Before we can discuss this in depth we must have an understanding of just what the contaminants are. Chemicals we have already hinted at but the following categories are provided to show how, what and where different contaminants fit into our environment. One must remember that the term "contaminant" applies to anything, hazardous to our health or not, that is found in water other than basic H2O.
1. Bacteria, Cysts, Algae, and Disease Producing Organisms of enteric [intestinal] origin. Simply put, these are living contaminants. As an example of origin, many members of the coliform group of bacteria have their beginning in the intestines of man. Billions of coliform organisms are excreted daily by man. They are as hardy or more so than disease organisms such as typhoid, cholera and dysentery bacteria. Algae is a common organism that most of us have seen or smelt. Due to its massive colonization in certain water conditions it becomes visible to the human eye. Cysts are complex forms of organisms that have developed "hardened outer skins" that are impervious to Ultraviolet light and most conventional disinfection chemicals. The outer skin breaks down when consumed by a human and the parasitic microbe produces a host of very alarming and serious symptoms.
2. Toxic and Chemical Contaminants. These can be resultant from organic and inorganic sources.
a. An inorganic source is any base element, such as those found naturally in nature e.g. Arsenic, Boron, Cadmium, Mercury, Asbestos, Chlorine etc.
b. Organic matter is that which is made up of organisms or formations of inorganics, such as plant life and man-made chemicals; Vinyl Chloride, Chloroform, 2-4-D, Diazinon, etc.
3. Colour. Usually resulting from water flushed from overflowing swamps.
4. Turbidity [cloudiness]. Generally caused by the erosion of clay deposits that are carried into suspension by the movement of the source water.
5. Odours and Tastes. These can be present due to the decomposition of organic matter but may also be the result of specific inorganic compounds found in ground water and algae formations in surface water.
6. Mineral Contamination. This can be in several forms, but the two most common conditions are identified below. These conditions generally occur in ground water supplies but an area such as the Great Salt Lakes would be an example of a surface supply with excessive saline contamination.
a. The presence of Carbon Dioxide enables water to take on calcium, magnesium, thus producing what we call commonly call "hard water".
b. Iron and Manganese. These are taken into solution in the absence of dissolved oxygen. They will form red and black precipitates when the water in which they are dissolved comes in contact with air. They may also give the water a metallic taste.
This topic will be discussed first by looking at surface water contamination and then ground water [aquifer] contamination. The focus is on the toxic and chemical contaminates. Most of the others are inorganic elements found naturally in nature and are generally adequately dealt with through conventional water treatment methods. Their existence does not threaten the livelihood of this planet and the hydrological cycle ensures their containment in specific geological locations.
Water needed for human consumption can be taken directly from streams and rivers or it can be extracted from natural stores of water in ponds and lakes. Ice and snow are also included in this category though the percentages of use are minimal in comparison to liquid supplies. As a result of an increasing population, expanding industry, greater agricultural and commercial activities, surface water contamination is increasing at alarming rates. The following descriptions will help you identify how this contamination takes place.
ACCIDENTAL SPILLS & LEAKS:
Our seemingly daily media coverage of this subject should have educated
you on this topic. Unfortunately most spills go undetected and many are
not accidental.
ACID RAIN:
The hydrological cycle that we described as "washing" the air
is a simplified version of how "acid rain" results. It should
now become clear how and why acid rain is affecting our whole planet not
just the heavy industrial areas. Precipitation that becomes laden with
chemical contaminants is constantly shifted around the globe by the winds.
When the precipitation finally falls it is indiscriminate of the location.
As the cycle continues the levels slowly increase.
AGRICULTURE ACTIVITY:
The vast quantities of pesticides, herbicides and fertilizers that
are deposited upon the farmers fields of today is staggering. There has
been a move towards "natural" products but until the effectiveness
and cost of these can compare with the chemical based products they will
be slow to catch on. As described earlier, natural rainfall and irrigation
washes the chemicals into the earth and eventually they find their way
into the aquifers and surface water supplies.
CYSTS:
GIARDIA [BEAVER FEVER]:
This is one of a host of complex parasitic microbes that can
be found in North American surface supplies. The microbes are transferred
between water sources by the faecal waste of animals. As the most common
in North America is by beavers, hence the nickname, "Beaver Fever".
