ground water contamination

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1 GROUNDWATER CONTAMINATION Abdulrahman Ahmed Salah - 43780375 Ground Water Engineering - 803662 Civil Engineering Department Umm Al-Qura University Abstract The water contamination is a widely common problem relating to the field of environmental and water resource engineering. It requires very sophisticated techniques to prevent the occurrence of contamination in ground or shallow water resources by all available prevention methods. This research discusses the different sources of ground water contamination and the effects of contaminated water on the health and environment. In addition to some details about the protection methods to keep water useable and finally recommendations and conclusion. This research is a part of the fulfillments of the Ground Water Engineering course. 1. Introduction Water contamination may occur for any available water resource and may make it unusable water due to the change in the water properties. Water contamination is a main problem of the globe, which needs ongoing assessment and reconsideration of water resource policies around the world neither by the governments or any relating authorities. Water contamination is one of deaths and diseases causes, and that it is the reason for the deaths of more than 14,000 people daily. [1] Approximately, statistics show that 90% of the water in the cities of China is contaminated. [ 2] In 2007, almost 500 million of Chinese had no access to safe drinking water. [ 3] Groundwater is the term used to describe the water that is existed in soil pores beneath the surface and in permeable geological formations. Sources of groundwater include seepage from the land surface, such as rainwater, snowmelt and water also that permeates down from the bottom of some lakes and rivers. [ 4] Fossil groundwater is water that has been trapped in rock formations over geological time scales. Groundwater is a very important source of freshwater, making up 97% of the accessible freshwater reserves in the world. [5] Water is considered as contaminated water when it is impaired by anthropogenic contaminants and either does not support domestic uses, such as drinking water, or undergoes a marked shift in its ability to support its constituent biotic communities, such as fish. Natural phenomena such as volcanoes, algae blooms, storms, and earthquakes commonly change the water quality and the biological status of water. [ 6]

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Page 1: Ground water contamination

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GROUNDWATER CONTAMINATION

Abdulrahman Ahmed Salah - 43780375 Ground Water Engineering - 803662

Civil Engineering Department Umm Al-Qura University

Abstract

The water contamination is a widely common problem relating to the field of environmental and water resource engineering. It requires very sophisticated techniques to prevent the occurrence of contamination in ground or shallow water resources by all available prevention methods. This research discusses the different sources of ground water contamination and the effects of contaminated water on the health and environment. In addition to some details about the protection methods to keep water useable and finally recommendations and conclusion. This research is a part of the fulfillments of the Ground Water Engineering course.

1. Introduction

Water contamination may occur for any available water resource and may make it unusable water due to the change in the water properties. Water contamination is a main problem of the globe, which needs ongoing assessment and reconsideration of water resource policies around the world neither by the governments or any relating authorities. Water contamination is one of deaths and diseases causes, and that it is the reason for the deaths of more than 14,000 people daily. [1] Approximately, statistics show that 90% of the water in the cities of China is contaminated. [2] In 2007, almost 500 million of Chinese had no access to safe drinking water. [3]

Groundwater is the term used to describe the water that is existed in soil pores beneath

the surface and in permeable geological formations. Sources of groundwater include seepage from the land surface, such as rainwater, snowmelt and water also that permeates down from the bottom of some lakes and rivers. [4] Fossil groundwater is water that has been trapped in rock formations over geological time scales. Groundwater is a very important source of freshwater, making up 97% of the accessible freshwater reserves in the world. [5]

Water is considered as contaminated water when it is impaired by anthropogenic

contaminants and either does not support domestic uses, such as drinking water, or undergoes a marked shift in its ability to support its constituent biotic communities, such as fish. Natural phenomena such as volcanoes, algae blooms, storms, and earthquakes commonly change the water quality and the biological status of water. [6]

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2. Background

Human activities usually resulted in Ground water contamination. Ground water is easily become contaminated where high population density and human uses of the land is intensive. Nearly, any activity whereby chemicals or wastes may be disposed to the environment, either intentionally or by accident, has the potential to contaminate ground water. When ground water becomes contaminated, it is difficult and expensive to purify.

