We are living in a time of rising public awareness of environmental degradation
and public quality of life concerns.
These include concerns about the global deterioration of air quality,
water quality, soil productivity and security of food supplies.
Of all of these areas of concern, water represents one of the most
rapidly challenged critical resources in the world.
While water is abundant, 97.7% of all waters are salty or unfit for use.
Of the remaining 2.5%, 1.5% are trapped underground or in ice caps, or
are present as soil moisture.
Overall, less than 1% of the earth’s water is available for direct use, with
agriculture and industry accounting for 80% of water use globally.
About half of available water comes from groundwater sources (wells,
aquifers,) and half from other surface sources such as rivers and lakes and
rainwater. Globally, there is a
pressing need for infrastructure which can ensure safe supplies of drinking
water well into the future. Global
infrastructure needs over the next 25 years are estimated to approach $20
trillion worldwide.
Water quality and safety are affected by a variety of contaminants, including
organic and inorganic chemicals, heavy metals, petrochemicals, chloroform, and
bacteria. Principal stationary
sources of risk to water quality and safety include chemical plants, coal-fired
power plants, oil refineries, nuclear waste disposal activity, incinerators,
large animals farms, PVC factories, metals production factories, plastics
factories and other heavy industry.
Typically these industries use large amounts of water in their processes, and
these processes produce effluent that requires treatment in order to safeguard
supplies of drinking water from point-source pollution.
Water contamination can also be a consequence of a natural disaster.
For example, hurricanes often involve water contamination from sewage
spills or from petrochemical spills from ruptured boats or automobiles.
Naturally occurring contaminants in rocks and sediments call also affect
water quality and safety. As ground
water drains through rocks and soil, metals such as iron and manganese can
become concentrated in ground water.
Soil contamination from industrial and agricultural sources is also another risk
factor that goes hand-in-hand with water contamination.
Common soil contaminants include:
chlorinated hydrocarbons, heavy metals such as lead (found in paint and,
until not that long ago, in gasoline) and mercury, MTBE, cadmium (from
rechargeable batteries), chromium, zinc, arsenic and benzene.
For example, the Czech Republic has an area of approximately 300,000
metric tons of soil with 1% of mercury contamination.
France has 47, 000 metric tons of soil contaminated with 0.89% mercury.
Ordinary municipal landfills can also be a source of many chemical
substances entering the soil environment, particularly pre-1970 landfills that
may have been subject to little environmental control, and from the variety of
waste materials collected at landfills
(eg. batteries, computers).
As groundwater moves through rock and subsurface soil, it has ample
opportunity to capture, dissolve and retain many of these substances.
For this reason, ground water will often have many more of these
contaminants than surface
water. In Canada, 30.3% of
domestic water use comes from groundwater sources, and in the United States, 49%
of water use comes from groundwater.
These averages vary depending on the area of the country being addressed.
In Prince Edward Island, for example, 100% of water supplies come from
groundwater, and in New Brunswick 60% of the population depends on groundwater
for domestic water supplies.
(Sources: Saylac.com; “ Decade of
Challenge Report”, Industry Canada; Reuters Alert, March 5, 2007; Van Eck Global
Environmental Services Index Report, 4th Quarter 2006;
Crystallinks.com; “Groundwater – Nature’s Hidden Treasure”, Environment Canada,
1999; U.S Department of the Interior, U.S. Geological Survey)