Hydraulic Fracturing

Hydraulic fracturing is a process of fracturing rock with the help of mixed fluid pressurization to obtain gas from the shale. Shallow wells have limitations of gas production due to low permeability of sedimentary rock containing gas. Hydraulic fracturing facilitates the fluids to flow in the rock and production of gas from the shale (Arthur and Coughlin, 2008).

Water based fluids are the most common fracturing fluid however foam based, oil based, acid based, alcohol based and emulsion based fluids can be used in hydraulic fracturing (Gandossi, 2013). Enormous amount of freshwater is needed in fracturing process and the waste water has to be treated before releasing into the environment. Fracturing processing may increase the risk of drinking water contamination of the adjacent areas. Environmental risks such as methane pollution, air pollution impacts, blowouts due to gas explosion, fracking-induced earthquakes may be associated with hydraulic fracking and production of gas (Hoffman, J., 2012).

Toxic chemicals used during the fracturing process and release of toxic and radioactive chemicals are detrimental to the environment (networkforphl.org, n.d.). Chemicals such as hydrochloric acid, ammonium chloride, ammonium persulfate, isopropanol, formic acid, potassium metaborate, triethanol -amine zirconate, methanol, citric acid, lauryl sulfate, naphthalene are used in the mixed fracturing fluid (fracfocus.org, 2015). Chemicals used in the fracturing process acts as clay stabilizer, breaker, biocide, cross- linker, friction reducer, gelling agent, iron control, pH adjusting agent, scale inhibitor and surfactant (fracfocus.org, 2015). Shales containing organic acids, volatile organic compounds, trace elements such as mercury, lead and arsenic and radioactive elements such as radium, thorium and uranium can be released into the environment (networkforphl.org, n.d.).


Arthur, J.D. and Coughlin, B.J. (2008) Evaluating the Environmental Implications of Hydraulic Fracturing in Shale Gas Reservoirs [Online] Available at http://www.all-llc.com [Accessed on 23 February 2015].

FracFocus (2015) What Chemicals are Used [Online] Available at http://www.fracfocus.org [Accessed on 23 February 2015].

Gandossi, L. (2013) An Overview of Hydraulic Fracturing and other Formation Stimulation Technologies for Shale Gas Production [Online] Available at http://www.ec.europa.eu [Accessed on 23 February 2015].

Hoffman, J. (2012) Potential Health and Environmental Effects of Hydro fracturing in the Williston Basin, Montana [Online] Available at http://www.carleton.edu [Accessed on 23 February 2015].

Network for Public Health Law (n.d.) Environmental Impacts Associated with Hydraulic Fracturing Available at http://www.networkforphl.org [Accessed on 23 February 2015].


Health Effects of Cadmium

Presence of cadmium in drinking water is hazardous to human health. Renal, cardiovascular, respiratory and skeletal effects have been found to be induced by cadmium exposure. Cadmium can induce renal tubular dysfunction leading to renal lesion and irreversible impairment of reabsorption capacity of renal tubules. Combine concentration of metallothionein, a cadmium binding protein, and cadmium can be found in the renal cortex of Kidneys (Queensland Health, 2002). Increased excretion of low molecular weight proteins such as B2-microglobulin and alpha1-microglobulin and enzymes such as N-acetyl-B-D-glocosaminidase (NAG) or tubular proteinuria may be caused by exposure to cadmium (Jarup, 2003; WHO, 2011). Destroyed arrangement of mineral metabolism and nutritional deficiencies are associated with accumulation of cadmium in the Kidneys (Queensland Health, 2002).

Kidney stones have been associated with cadmium. Renal damage and conditions such as hypercalciuria and hyperphosphateuria may result kidney stone (CDC, 2013). Skeletal damage, osteomalacia or osteoporosis might occur as a result of long term exposure to Cadmium (Jarup, 2003; WHO, 2011). Many cases of skeletal disease also known as itai-itai disease was reported in Japan in the 1950s due to long term exposure to cadmium in drinking water (Jarup, 2003; WHO, 2011).

Respiratory disease and bone disease could be resulted due to long term (20-30 years) accumulation of cadmium in Kidney (ICdA, n.d.). Stomach irritation, vomiting and diarrhoea could be resulted from drinking water with high levels of cadmium (Illinois Department of Public Health, n.d.; Queensland Health, 2002). Illinois Department of Public Health (n.d.) suggested the probability of low birth weight babies for women exposed to cadmium. Suppression of testicular function could be induced by Cadmium toxicity (Queensland Health, 2002).


