by John Ashton and Ronald Laura
Following a workout in the gym, a training run or
cycle, a game of squash or a mountain hike, the thought of a refreshing
drink of cool, clear water is often uppermost in our minds. Adequately
quenching that thirst is a vital aspect of maintaining fitness, health
and even beauty.
But how pure is the water we drink and are the chemicals used to purify
it serving, paradoxically, to contaminate it? Unless we are fortunate
enough to live in an unpolluted rural environment collecting our own
water (or have a water filter or purchase purified water), the peculiar
odour and taste of the liquid in our glass serves as a persistent reminder
that the water we drink contains chemicals. Generally, the most noticeable
of these is chlorine.
We have come to accept the presence of chlorine in our drinking water
as one of the necessary, though slightly unpleasant, aspects of maintaining
community health. Most of us have learned that a number of contagious
diseases such as typhoid and cholera have been virtually eradicated
by filtering and chlorinating our municipal water supplies.
The crucial question which many of us never learned to ask, however,
is whether chlorinated water represents a health hazard in its own right.
In what follows we shall present some of the more neglected research
on the subject, with the aim of allowing the reader to make more informed
decisions about the merit of treating our drinking water with chlorine.
What is Chlorine and How Does it Work?
The Australian bicentennial year, 1988, marked the centenary of water
chlorination. In 1888, a patent on chlorination of water was granted
to Dr Albert R Leeds, Professor of Chemistry at Stevens Institute of
Technology, Hobokin, New jersey. Professor Leeds showed that chlorine
could be used to control pathogens responsible for waterborne diseases.
In the following year, the first chlorination of a public water supply
was initiated at Adrian, Michigan, though it was not until 1908 that
chlorination was introduced on a large scale for the water supply to
Jersey City, New Jersey. By World War II the practice of chlorination
was widely established in the US. (1)
Water chlorination involves a relatively straightforward chemical process.
Chlorine is one of the most reactive elements in nature and is found
in a free form only in volcanic gas. Even a small amount of chlorine
will dissolve in water, some combining with it to form hypochlorous
acid and hypochlorite ion. Chlorination is achieved by adding chlorine
gas directly to the water or by adding the chemicals, calcium hypochlorite
or sodium hypochlorite. In these latter forms, chlorine is known as
‘free available chlorine’ and has effective germicidal powers
because of its ability to combine with, or oxidise, classes of organic
compounds essential to life.
One theory as to how chlorine works is that there is a physio-chemical
reaction between chlorine and the structural proteins of the bacterial
microbes, thus causing the disintegration of their cell walls. Another
popular theory holds that the process of disinfection works by inhibiting
a key enzymatic process which oxidises the glucose of the cell. In other
words, the bacteria die because the chlorine destroys the oxidation
process upon which they depend.
Common practice is to apply chlorine both before and after filtration.
The pre- chlorination serves to reduce the ac*****ulation in filters of
biological material such as algae, while post-chlorination is intended
to minimise the number and variety of bacteria which would otherwise
enter the distribution system. Chlorine also combines with ammonia and
organic nitrogen compounds forming chloramine. When ammonia is combined
with chlorine, a slower acting disinfectant results, which has been
found to be beneficial in the suppression of iron-fixing or slime-forming
types of bacterial growths.
Chlorination is not employed as a substitute for other forms of water
treatment. On the contrary, the effectiveness of the process to some
extent depends upon other treatments such as filtration. Being a very
reactive element, chlorine will readily react with many other substances
which may be found in water. If some of these substances are present
in the water even in minimal quantities, they may create a chlorine
demand which significantly reduces the available chlorine for germicidal
purposes. Consequently, chlorination is often accompanied by filtration
to reduce the presence of such substances.
Chlorine is notorious for its pungent and disagreeable odour. The human
olfactory sense is capable of detecting chlorine at a level of only
a few parts per million in the atmosphere, and a concentration of only
50 to 60 parts per million (ppm) can cause serious illness in 30 to
60 minutes. Being a toxic substance, it is capable of causing major
congestion of lung tissue and even death, if breathed in sufficient
The odour and taste of chlorinated water may be produced by the presence
of excess chlorine or, strangely, it may also occur if insufficient
chlorine has been added. In the latter case, the characteristic odours
and taste occur when chlorine reacts with organic matter such as algae
in the water. When stronger chlorine levels are used, the organic matter
in the water is destroyed completely, and the result is water which
is virtually odour free. When the odour is minimal it would thus be
misleading to conclude that chlorine levels are low and vice versa.
The Potential Health Risks
From Chlorinated Water
It is amazing to think that a very reactive and poisonous chemical could
be deliberately added to public drinking water without an extensive
study of the possible harmful health effects being carried out beforehand.
Yet with chlorination, this appears to have been the case. In 1951,
Dr W J Llewellyn wrote to the editor of the Journal of the American
Medical Association: “What studies have been made to determine
the deleterious effects of the heavily chlorinated water used for drinking
purposes? The water supply in our town is chlorinated but not filtered.
At times it is possible to smell the chlorine. Could this harm the gastrointestinal
tract or the genitourinary tract?” (2) The editor replied:
“A search of the literature did not reveal any organised investigations
on the problem of the effect of heavily chlorinated water on the human
body. Allergic manifestations of chlorinated water have been reported.
Many cases of asthma have been traced to an allergy to chlorinated water.
