8 Reappraisal of Permeable Reactive Barrier as a Sustainable …
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8.2 Groundwater Contamination
Sources
Groundwater contamination has been mostly due to human activities but also some
part of it is due to the naturally occurring minerals. The contaminants once produced
due to any anthropogenic activities leak down the aquifer pollute the groundwater,
and it becomes very difficult as well as costly to remediate. The conventional remediation technologies like the pump and treat systems used to have high operational
and maintenance costs. The contaminants according to their physical, chemical or
biological nature sometimes travel with the flow of groundwater, sometimes they do
not, forming a contaminated plume.
The sources of groundwater contamination can be broadly divided into two main
categories
1. Natural Sources
2. Anthropogenic Sources
(a) Point Sources
(b) Non-Point Sources.
If you walk through a mountain valley and you see a cascading river stream, which
may seem clear at first but same may not be the case, it would have been contaminated
with naturally occurring minerals like hydrogen sulfide (H 2 S), chromium (Cr(VI)),
arsenic (As), iron (Fe), fluorides (F), radon gas (Rn), etc., which generally comes
from the disintegration of Uranium (U), another natural radioactive contaminant.
Anthropogenic sources include Pointy and Non-Point sources. Point sources include
those sources which contaminate groundwater directly. It may include a varied range
of sources from leaking chemical tanks or septic storage tanks situated just below the
ground. On the other hand, Non-Point sources include sources which do not pollute
groundwater directly but usually due to the runoff from a contaminated site. These
contaminated sites include an agricultural field where pesticides and fertilizers are
sprayed regularly or the chemical factories where the pollutants are not disposed of
properly or untreated. There are a new set of contaminants coming into the picture
of groundwater contamination known as ‘Emerging Organic Contaminants’ (EOCs),
and these include pharmaceutical products, body care products also known PPCP.
These are the contaminant usually present in the range of (ng/L or µg/L) (Lapworth
et al. 2012). These contaminants are not only lacking a proper categorization but also
do not have enough data, to make a universal decision for their permissible limits.
Till 2012, there were more than 180 EOCs detected in groundwater.
Coming to India, it has a varied range of hydrogeological conditions which is a
result of different amount of pattern of rainfall, wide range of geological conditions
and also the topographical features in the entire county, the natural contaminants like
fluoride, arsenic, chlorides vary vividly throughout the entire country, for example,
there is high arsenic concentration in eastern states and high fluoride concentrations
in western states of India. The various contaminants exceeding the permissible WHO
181
8.2 Groundwater Contamination
Sources
Groundwater contamination has been mostly due to human activities but also some
part of it is due to the naturally occurring minerals. The contaminants once produced
due to any anthropogenic activities leak down the aquifer pollute the groundwater,
and it becomes very difficult as well as costly to remediate. The conventional remediation technologies like the pump and treat systems used to have high operational
and maintenance costs. The contaminants according to their physical, chemical or
biological nature sometimes travel with the flow of groundwater, sometimes they do
not, forming a contaminated plume.
The sources of groundwater contamination can be broadly divided into two main
categories
1. Natural Sources
2. Anthropogenic Sources
(a) Point Sources
(b) Non-Point Sources.
If you walk through a mountain valley and you see a cascading river stream, which
may seem clear at first but same may not be the case, it would have been contaminated
with naturally occurring minerals like hydrogen sulfide (H 2 S), chromium (Cr(VI)),
arsenic (As), iron (Fe), fluorides (F), radon gas (Rn), etc., which generally comes
from the disintegration of Uranium (U), another natural radioactive contaminant.
Anthropogenic sources include Pointy and Non-Point sources. Point sources include
those sources which contaminate groundwater directly. It may include a varied range
of sources from leaking chemical tanks or septic storage tanks situated just below the
ground. On the other hand, Non-Point sources include sources which do not pollute
groundwater directly but usually due to the runoff from a contaminated site. These
contaminated sites include an agricultural field where pesticides and fertilizers are
sprayed regularly or the chemical factories where the pollutants are not disposed of
properly or untreated. There are a new set of contaminants coming into the picture
of groundwater contamination known as ‘Emerging Organic Contaminants’ (EOCs),
and these include pharmaceutical products, body care products also known PPCP.
These are the contaminant usually present in the range of (ng/L or µg/L) (Lapworth
et al. 2012). These contaminants are not only lacking a proper categorization but also
do not have enough data, to make a universal decision for their permissible limits.
Till 2012, there were more than 180 EOCs detected in groundwater.
Coming to India, it has a varied range of hydrogeological conditions which is a
result of different amount of pattern of rainfall, wide range of geological conditions
and also the topographical features in the entire county, the natural contaminants like
fluoride, arsenic, chlorides vary vividly throughout the entire country, for example,
there is high arsenic concentration in eastern states and high fluoride concentrations
in western states of India. The various contaminants exceeding the permissible WHO