Over 50% of the United States population depends on groundwater for drinking water. Groundwater is also one of our most important sources of water for irrigation. Unfortunately, groundwater is susceptible to pollutants. [7]

Water contamination may be caused by chemical, physical, radioactive or pathogenic microbial substances. Contaminated used water currently produces large scale diseases and deaths, accounting for approximately 50 million deaths per year worldwide, most of these deaths occurring in Africa and Asia. Widespread consequences of water contamination upon ecosystems include species mortality, biodiversity reduction and loss of ecosystem services. Some consider that water contamination may occur from natural causes such as sedimentation from severe rainfall events; though, natural causes, including volcanic eruptions and algae blooms from natural causes constitute a minute amount of the instances of world water pollution. The most problematic of water contaminants are microbes that induce disease, since their sources may be interpreted as natural, but a majority result from human activities. [9]

Materials from the land surface can move through the soil and end up in the groundwater. For example, pesticides and fertilizers can find their way into groundwater supplies over time. Road salt, toxic substances from mining sites, and used motor oil also may seep into groundwater. Furthermore, it is likely for untreated waste from septic tanks and toxic chemicals from underground storage tanks and leaky landfills to contaminate groundwater. [9]

Contaminated drinking water always have serious health effects and in some cases, lead to death. Diseases such as hepatitis and dysentery may be caused by contamination from septic tank waste. Poisoning may be resulted from toxins that have leached into water good supplies.

Ground water and surface water are interconnected and can be fully understood and intelligently managed only when the surface waters and ground waters interrelation is acknowledged. If there is a water supply well near a source of contamination, that well runs the risk of becoming contaminated. If there is a nearby river or stream, that water body may also become contaminated by the ground water [8]

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3. Groundwater Contamination Sources

Water contaminant sources can be categorized into two super categories: [9]

Point sources: discharge from a factory or sewage outfall, and include many of the common inorganic chemical water contaminants; and

Non-point sources that include agricultural runoff, urban storm water runoff and other area wide sources.

Fig. 1, below illustrates the most common sources of ground water contamination and the interrelation between surface and ground water. These types of contaminants will be discussed in details in the following pages of this research.

Fig. 1 Potential Sources of Contamination in Groundwater [UK Groundwater Forum]

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Ground water contaminates from natural sources or numerous types of human activities. Residential, municipal, commercial, industrial, and agricultural activities can all affect ground water quality. Contaminants may spread into the ground water from activities on the land surface, such as releases or spills from stored industrial wastes; from sources below the land surface but above the water table, such as septic systems or leaking underground petroleum storage systems; from structures beneath the water table, such as wells; or from contaminated recharge water. Another classification of ground water contaminants is mentioned below:

A. Natural Sources: Iron, manganese, arsenic, chlorides, fluorides, sulfates, or radionuclides, can become dissolved in ground water naturally from rocks or soils. Decaying organic matter, can move in ground water as particles. Ground water that contains unacceptable concentrations of these substances is not used for drinking water or other domestic water uses unless it is treated to remove these contaminants. Some substances may cause health threats if consumed in excessive quantities; others may produce an undesirable odor, taste, or color of water. [8]

B. Septic Systems Septic tanks, cesspools, and privies are most common types of ground water contaminants. Improperly sited, designed, constructed, or maintained septic systems can contaminate ground water with bacteria, viruses, nitrates, detergents, oils, and chemicals. Along with these contaminants are the commercially available septic system cleaners containing synthetic organic chemicals. Fig. 2, shows the septic system causing contamination to the beneath ground water aquifer.

Fig. 2 Contamination by Septic System [myactivator1000.com]

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C. Sewage and waste water Sewage water carries harmful bacteria, organic matter, inorganic salts, heavy metals, viruses, nitrogen and chemicals that can cause serious health diseases. Pathogens are known as a common water contaminant; The sewers of cities house several pathogens and thereby diseases. Sewer pipes carrying wastes sometimes leak fluids into the surrounding soil and ground water. Pipelines carrying industrial chemicals and oil brine have also been known to leak, especially when the materials transported through corrosive pipes. Fig. 3, below display a leakage in a sewage pipe into water that seepage into the soil to the ground water causing contamination.