Centres for Disease Control and Prevention (CDC) (2013) Cadmium Toxicity: What Diseases are Associated with Chronic Exposure to Cadmium [Online] Available at www.cdc.gov [Accessed on 09 January 2015].

Illinois Department of Public Health (n.d.) Environmental Health Fact Sheet [Online] Available at www.idph.state.il.us [Accessed on 5 January 2015].

International Cadmium Association (ICdA)(n.d.) Cadmium Exposure and Human Health [Online] Available at www.cadmium.org [Accesses on 5 January 2015].

Queensland Health (2002) Cadmium [Online] Available at www.health.gld.gov.au [Accessed on 5 January 2015].

World Health Organization (WHO) (2011) Cadmium in Drinking Water: Background Document for Development of WHO Guidelines for Drinking Water Quality [Online] Available at www.who.int [Accessed on 5 January 2015].


Antibiotics have been used in the treatment of various diseases.  However, development of drug resistance among various species of micro-organisms reduces the effectiveness of antibiotics. Centres for Disease Control (2013) identified drug resistant species such as  Clostridium difficile , Enterobacteriaceae, Neisseria gonorrhoeae  as urgent threats and acinetobacter, camphylobacter, candida, enterococcus, Pseudomonas aeruginosa, Salmonella, Shigella, Staphylococcus aureus  and Staphylococcus pnuemoniae  as serious threats to human health in USA.

Nanotechnology in drug administration and use of nanobiotics has been found to be more effective in drug resistant infection control and cancer treatment (Moodley, n.d.). Nanomaterials are particles of diameter between 1 to 100 nm which are capable of circulating human body, cells and blood vessels (European Agency, n.d.). Nanobiotics or the nanomaterials containing drugs are more effective in diagnosis, monitoring, treatment and prevention of diseases.

Nanomaterials such as silver, zinc oxide, titanium dioxide, gold chitosan, fullerenes, carbon nanotubes, quantum dots, dendrimers, liquid based nanoparticles, ceramic nanoparticels and nitric-oxide releasing nanoparticles can be applied as nanobiotics in the treatment of diseases (Moodley, n.d.). Crystalline nanoparticles can be used in X-ray based cancer treatment (understandingnano.com, 2009). Peptide rings, 2.5 nm rings of customised amino acids, have been found to be operative in tackling with staphylococcus aureus, a drug resistant bacterium (Mason, 2001).

Adverse side effects could be associated with nanobiotic treatment. Nanomaterials could induce inflammation, tissue damage, oxidative stress, chronic toxicity, cytotoxicity, fibrosis and tumer generation (European Agency, n.d.). Development and application of nanobiotic drugs and minimization of adverse effects will minimize the health complications associated with drug resistant micro-organisms.


Centres for Disease Control (CDC) (2013) Antibiotic Resistance Threats in the United States, 2013 [Online] Available at www.cdc.gov [Accessed on 26 January 2015].

European Agency for Safety and Health at Work (n.d.) Nanomaterials in the Healthcare Sector: Occupational Risk and Prevention [Online] Available at http://www.osha.europa.eu [Accessed on 25 January 2015].

Mason, J. (2001) Nanobiotic Life Saver [Online] Available at http://www.technologyreview.com [Accessed on 26 January 2015].

Moodley, N. (n.d.) Antimicrobial Activity of Ciprofloxacin-coated Gold Nanoparticles on Selected Pathogens [Online] Available at http://www.dut.ac.za  [Accessed on 25 January 2015].

Understandingnano.com (2009) Nanoparticles for Enhanced X-ray treatment of Cancer Tumours [Online] Available at http://www.understandingnano.com [Accessed on 26 January 2015].

Cadmium in Drinking Water

Heavy metals, metals with specific density of more than 5 gm/cm3, have been used in everyday applications. Human exposure to heavy metals has immediate health concerns. Lead, Cadmium, Mercury, and Arsenic were identified as major threats to human health (Jarup, 2003). Cadmium has been commercially used in PVC products, colour pigment, alloys, rechargeable nickel-cadmium batteries and anti-corrosion agent (IFC, 1998; Jarup, 2003). Drinking water can be contaminated with Cadmium, caused by impure galvanized pipes and cadmium-containing solders in fittings, water heaters, water coolers and taps (WHO, 2011).

Cadmium is highly toxic, non-degradable and persistent element (Rao et al., 2010). Toxic form of Cadmium is free Cadmium divalent ion however other forms such as organic and inorganic ligands may produce adverse health effects (Environment Canada, 2014). Hydrated ion, inorganic and organic complex forms of Cadmium can be found in surface and ground water.  Behaviour of Cadmium in water is affected by pH, hardness, alkalinity, oxidation reduction potential and type and abundance of organic ligands and hydroxides (Environment Canada, 2014). Toxicity of Cadmium is highly influenced by water hardness, the lower the water hardness the lower the toxicity of Cadmium (Environment Canada, 2014).