The beaver is not affected by the microbe but humans become seriously ill.
The greatest danger is to small children and the elderly, as the "cure"
can be deadly to frail, weak or immature human systems. This is why nature/hiking/camping
books stress that you should never drink from "fresh" running
streams as you will never know who has "gone" in the water upstream.
BACTERIA and ALGAE:
Bacteria of one form or another is present throughout most all
water supplies but the concentrations are normally small. Marine life and
Ultraviolet light from the sun will normally control the levels. Waterborne
bacterial diseases have become less common with the advent of chemical
disinfection of our municipal water supplies, but they still exist and
in recent years they have once again affected many communities.
INDUSTRIAL DISCHARGE:
This is the waste from industry which is all too often deposited
directly into surface supplies. Companies are now having to put in their
own waste water treatment plants, but the few in existence are being proven
time and time again to still be inadequate. In many cases changes to the
government's "acceptable" levels has outdated the technology
in use by the companies and the agreements under which they were installed
forgive the companies from further compliance for many years to come.
LANDFILL OR SPREAD WASTE RUNOFF:
In the beginning, cities and municipalities picked dump sites
for their convenience, cost effectiveness and location to the population.
Precipitation that falls on these sites "washes" the chemicals
into the ground and as previously described, they eventually reach either
surface or ground water. Today, environmentalists have succeeded in demanding
that a proposed dump site be geologically examined in an attempt to locate
an area in which the earth formation is deemed impermeable to water passage.
This is so that the water and chemicals which percolate into the ground
from the waste, cannot escape into other ground water supplies. Further
to this, attempts are being made to limit the types of garbage that are
deposited in these sites. As the effectiveness of site will be determined
by the thoroughness of the geological survey, it is doubtful that even
these new sites will be positive barriers to the chemical threat.
MINING ACTIVITY:
Water has been used to act as a media for washing and transporting
different minerals during a mining process since mining began. The waste
water was not controlled and the increased levels of mineral contaminants
[inorganics] have destroyed the marine and plant life in the adjacent water
supplies. Controversy over this subject is at its peak with gold and petroleum
exploration coming under close review.
MUNICIPAL TREATMENT DISCHARGE:
Most communities have waste water treatment plants. These plants
are generally quite old and the technology that they apply was developed
to handle human faecal waste [bacteria], particulate matter and detergents.
The chemicals that are being deposited into the sewers of the 90's from
both industry and the public are well beyond their capacity. The costs
of new waste water technology are politically prohibitive because they
will result in a significant increase in taxes which would be burdened
on the general public. We all know how we hate taxes and politicians understand
the political suicide of introducing them. The issue of applying new technology
has received more funding for "studies" than "action"
in almost every community in North America. There have been studies of
the studies of the studies but it all boils down to the simply fact that
by funding a study, a politician can boast how he/she is taking these environmental
concerns in hand without introducing massive tax increases to fund an action
plan. We have no one to blame but ourselves.
NATURAL MINERAL CONCENTRATIONS:
Though these naturally occurring minerals are considered contaminates,
as described earlier, their presence in excessive amounts is generally
more annoying to our senses, appliances, and the ability to produce clean
laundry, than they are detrimental to our health. There are of course exceptions
to every rule. Some specific inorganics [e.g. arsenic, mercury etc.] must
be closely monitored and avoided.
PULP & PAPER WASTE DISCHARGE:
This industry because of the demand for "white" paper
has been bleaching wood fibres for years. Mills are located in areas close
to their source of trees. Rivers, lakes and the ocean have long been used
as the most economical transportation source for the timber. This adjacent,
inexpensive water source has been used in every facet of wood product production
and consequently all waste water discharge from the mills has been directly
deposited into the adjacent waters. Until recently there was no prior treatment.
This too is changing, but for government to condemn a mill or fine a corporation
to the point that it decides to close an operation, once again enters into
political suicide. If a mill closes a whole community can perish. The livelihood
of the working family still takes greater precedence than the consequences
to the environment.
ROAD DE-ICING CHEMICALS:
The harshness of our weather conditions has led us over the
years to use a wide range of chemicals on our roads. Once again our waste
water treatment systems are not equipped to handle these chemicals. Salt
being the predominant culprit.