Fig. 3 Sewage Pipes Leakage as Contaminant [pugetsoundblogs.com]

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D. Landfills Thousands of tons of disposed solid waste of industrial landfills represent one of the main contamination resources of groundwater. Landfills is defined as the places where the garbage is taken to be disposed. Landfills must have a protecting bottom layer to avoid contamination of water. Although, in some cases the protective layer is cracked or damaged, so contaminants from the landfill can pass through soil to the groundwater.

Fig. 4 Unregulated Landfill [www.emaze.com/@ALZZLFRO/Lithosphere]

Moreover, disposals from many household wastes are not sufficiently regulated, so, the chemicals can leak into the ground water by means of precipitation and surface runoff. Closed landfills can continue to pose a ground water contamination threat if they are not covered with an impermeable material before closure to prevent the leakage of contaminants by precipitation.

Fig. 5 Landfill Contaminants Action on Groundwater [www.atsdr.cdc.gov]

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E. Surface Impoundments Surface impoundments include the natural topographic depressions, man-made excavations and diked areas that primarily are made of earthen materials and which hold liquid wastes. These uncovered areas are commonly used to volatilize and/or settle materials. As many as 180,000 surface impoundments exist in the United States. Like landfills, new surface impoundment facilities are required to have liners, but even these liners sometimes leak. [8]

F. Chemical fertilizers and pesticides Chemical fertilizers and pesticides are used to prevent damaging the crops by insects and bacteria. They are help plants to grow. Though, when these chemicals are mixed up with water, there will be harmful product for plants and animals. Similarly, when it rains, the chemicals mix up with rainfall and flow down into rivers and canals which pose serious damages for aquatic animals.

G. Injection Wells An injection well is used to place fluid underground into porous geologic formations. These underground formations may range from deep sandstone or limestone, to a shallow soil layer. Injected fluids may include water, wastewater, brine or water mixed with chemicals. [8] Injection wells are usually used for collecting storm water runoff, collecting spilled liquids, dispose of wastewater, and dispose of industrial, commercial, and utility wastes. The injection wells used in region are typically shallow and include sumps and dry wells used to handle storm water.

H. Urban development More cities and towns are developed to encounter the population growth, they have resulted in increased usage of fertilizers to increase the food production, soil erosion due to deforestation, increase in construction activities, inadequate sewer collection and treatment, landfills as more garbage is produced, increase in chemicals from industries and produce more waste materials contaminating groundwater.

I. leakage of Underground storage Chemical and petroleum products through transported by underground pipes is well known resource of contaminants of groundwater. Accidentals leakage may happen anytime and cause damages to the environment and result in soil erosion.

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Resources of groundwater contamination are various and cannot be limited to specific resources, however, we can say that any material from any resource can change the water properties is a contaminant. Table 1, below show the groups of groundwater contaminants by their type and origin.

Table 1 Ground Water Contaminant Categories and Examples

Category Common Contaminants

Physical sediment or organic material suspended in the water of

lakes, rivers and streams from soil erosion

Chemical

Nitrogen Bleach Salts Pesticides Metals Toxins produced by bacteria, and human or animal drugs.

Biological

Bacteria Viruses Protozoan Parasites

Radiological

Cesium

Plutonium

Uranium

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4. Groundwater Contamination Impacts

The effects of groundwater contamination are widespread. Human infectious disease are the most serious effects of water contamination especially in rural areas that are still developing and where sanitation is hardly regulated. This might cause hundreds of thousands of diseases in the contaminated groundwater areas. An average 7 million people are sickened in the US from drinking polluted water yearly. [10] the problems are not only of drinking water, but also domestic uses and swimming water.

Not only are we effected by water contamination but so are animals are affected and damaged by groundwater contamination. Nitrogen, phosphorus, and other nutrients come from groundwater contamination can make the area as a coastal zone and that means it can stimulate harmful overgrowths of algae, can have direct toxic effects and result in low-oxygen conditions. Some algae are toxic and zooplankton eat it causing the contamination to go through the food chain and eventually harming use with disease or death.