Causative factors for Cadmium pollution in water include mine water from mine tailings, process water from smelters, phosphate mining and electroplating wastes (IFC, 1998). Diffuse cadmium pollution is mainly caused by fertilizers produced from phosphate ores (WHO, 2011). Soil cadmium contamination is produced from industrial emissions and the application of fertilizer and sewage sludge to farm land (Jarup, 2003). Various pollutants removal technologies can be applied to remove cadmium from drinking water. Chemical precipitation, ion exchange, cementation, solvent extraction, membrane separation and adsorption are available technologies for the removal of cadmium from water (Rao et al., 2010).


Environment Canada (2014) Canadian Water Quality Guidelines for the Protection of Aquatic Life [Online] Available at www.ceqg-rcqu.ccme.ca [Accessed on 23 December 2014].

International Finance Corporation (IFC)(1998) Cadmium [Online] Available at www.ifc.org [Accessed on 23 December 2014].

Jarup, L. (2003) Hazards of Heavy Metal Contamination. British Medical Bulletin, Vol 68 (1), pp 167-182.

Rao, K.S., Mohapatra, M., Anand, S and Venkateswarl, P. (2010) Review of Cadmium Removal from Aqueous Solutions. International Journal of Engineering, Science and Technology, Vol 2 (7), pp 81-103.

World Health Organization (WHO)(2011) Cadmium in Drinking Water: Background Document for Development of WHO Guidelines for Drinking Water Quality. [Online] Available at http://www.who.int [Accessed on 23 December 2014].

Super Resolution Fluorescence Microscopy

Eric Betzig, Stefan W. Hell and William E. Moerner were jointly awarded 2014 Nobel Prize in Chemistry for the development of super- resolved fluorescence microscopy. Microscope has been used as a powerful scientific instrument in the study of cell, cell biology and cellular functions. Cellular structure and objects occurs in the size range of tens to few hundreds nano meters however conventional light microscopy is only capable to handle cellular structure that are 200 to 350 nm apart (Schermelleh et al., 2010). Super resolution microscopy resolves more cellular structure at the macromolecular level.  Electron microscopy can resolve molecular and atomic structures with smaller wavelengths of electronic beam however energies of electrons have been found to be destructive for biological samples (Aguet, 3009)

Point spread function (PSF) can be defined as “the fixed size of the spread of a single point of light that is diffracted through a microscope” (Galbraith and Galbraith, 2011). Higher resolution microscopy helps to study smaller cellular structures than the PSF size of conventional microscopes. Cellular objects which are closer than PSF width of microscope appears as a single objects. Galbraith and Galbraith (2011) defined super-resolution microscopy as a technique which has at least double PSF width value than conventional microscopy.

Fluorophores are the molecules with an ability to fluoresce and fluorescence is the phenomenon where fluorophore emits light (Aguet, 2009). Fluoroscence microscopy has been used to distinguish cellular structure and specific protein by marking them (Aguet, 2009). Super resolution fluorescence microscopy has been used to study structures and functions of sub-cellular components and dynamic processes within the cell.


Aguet, F. (2009) Super-Resolution Fluoroscence Microscopy Based on Physical Models [Online] Available at www.bigwww.epfl.ch [Accessed on 21 November 2014].

Galbraith, C.G. and Galbraith, J.A. (2011) Super-Resolution Microscopy at a Glance. Journal of Cell Science, Vol 124, pp 1607-1611.

Schermelleh, L., Heintzmann, R. and Leonhardt, H.  (2010) A Guide to Super-Resolution Fluoroscence Microscopy. JCB Review, Vol 190(2), pp 165-175.

Solar Windows

Solar technology has been used to produce heat and electricity. Solar PV panels are installed on the roof of a building to produce household energy. Solar technology can be applied as a solar window for energy production and conservation. Heat and energy exchange occurs through windows of a house in different ways. Non- solar heat losses and gains in the form of conduction, convection and radiation, solar heat gains in the form of radiation, ventilation and infiltration are possible pathways of energy exchange through windows (US Department of Energy, 2007).

Rate of transfer through the windows is measured as thermal transmittance or U-factor. Low U-factor of a window denotes less heat exchange through the windows which conserves energy allowing consistent and comfortable room temperature (NHPC, n.d.). Solar heat gains through the windows in the form of radiation is measured by Solar heat gain coefficient (SHGC) and lower the value of SHGC, lesser the amount of solar heat transmitted through the window(NHPC, n.d.).

