the ecosystem. Beyond doubt, the reason of existence of life on earth is the presence
of water and in fact some theories even suggest that the life originated in water
[1, 2]. Water happens to be the key necessity for us, as well as, for the marine and
aquatic life and hence any non-natural additives to it leads to the disturbance in the
ecosystem balance. Therefore, it is vital to protect the water from being polluted and
contaminated for the survival of the human race. In order to achieve this, the first
and foremost step is to identify or sense the existence of the contaminants or
pollutants in water, followed by taking remedial action for its rectification and
purification. Hefty amounts of money are being spent on water remediation around
the globe and still a lot needs to be done.
Water can become contaminated through multiple sources of impurities. These
can be of industrial origin, agricultural or due to human interventions. Some of the
common impurities are heavy metals ions (lead, arsenic, chromium, mercury and
cadmium), hydrocarbons, organic compounds (volatile organic compounds, phenols and dioxins), dissolved toxic gases like sulfur dioxide, nitrogen oxides, particulates, organophosphorus (OP) compounds (pesticides and insecticides), and
biological impurities like pathogens [3–5]. All of these ultimately can damage the
ecosystem and are unfavorable for the human health and environmental security.
Long term exposure to heavy metal and particulate matter is a significant leading
factor in causing health problems in the form of various diseases, while on other
hand it can cause many disorders in ecological environments (including plant and
animal life) and tend to affect the food chains [5, 6]. The heavy-metal accumulates
slowly in human bodies and causes various chronic diseases. Therefore, it is
imperative to develop economical, sensitive, selective, and simple detection
methods to monitor and ultimately remediate these toxic substances from water.
Organic pollutants and biological impurities in water also needs to be regulated.
The effect of presence of coliforms and pathogens in water leads to many disease
like diaorrhea, urinary tract infections and respiratory disorders [7–9]. Organic
pollutants on the other hand are more dangerous to aquatic life but can enter human
body through these sources. They can lead to cancer risk, reproductive and
immunological disorders, neuro-impairment, genotoxicity and increased birth
defects. World Health Organization(WHO) has laid down specific guidelines for the
control of all water specific pollutants and contaminants [10].
There are a variety of techniques available for identification of water pollutants,
such as surface plasmon resonance (SPR) [11, 12], gas chromatography-mass
spectrometry (GC-MS) [13, 14], high-performance liquid chromatography (HPLC)
[15, 16], inductively coupled plasma mass spectrometry (ICP-MS) [17]. However,
many of these are either expensive or time-consuming and require complicated
sample preparation. For optimal utilization, the sensing methodology needs to be
extremely specific, and suitable for day to day or even field monitoring of water
pollutants. We can increase the incidences of contaminant monitoring and process
control only if the available detection technology is sensitive, selective and less
expensive. In recent years, many different kinds of sensors have been developed for
chemical and biological water pollutant detection. The target is to achieve ease of
fabrication, low-cost, high sensitivity and selectivity for sensors. The role of
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A. K. Srivastava et al.
of water and in fact some theories even suggest that the life originated in water
[1, 2]. Water happens to be the key necessity for us, as well as, for the marine and
aquatic life and hence any non-natural additives to it leads to the disturbance in the
ecosystem balance. Therefore, it is vital to protect the water from being polluted and
contaminated for the survival of the human race. In order to achieve this, the first
and foremost step is to identify or sense the existence of the contaminants or
pollutants in water, followed by taking remedial action for its rectification and
purification. Hefty amounts of money are being spent on water remediation around
the globe and still a lot needs to be done.
Water can become contaminated through multiple sources of impurities. These
can be of industrial origin, agricultural or due to human interventions. Some of the
common impurities are heavy metals ions (lead, arsenic, chromium, mercury and
cadmium), hydrocarbons, organic compounds (volatile organic compounds, phenols and dioxins), dissolved toxic gases like sulfur dioxide, nitrogen oxides, particulates, organophosphorus (OP) compounds (pesticides and insecticides), and
biological impurities like pathogens [3–5]. All of these ultimately can damage the
ecosystem and are unfavorable for the human health and environmental security.
Long term exposure to heavy metal and particulate matter is a significant leading
factor in causing health problems in the form of various diseases, while on other
hand it can cause many disorders in ecological environments (including plant and
animal life) and tend to affect the food chains [5, 6]. The heavy-metal accumulates
slowly in human bodies and causes various chronic diseases. Therefore, it is
imperative to develop economical, sensitive, selective, and simple detection
methods to monitor and ultimately remediate these toxic substances from water.
Organic pollutants and biological impurities in water also needs to be regulated.
The effect of presence of coliforms and pathogens in water leads to many disease
like diaorrhea, urinary tract infections and respiratory disorders [7–9]. Organic
pollutants on the other hand are more dangerous to aquatic life but can enter human
body through these sources. They can lead to cancer risk, reproductive and
immunological disorders, neuro-impairment, genotoxicity and increased birth
defects. World Health Organization(WHO) has laid down specific guidelines for the
control of all water specific pollutants and contaminants [10].
There are a variety of techniques available for identification of water pollutants,
such as surface plasmon resonance (SPR) [11, 12], gas chromatography-mass
spectrometry (GC-MS) [13, 14], high-performance liquid chromatography (HPLC)
[15, 16], inductively coupled plasma mass spectrometry (ICP-MS) [17]. However,
many of these are either expensive or time-consuming and require complicated
sample preparation. For optimal utilization, the sensing methodology needs to be
extremely specific, and suitable for day to day or even field monitoring of water
pollutants. We can increase the incidences of contaminant monitoring and process
control only if the available detection technology is sensitive, selective and less
expensive. In recent years, many different kinds of sensors have been developed for
chemical and biological water pollutant detection. The target is to achieve ease of
fabrication, low-cost, high sensitivity and selectivity for sensors. The role of
300
A. K. Srivastava et al.