The consequences of contaminated ground water are often serious. In some instances, ground water contamination is so severe that the water supply must be abandoned as a source of drinking water. In other cases, the ground water can be cleaned up and used again, if the contamination is not too severe and if the municipality is willing to spend a good deal of money. Follow-up water quality monitoring is often required for many years.

Health effects from groundwater contamination depend on the specific contaminants in the groundwater. Contamination from groundwater often causes diarrhea and stomach irritation, which can lead to more severe health effects. Accumulation of heavy metals and some organic contaminants can lead to cancer, reproductive abnormalities and other more severe health effects. [11] Fig. 6, shows effects of contamination on fish.

Fig. 6 Groundwater Contamination Effects on Animals [blogs.fanbox.com/]

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Effects of groundwater contamination could be classified into three main groups, so they could be separately understood. Table 2, below shows the three groups of groundwater contamination effects.

Table 2 Effects of Groundwater Contamination

Group Description Examples of effects

Health Effects

Health effects are the most common problems associated with groundwater contamination.

Hepatitis Septic systems may infect groundwater with hepatitis due to human waste present in the water supply. Hepatitis is a very serious problem that causes irreversible damage to the liver.

Dysentery Dysentery induced by contaminated drinking water by waste materials of human or animal in nature.

Poisoning Poisons from both nature and from human use of pesticides and solvents can leach into the water well if it is not placed correctly. Poisons can make humans and animals very sick and may cause death. Bone tissue & tooth discoloration Excessive consumption of fluoride can damage bone tissue. Also, too much fluoride can cause tooth discoloration in young children. [8]

Cholera or giardiasis Mainly caused by contaminated water

Environmental Effects

The environment can be seriously damaged when groundwater is contaminated.

Nutrient pollution [12] Groundwater contamination is the cause of nutrients certain types, it is necessary in small amounts to become far too abundant to sustain normal life in a given ecosystem. Fish might start dying off quickly because they are no longer able to process the water in their water supplies Animals could become sick from excessive certain types of nutrients in the water they drink. Plants may not be able to absorb water easily, and the entire ecosystem of plants will suffer.

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Toxic water in ecosystems [12] contamination of the surface water is increased when the groundwater that supplies lakes, rivers, streams, ponds, and swamps is contaminated. The contamination of surface water cause destruction of the wetlands, which depend on heavily on groundwater to recharge their lakes and ponds. Persistent organochlorine insecticides [13] Lake sediments contains persistent organochlorine insecticides can bioaccumulate, harming the fish and birds that eat them. Pyrethroid insecticides, though derived from chrysanthemums, are extremely toxic to aquatic organisms. Soil Contamination When the ground water become contaminated, the soil over the contaminated aquifers will not be useable.

Economic Effects

The economy and industries might be easily suffering and negatively affected when groundwater becomes contaminated.

Agricultural activities Once the groundwater is contaminated, this will definitely damage the agricultural sector and cause the death of plants and farms producing various of needed corps. As well as the vegetation needed for other purposes such as soil stabilization in coastal areas.

Depreciating value of land contaminated groundwater in a given area, that makes the area less capable of sustaining human, animal, and plant life.

Industry instability Several industries depend on the groundwater to produce various products and keep running factories efficiently. If pH and quality of groundwater from a given area changes, the industries will be less capable to maintain stable production. This will affect the economy.

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5. Groundwater Contamination Controlling Regulations

Once water is contaminated, it is expensive, difficult, and sometimes impossible to remove contaminants. However, water contamination could be prevented by using some protection regulations to keep water clean and mitigate any further contamination. Some useful protection methods can be used such as:

1. Containing the contaminant to stop migration. 2. Treating the water after pumping it, and returning it to the aquifer. 3. Treating the ground water in place or treating the contaminant. 4. Allowing the contaminant to reduce naturally with monitoring, following the

implementation of an appropriate source control. 5. Some technologies to remove contaminants from groundwater can be used to

refine the water such as: [13] a) Air stripping:

This process involves pumping out the contaminated water, then heating it to evaporate the contaminant. The cleaned water is reinjected into the ground. Pumping out contaminated water and absorbing the pollutant on activated charcoal can remove less volatile compounds. [13]

b) Granular activated carbon: Activated carbon is commonly used to adsorb natural organic compounds, taste and odor compounds, and synthetic organic chemicals in drinking water treatment. Adsorption is both the physical and chemical process of accumulating a substance at the interface between liquid and solids phases. Activated carbon is an effective adsorbent because it is a highly porous material and provides a large surface area to which contaminants may adsorb. [14]

c) Advanced Oxidation Advanced oxidation processes are a set of chemical treatment procedures designed to remove organic and sometimes inorganic materials in water and waste water by oxidation through reactions with hydroxyl radicals. [15]

Preventing contamination is apparently important. Drinking water suppliers have

discovered that watershed protection is cost-effective because it reduces contamination and reduces the cost of drinking water treatment. A watershed is the area that drains into surface or groundwater and keeping that area free from development and agricultural runoff are among the goals of watershed protection. [14]

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groundwater treatment techniques can be mainly divided into two technologies as following: [16]

Ex-Situ Technology Extraction of groundwater from aquifer, treat above ground. and return the treated water to the aquifer. Extraction is done by pumping groundwater from the well or trench and treat them.

Fig. 7 Ex-Situ Remediation Technology [16]

In-Situ Technology involves treatment of ground water within the aquifer in the sub-surface by using thermal, chemical and biological treatment technologies.

Fig. 8 In-Situ Remediation Technology [16]

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Groundwater treatment techniques are not only limited to chemical and biological mechanisms, but the best way is preventing water to contaminate in the first place. The following ways could be insured and carried out by businesses and industries which can decrease the contamination hazards: [17]

1. Install groundwater observation systems such as leak detection and repair systems 2. Reduction of the usage of toxic or hazardous raw materials. 3. Maintain storage tanks and pipelines to prevent leaks that leach to the groundwater. 4. Contaminants must be disposed, handled, and transported appropriately. 5. Landfills must be regulated and discharged and continuously monitored by local

authorities. 6. Get involved in water education for students to learn more about groundwater and

share knowledge with others. 7. The community can contribute severely to groundwater contamination beside the

industrial activities, but there should be effective steps by individual households to minimize these affects such as: Cleaning chemicals that contain toxic substances should not be used

extensively. Drain chemicals, insecticides and motor oil should not be disposed in

community areas. paints, pesticides, detergents, and polishing materials should be properly

disposed of.

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6. Conclusion and Recommendations

This research provided the baseline information on the groundwater contamination. It was found that groundwater is very important source of fresh water and that makes the contamination prevention is an important action by the government or any related authorities or organizations. The sources of groundwater contamination are various and may cause contamination without any clear evidence of the contamination, so this will lead to further contamination spreads widely in the same area.

The sources of groundwater contamination were mentioned in this research with detailed description of their origins and effects on the groundwater. There are many classifications that could be used for classifying the groundwater contaminants as discussed in this research, depending on the types of materials and any activities causing groundwater contamination.

The effects of groundwater contamination are clear and widely known for local organization or even individuals, so that will be helpful preventing further groundwater contamination. However, lots of violations could surely lead to more severe groundwater contamination in the unregulated areas. Health effects are the most hazardous effects of groundwater contamination and they are resulted from the wrong usage of groundwater without any testing or curing before using it for drinking or other purposes.

The groundwater is a very important source for domestic use and also for industrial purposes. This important source should be maintained clean and any potential source of contamination should be prevented at first. There is a common rule said that “the best way to deal with groundwater contamination is not to contaminate it in the first place”.

Very strict regulations should be admitted to secure the use of groundwater in cities or rural areas. Extensive monitoring by professionals must be funded to study the current situation of available sources of groundwater and measure the actual contaminated water, then suggesting solutions for both treatment and prevention of further contamination.

Local organizations should carry out very specialized studies on the groundwater sources, in addition to aware the residents about the importance of water and the right methods of dealing with the water sources. Educational activities also could be useful enhancing the awareness of the young generation about the water sources of their future.