STORM SEWERS:
Our treatment plants are geared to an anticipated flow rate
of sewage. Because mother nature deems fit to deposit excessive amounts
of precipitation upon our cities at unpredictable intervals, we have built
over flow systems to help control flooding of our precious homes. Each
time this happens, massive amounts of sewage and chemical runoff from many
of the topics listed above, bypass our exalted waste water treatment plants
and enter our water supplies directly.
We will begin with a more thorough description of groundwater. 97 percent of all the water on earth is in the oceans and 2 percent is frozen. Neither ocean water nor the frozen waters of the Polar Cap are available for use by man without extraordinary and very energy intensive technology. The remaining 1 percent equates to approximately 1,000,000 cubic miles of freshwater. Most of this is in the form of groundwater. Indeed, there is more groundwater in storage than in all the freshwater lakes and streams combined.
Ground water is an increasingly important resource, particularly in the USA, where about half of the freshwater consumed is from groundwater sources. It has become however, both an intentional and unintentional depository for society's waste and non-waste products.
Ground water is defined as subsurface water that occurs in fully saturated soils and geological formations. Ground water is an integral part of the "Hydrological Cycle". It is fed by surface water from wetlands, lakes, streams and the precipitation that infiltrates the ground and percolates down through the unsaturated soil formations to the "saturated" zones.
When the saturated layer of rock is sufficiently permeable to store and transmit significant quantities of water, the geological formation is called an "Aquifer". Aquifers can occur in packed formations of materials such as sand and gravel and consolidated materials such as bedrock. Sand and gravel aquifers usually contain the most ground water but high yield aquifers can also occur in bedrock.
The main difference between ground water and surface water is that the movement of groundwater is slow, streamlined and not turbulent. In its travels, ground water always takes the path of least resistance. A contaminant that has moved downward with soil moisture reaches the water table and then flows with the lay of the land, forward to a discharge point into a body of water, usually a lake, river or stream.
Contamination of ground water has recently become a hotly debated issue of public concern, primarily in the area of public health. Date limitations preclude a risk assessment on the magnitude of public health risks in existing ground water supplies. The U.S. government estimated in 1986 that close to 2 percent of the nation's ground water supplies were at least moderately polluted by 'point sources' such as hazardous waste dumps and leaking landfills. There are some 70,000 chemicals and compounds in existence today and approximately 1,000 new compounds are entering the marketplace each and every year. The Dow Chemical corporation, in its own publication in 1979, states that the company sets aside 90 percent of its available research dollars to developing pesticides and herbicides.
Summaries:
WASTE DISPOSAL SOURCES
NON WASTE DISPOSAL SOURCES
Each of these topics will be expanded upon in the following paragraphs. It must be pointed out that most all of the contamination topics described under surface water will affect ground water as well. Only the new sources will be expanded on here.
INDUSTRIAL SURFACE IMPOUNDMENTS:
A surface impoundment is commonly considered to be a pond, pool,
lagoon or pit used for the treatment, storage or disposal of wastes. Leaching
chemicals which percolate into the ground from these impounds eventually
find their way into ground water sources.
INJECTION WELLS:
The pressurized injection of liquid wastes, mainly of industrial
origin, has been widely adopted as a waste disposal practice in north America.
The intended purpose of this procedure is to isolate hazardous substances
from land and water, underground injection is not a cure-all for our hazardous
waste problems. There are significant limitations on the applicability
of underground injection for the disposal of hazardous wastes, based on
the types of wastes, the hydro-geology of the area and the construction
and operation of the injection well.
LAND DISPOSAL AND SPREADING OF WASTES:
There is no current data on the impact of these facilities on
ground water, the number of sites is staggering and almost uncountable.
We can conclude that the vast majority of private and municipal landfills,
contain waste that can be highly toxic. The exposure to precipitation combined
with open or leaching chemical waste, results in contaminants percolating
into the ground, making it all but certain that such facilities are major
sources of groundwater pollution and significant health threats.
MUNICIPAL WASTEWATER DISPOSAL:
Municipal wastewater [whether treated or not] is typically disposed
of into surface water sources. The water in these sources can be hydrologically
connected to neighbouring ground water through geological formation. It
can seep into underlying aquifers, carrying with it dissolved contaminants.
Hence, the potential exists for municipal wastewater to contaminate aquifers.