Solar window technologies have been developed to improve the energy efficiency. Building-integrated photovoltaics (BIPV) technology uses a transparent solar panel with standard mono-crystalline PV cells (Martin, 2011). BIPV solar windows have lower U-value and generated energy using PV cells (Martin, 2011). Passive solar design techniques can be applied to new homes to collect and store solar heat passively. Passive solar de-sign includes direct gain or the application of transparent south facing windows to collect heat, indirect gain or the thermal storage of collected heat between the south-facing windows and the living spaces mostly using a Trombe wall and isolated gain or sunspace similar to greenhouse (US Department of Energy, 2001).


Martin II, J. (2011) Solar PV Windows: BIPV Technology by Pythagoras Solar [Online] Available at http://www.solarchoice.net.au [Accessed on 23 October 2014].

National Home Performance Council (NHPC) Understanding Energy Efficient Windows [Online] Available at http://www.nhpci.org [Accessed on 23 October 2014].

US Department of Energy (2001) Passive Solar Design for the Home [Online] Available at http://www.nrel.gov [Accessed on 23 October 2014].

US Department of Energy (2007) Selecting Windows for Energy Efficiency [Online] Available at http://www.windows.lbl.gov [Accessed on 23 October 2014].


Microorganisms can be used to degrade waste pollutants in bio-augmentation process. Bio- augmentation is a sustainable approach to pollutant remediation. Bio-augmentation is a mimic of natural process, it uses less energy, it releases less air pollutant and it helps to destroy the contaminants permanently (Environmental Expert, 2009). Effectiveness and affordability of bio augmentation, a powerful remediation measure, has been proved in the past few decades.

Pre-adapted native microbes or genetically modified microorganisms have been used in bio augmentation for pollution biodegradation (Nasseri et al., 2010).  Bacterial species such as Pseudomonas, Flavobacterium, Sphingobium, Alcaligens, Achromobacter, Rhodococcus, Mycobacterium, Bacillus and Fungal species such as Absidia, Achremonium, Aspergillus, Verticillium, Pencillium and Mucor have been applied to degrade pollutants (Gentry et al., 2004; Mrozik and Piotrowska-Seget, 2009).

Biodegradation of compounds such as nitrophenols, chlorinated solvents, methyl tert-butyl ether, oil, pentachlorophenol, polychlorinated biphenyls, polycyclic aromatic hydrocarbons and pesticides such as atrazine, dicamba and carbofuran has been carried out with microorganisms induced bio-augmentation (Gentry et al., 2004).  Effective bio augmentation technologies include cell culture, activated soil bio-augmentation, gene bio augmentation and phytoremediation (Gentry et al., 2004).

Factors such as contaminant concentrations, site hydro geochemical conditions, and competition with indigenous microorganisms, in situ growth, transport and decay of microbes affect the amount of microorganisms needed for remediation which ultimately affects the cost and performance associated with bio augmentation (Steffan et al., 2010). Temperature, moisture, pH, organic matter, aeration, nutrient content and soil type are determining factors for bio augmentation (Gentry et al., 2004; Mrozik and Piotrowska-Seget, 2009).


Cornelius, J. R. and Faigle, J.D. (2008) Bio-augmentation: An Effective Method for Reducing Contaminant Concentrations. [Online] Available at http://www.biovationenv.vom [Accessed on 11 October 2014].

Environmental Expert (2009) Bio-augmentation is a cost effective and sustainable remediation alternative [Online] Available at http://www.environmental-expert.com [Accessed on 23 October 2014].

Gentry, T.J., Rensing, C., Pepper, I.L. (2004) New Approaches for Bio-augmentation as a Remediation technology. Reviews in Environmental Science and Technology, Vol 34, pp. 447-494.

Mrozik, A. and Piotrowska-Seget, Z. (2009) Bio-augmentation as a Strategy for Cleaning up Soils Contaminated with Aromatic Compounds. Microbiological Research, Vol 165(5), pp. 363-375.

Nasseri, S., Kalantary, R.R., Nourieh, N., Naddafi, K., Mahvi, A.H. and Baradaran, N. (2010) Influence of Bio-augmentation in Biodegradation of PAHs-contaminated soil in Bio-Slurry Phase Reactor. Iran Journal of Environmental Health, Science, Engineering, Vol 7(3), p. 199-208.

Steffan, R., Schaefer, C. and Lippincott, D. (2010) Bio-augmentation for Groundwater Remediation [Online] Available at http://www.clu-in.org [Accessed on 12 October 2014].

