumulative and toxic (PBT) or very persistent and very bioaccumulative (vPvB), an acceptable concentration in the environment can not be determined with sufficient accuracy. This analysis suggests that 58 of 260 substances have one or more properties that could be disturbing and:
- 15 substances are in one of four priority lists;
- 6 are in the list 1 (acrylamide, benzene, ethyl benzene, isopropylbenzene (cumene), naphthalene, tetrasodium ethylenediaminetetraacetate);
-1 is under investigation at this time as a PBT (naphthalene bis (1-methylethyl));
- 2 are in the first list of 33 priority substances (naphthalene and benzene);
- 17 are classified as toxic to aquatic organisms a how serious or chronic
- 38 are classified as toxins serious damage to human health;
- 8 are classified as known carcinogens
- 6 are classified as suspected carcinogens;
- 7 were classified as mutagenic
- 5 are classified as having effects on the reproductive systems.
is clear that the presence a number of substances in fracturing fluids may be cause for concern, especially because of the use that we will make and the amounts used. The level of risk associated with use of these substances will depend on the quantity and concentration of substances, where they lead and tracking the exposure of humans and the environment. The latter will be discussed in subsequent sections of the report.
All first fracturing operations (that is, without subsequent re-fracturing) on a site of 6 wells (six single well pad) requires a total of 1.000 to 3.500 cubic meters of chemicals. In Assuming that there are 1.25 to 3.5 sites per square kilometer of 3.780 to 12.180 cubic meters (or 3, 780 to 12.18 tonnes depending on the density) of fracturing chemicals may be necessary for the operation shale gas of 1 square kilometer. According to data from the table 2.8, 140 to 400 square kilometers operating shale gas containing 2.500 to 3.000 horizontal wells would be needed to produce 9bcm/année (or 10% of consumption of GB in 2008). This represents the high-pressure injection of 0.5 to 2.2 million cubic meters (or tonnes, according to the relative density) of chemical fracturing.
Wastewater return (flowback)
15% to 80% of injected fluids back to the surface flowback (and thus 20% to 85% remains below ground). Flowback fluids include course fracturing fluids injected into the well, but also contain:
- chemical processing that could have taken shape due to reactions between additives fracturing;
- substances mobilized to within the shale formation during hydraulic fracturing;
- naturally occurring radioactive materials already in the shale formation (NORM).
The nature and concentrations of substances will certainly vary from shale formation to another, and in the UK, it is difficult to predict the composition of the waters of flowback. For example, New York State 2009 provides us with very little data of composition of specimens of fluid flowback. This analysis was based on limited data from Pennsylvania and West Virginia. Analytical methods and detection levels used were not standardized for all parameters and one must take into account the composition of the flowback of a single well can also change a few days after fracturing.
By comparing the data visually Substance fracturing fluids with data wastewater flowback, one might infer that there is engagement and presence of high concentrations of:
- heavy metals of various types;
- radioactivity and standards;
- total dissolved solids;
- perhaps hydrocarbons including benzene (not sure if they are mobilized or oil additives to fracturing).
In all, the profile of toxic fluid flowback is likely to be a source of much concern that the fracturing fluids themselves, and will probably be perceived as hazardous waste in UK The amount of waste generated and the requirements for storage and industrial wastewater treatment are also enormous. Table 4.1 is based on recovery rate of 15% to 80% recovery of fracturing fluids into flowback taking into account the different volumes of fracturing fluids used. This suggests that to understand the operation of the shale gas to produce 9bcm/année, 5 to 89 million cubic meters of hazardous waste must be recovered and would require treatment and storage. It is also important to know that drinking water and varying rates of recovery would say that if 15% to 80% of fluids are recovered, then between 205 and 80% of the fluids are not recovered and thus remain underground.
The following free translation of the Tyndall report will address the impacts on the contamination of groundwater contamination by land, water consumption, visual pollution and noise, and Tyndall report's findings in a blog entry soon.
Photo: www.marcellus-shale.us
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