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References

1. West, Larry "World Water Day: A Billion People Worldwide Lack Safe Drinking

Water." About News. (Accessed on 05 December 2016)

<http://environment.about.com/od/environmentalevents/a/waterdayqa.htm>.

2. "China says water pollution so severe that cities could lack safe supplies” China

Daily. 07 June 2005. (Accessed on 04 December 2016)

<http://www.chinadaily.com.cn/english/doc/2005-06/07/content_449451.htm>.

3. Kahn, Joseph and Yardley, Jim "As China Roars, Pollution Reaches Deadly

Extremes” The New York Times. 26 August 2007. (Accessed on 04 December 2016)

<http://www.nytimes.com/2007/08/26/world/asia/26china.html>.

4. "What Is Ground Water?” U.S. Geological Survey. U.S. Department of the Interior.

01 September 2007. (Accessed on 04 December 2016) <

http://pubs.usgs.gov/of/1993/ofr93-643/>.

5. "Water Resources Management: Groundwater” The World Bank. (Accessed on 04

December 2016) < http://go.worldbank.org/6YTISD5KR0>.

6. "Water pollution” Wikipedia, The Free Encyclopedia. 2 December 2016. (Accessed

on 04 December 2016) < https://en.wikipedia.org/wiki/Water_pollution >.

7. " Groundwater Contamination” The Groundwater Foundation. (Accessed on 04

December 2016) <http://www.groundwater.org/get-

informed/groundwater/contamination.html>.

8. “Groundwater Contamination” US Environmental Protection Agency. (Accessed on

05 December 2016) <https://www.epa.gov/sites/production/files/2015-

08/documents/mgwc-gwc1.pdf>.

9. Hogan, C Michael “Water pollution” The Encyclopedia of Earth. 17 November 2014.

(Accessed on 05 December 2016)

<http://editors.eol.org/eoearth/wiki/Water_contamination>.

10. “The effects of groundwater pollution” Groundwater Pollution. (Accessed on 05

December 2016) <https://sites.google.com/site/rhschem5aharley/effects-of-

groundwater>.

11. “Groundwater Contamination” Worst Pollution Problems. (Accessed on 05

December 2016) <http://www.worstpolluted.org/projects_reports/display/58>

Page 17: Ground water contamination

17

12. “The Causes and Effects of Groundwater Contamination” All About Water Filters.

(Accessed on 05 December 2016) < http://all-about-water-filters.com/causes-effects-

groundwater-contamination/>.

13. “Water Pollution: Freshwater” Pollution Issues. 04 January 2007. (Accessed on 05

December 2016) <http://www.pollutionissues.com/Ve-Z/Water-Pollution-

Freshwater.html>.

14. “Granular Activated Carbon” Environmental Protection Agency. (Accessed on 06

December 2016)

<https://iaspub.epa.gov/tdb/pages/treatment/treatmentOverview.do?treatmentProcess

Id=2074826383>.

15. “Advanced oxidation process” Wikipedia, The Free Encyclopedia. 4 October 2016.

(Accessed on 06 December 2016)

<https://en.wikipedia.org/wiki/Advanced_oxidation_process>.

16. Glaze, William; Kang, Joon-Wun; Chapin, Douglas H. (1987). "The Chemistry of

Water Treatment Processes Involving Ozone, Hydrogen Peroxide and Ultraviolet

Radiation.". Ozone: Science & Engineering.

17. Ismail S.A, Dr. Mohamed “Preventive Measures and Remedial Techniques for

Groundwater Contamination” The Royal Commission Environmental Project. 27

May 2012. (Accessed on 06 December 2016) <

http://www.slideshare.net/najamulhassan52/15-groundwater-contamination-

prevention-and-remedial-techniques-as-on-27052012-new-design>.

18. “Preventing Groundwater Contamination” Groundwater Treatment and

Technology, LLC. (Accessed on 05 December 2016)

<http://www.gwttllc.com/about-gwtt-inc/blog/449-preventing-groundwater-

contamination>.