Ecological Footprint

Various tools have been developed to quantify sustainability of cities and countries. Berger (2014) listed six aspects of sustainability as aesthetic, environmental, financial, functional, political and social. Environmental Sustainability of urban or rural area can be measured with ecological footprint. Calcott and Bull (2007) defined ecological footprint as “the amount of bio productive land and sea required supporting a person’s lifestyle”.

 Ecological footprint of a city can be calculated using individual’s requirement of productive land and sea using their current expenses in housing, transport, food, consumer items, private services, public services, capital investment and miscellaneous sectors (Calcott and Bull, 2007). Ecological footprint can be expressed in global hectares. Human consumption of resources equivalent to average productivity of global hectares is expressed in ecological footprint (IIED, 2006).

In 2007, global ecological footprint was about 1.5 times the earth’s bio-capacity (Lee and Peng, 2014). Significant difference can be observed between the ecological footprints of the continents. North America has an ecological footprint of 8.7 global hectares (gha) per person. In contrast, Africa has a footprint of 1.4 gha per person (Lee and Peng, 2014).

Urbanization has been identified as a triggering factor for larger ecological footprint as it increases resource consumption (WWF, 2014).  Calcott and Bull (2007) studied the ecological footprint of British cities and ranked them based on the number of plants required to meet current consumption trend. Newport and Plymouth have been ranked as number 1 requiring less resources (2.78 planets), London was ranked as 44 (3.05 planets) and Winchester was ranked as 60 (3.62 planets).


Berger, M. (2014) The Unsustainable City. Sustainability, Vol 6, pp. 365-374.

Calcott, A. and Bull, J. (2007) Ecological Footprint of British City Residents [Online] Available at http://www.wwf.org.uk [Accessed on 14 April 2014].

International Institute for Environment and Development (2006) Environment and Urbanization [Online] Available at http://www.sagepublication.com [Accessed on 14 April 2004].

Lee, Y and Peng, L (2014) Taiwan’s Ecological Footprint. Sustainability, Vol 6, pp 6170-6187.

World Wildlife Fund (WWF) (2014) Ecological Footprint and Sustainable Consumption in China. [Online] Available at http://www.wwfchina.org [Accessed on 24 October 2014].

Microbial Transport in Groundwater

Microbial contamination of groundwater could induce waterborne diseases such as hepatitis A, viral gastroenteritis, cholera, typhoid fever and giardiasis. Microbes being living organism, their transport in the groundwater is different than abiotic materials (Ginn et al., 2002). Physical processes such as advection, dispersion, straining, filtration, electrostatic and chemical process are responsible for microbial transport in groundwater (Ginn et al., 2002).

Microbial transport has been found to be controlled by hydrogeological heterogeneity of subsurface sediments (AGU, 2001). Various factors such as adhesion processes, filtration effects, physiological state of the cells, porous medium characteristics, water flow rates and intrinsic mobility of the cells determine the microbial transport activities (Newby et al., 2000).

Microbial transport is affected by the availability of pore space between soil particles. Size of the microbes should be smaller than micro pores for the filtration to occur. Nutrient availability affects the size of the microbes influencing microbial movement (Newby et al., 2000). Properties of cell surface and microbial adhesion influences microbial transport in the soil particles. pH value of the porous medium matrix solution has impacts on microbial transport (Newby et al., 2000). Viral adsorption and transport has been found to be affected by pH (Newby et al., 2000).

Ionic strength or the concentration of cations and anions in solution affects microbial transport. Decrease in ionic strength of the solution facilitates increased bacterial transport (Newby et al., 2000). Availability of cellular appendages such as pili, flagella, or fimbria and hydrological factors such as soil texture, soil structure, porosity, water content, and water movement affects microbial transport (Newby et al., 2000).  Pore water velocity and bacterial attachment to grain surface and detachment from grain surface controls the rate and extent of bacterial movement in groundwater (AGU, 2001).


American Geophysical Union (2001) Breakthroughs in Field Scale Bacterial Transport, Eos, Transaction, Vol 82(38), pp. 417, 423-425.

Ginn, T.R., Wood, B. D., Nelson, R. E., Scheibe, T.D., Murphy, E.M. and Clement, T.P. (2002) Processes in Microbial Transport in the Natural Subsurface, Advances in Water Resources, Vol 25, pp 1017-1042.

Newby, D.T., Pepper, I.L. and Maier, R.M. (2000) Microbial Transport [Online] Available at http://www.elesevier.com [16 August 2014]