SUBSURFACE DISPOSAL SYSTEMS:
Approximately 20 million households [29%] use septic systems
or cesspools to dispose of their wastewater. The primary health hazard
is the introduction of bacteria and nitrates into ground water, but the
presence of organic cleaning solvents is a growing concern as well. The
problems associated with these systems are of a major concern in many areas;
often a substantial reliance on subsurface disposal systems is paralleled
by reliance on private drinking water wells. It is common in rural areas
to find the well on one man's land directly connected by means of a geological
formation to the septic field of another property owner. Bacteria and sediment
are contained by the geological formation and nature's "filtering"
takes place between the sites, but the odourless, tasteless and colourless
chemical deposits from the field move with the water to the well site.
ABANDONED AND LEAKY WELLS:
They provide a direct route for surface pollutants to enter
the underlying aquifer. Abandoned oil and gas wells can continue to discharge
brine, thereby contaminating shallow aquifers.
ACCIDENTAL SPILLS AND LEAKS:
covered under surface contaminants.
AGRICULTURAL ACTIVITIES:
covered under surface contaminants.
BURIED STORAGE TANKS:
Tanks that are used to store liquids of every description, including
gasoline, hazardous and toxic chemicals, domestic fuels, process chemicals
and wastes are often buried underground. There are millions of underground
storage tanks in North America and the experts calculate that between 75,000
to 100,000 are leaking right now. Local gas stations are an excellent example.
They only replace the tanks when they are suspected or proven to be leaking;
so just how many stations do you see under construction every year?
PETROLEUM EXPLORATION AND MINING:
The disposal of saline wastes in brine pits has been a major
cause of ground water contamination. Recently this activity was almost
universally banned after some 80 years of practice. Wastes from mining
activities typically contain nitrates, chlorides, heavy metals and radioactive
substances. Though banned, the existing pits will continue leaching for
generations.
SALT WATER ENCROACHMENT:
When too much water has been withdrawn from a freshwater supply,
saline water may be drawn into it from either the ocean or a neighbouring
saline aquifer. Once contaminated with saline the aquifer is useless for
generations, and possibly forever. Saline water contains a variety of minerals
and salts that can render an aquifer unfit for drinking or even irrigation
purposes.
DESIGN FLAWS - LEAD AND ASBESTOS
When copper plumbing was first introduced no one thought that
the lead in the solder would turn out to be a serious contamination problem
for the generations that were to follow. As the water sits warm and stagnant
in our homes overnight, the lead leaches into the water and poisons us
via our morning tea, coffee or home made orange juice. This incredibly
soft, yet sturdy metal, was the answer to a municipal water systems' dreams
in areas where ground shifting due to the soil structure and reactions
with permafrost are a problem. By using lead lined pipes, the outer structure
of the pipe could crack and split, but the soil would still keep the outer
structure around the lead liner for protection, but the lead liner could
withstand significant motion in the earth without rupturing. Great theory,
only it is now poisoning us.
How does one make concrete retain its strength yet develop some flexible qualities. Add asbestos Again years later, we have established that the body cannot rid itself of asbestos fibres. Finally the water from asbestos concrete distribution systems began to be sampled. The government set some basic guidelines, but they were sufficiently broad to ensure that no local municipality was going to go broke due to having to rip out miles of underground piping and replace it. The guidelines also ensured that municipal suppliers could not be sued successfully because the water they were supplying fell within the "guidelines". Cities like Winnipeg Canada have hundreds and hundreds of miles of this piping which can produce contaminant levels of 12 million fibres per litre/quart.
Nature's hydrological cycle has been overtaxed by toxic and domestic
dump sites, industrial and domestic wastes, pesticides, insecticides, herbicides,
fertilizers, PCBs, airborne pollutants and on and on. Nature's endless
cycle will continue to distribute the horrid creations of man, only we
can limit the amounts. It has become a factor we must deal with and educate
our children about. It cannot be ignored.
We have applied the term "chemicals" to a host of toxic inorganic and organic contaminants. This is an incorrect term but has become so common that it forms the correct "mental" picture that we wish to portray. A chemical is not necessarily "toxic" just because it is a chemical, and conversely just because a substance can be found naturally in nature does not mean that it isn't toxic. So lets have a quick look at some of these "toxic compounds".
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