In all these cases the asthma was relieved or disappeared when the patient
drank distilled or unchlorinated water.” (3) In the 1970s, popular
health writers such as Linda Clark (4) and Richard Passwater (5) warned
their readers that water chlorination may be a significant factor in
heart disease. In his 1984 book, titled Coronaries, Cholesterol, Chlorine,
Dr J M Price reported a study where, in contrast to the control group,
*****erels reared on highly chlorinated water all showed evidence of
either atherosclerosis of the aorta or obstruction of the circulatory
system. He wrote:
“The abdominal aortas (the place where atherosclerosis is known
to occur in chickens) of all the *****erels dying after four months were
carefully examined. In more than 95% of the experimental group, grossly
visible thick yellow plaques of atherosclerosis protruding into the
lumens were discovered!” (6) These chickens were noted to have
an extremely high, apparently spontaneous death rate and common findings...
were haemorrhage into the lungs and enlarged hearts... At seven months
there were so few experimental chickens remaining alive that the survivors
were sacrificed, with identical findings. At the same time one-third
of the apparently healthy control group was also sacrificed with not
one abnormal aorta found!”
Price goes on to describe how he repeated the experiment, this time
replacing the distilled water in the diet of half the remaining control
group with the heavily chlorinated water. Again, gross atheromas of
the aortas were found in the animals fed the chlorinated water.
Subsequent studies by N. W. Revis and co-workers from the Oak Ridge
Research Institute in Tennessee and the US Environment Protection Agency
added more weight to the insidious link between water chlorination and
heart disease. The researchers reported that they observed “hypercholesteraemia
[excess cholesterol in blood] and cardiac hypertrophy [enlarged heart]
in pigeons and rabbits exposed to chlorinated drinking water” and
“significant increases in plasma cholesterol and aortic atherosclerosis
in pigeons exposed to three commonly used drinking water disinfectants
[chlorine, chlorine dioxide and monochloraminel]” (7)
Water chlorination has also been linked to
an increased risk of cancer.
In Massachusetts, a case-control study of 614 individuals who died primarily
of bladder cancer and 1,074 who died of other causes, revealed a positive
association between bladder cancer incidence and chlorinated. drinking
water. (8) Another study involving 2,805 cases of bladder cancer and
5,258 controls from ten areas in the US revealed that the risk of bladder
cancer increased with intake level of beverages made with chlorinated
In Colorado, where water had been chlorinated for drinking purposes
for many years, University of Colorado researchers found that prolonged
exposure to chlorinated water significantly increased the risk for bladder
cancer. The risk was 80% higher in individuals using chlorinated water
for 30 years or more compared with those who had not used chlorinated
In 1993, J. K. Dunnick and R. L. Melnick from the National Institute
of Environmental Health Sciences in North Carolina assessed the carcinogenic
potential of chlorinated water. They found that the chlorination by-products,
trihalomethanes, were carcinogenic in the liver, kidney and intestine
of rodents. (11) Their results reinforced earlier animal studies which
linked water chlorination and cancer. (12)
A chlorinated organic compound is now believed to be one of the principal
agents responsible for the mutagenic activity of chlorinated tap-water.
(13) This powerful mutagen is produced as a result of the reaction of
chlorine with humic substances in the water and has the potential to
persist in significant quantities throughout the water distribution
system. (14 ) Water chlorination is now known to produce a range of
chlorinated organic compounds which are euphemistically termed ‘disinfection
by- products’. (15)
In 1992, R D Morris and co-workers from the Medical College of Wisconsin
in Milwaukee, carried out a major review of the studies on water chlorination
and cancer. Using an accurate meta-analysis technique to analyse the
data, they found a positive association between the consumption of chlorination
by-products in drinking water and bladder and rectal cancer in humans.
Recently, L. S. Pilotto from the National Centre for Epidemiology and
Population Health at the Australian National University in Canberra,
also reported that there are now several studies which suggest a clear
link between exposure to chlorinated drinking water and the development
of bladder cancer. (17)
Chlorination of Water and Nutrition
We have seen that chlorine is a very reactive chemical in water, but
what are its effects once this chemical enters our body, where it is
exposed to a complex and delicately balanced biochemical organism? Chlorine
is a powerful oxidising agent that readily destroys, oxidises or combines
with organic substances such as certain vitamins, enzymes, unsaturated
fatty acids and beneficial bacteria.
Let us first consider its impact upon ascorbic acid (vitamin C). Among
other important functions, this vitamin is associated with the body’s
protective action against pollutants. Vitamin C, however, is destroyed
by chlorine. At the same time, if vitamin C is present in sufficient
quantities, it can over time, reduce chlorine to harmless chloride ion,
provided the chlorine has not combined with some other organic compound
in the meantime. Thus fruit juices which contain vitamin C might plausibly
offer some protection against the chlorine contained in the water added
to reconstitute them.
Another important vitamin affected by chlorine is vitamin E. It is well
known that vitamin E is essential for maintaining the integrity of the
coronary and reproductive systems. Once again, chlorine destroys vitamin
E, so it may be that drinking large amounts of chlorinated water destroys
vitamin E in the body. If this hypothesis were true, it would help explain
the purported correlations between chlorinated water and heart disease
mentioned earlier. Excess saturated fats in the diet have been associated
with heart disease for some time now, and most people are aware of the
increasing emphasis to replace certain types of saturated fats in the
diet with unsaturated fats, coupled with a reduction in overall fat
intake. Chlorine reacts readily with unsaturated compounds, and whenever
chlorinated water and unsaturated fats are mixed, the resultant organochlorine
compounds are likely to have toxic properties. The chlorination of flour
produces chlorinated fatty acids and in animals fed these fatty acids
significant increases in heart weight have been observed. (18) The implications
of these increases for the human heart need to be seriously investigated.
Chlorinated Water And The Unknown Hazards of
There is another side to the chlorine-water story. When we return from
a gym workout or jogging session, not only are we thirsty, but we usually
shower or bathe to wash away perspiration. We have been taught that
cleanliness and health go together, and indeed they do, when chemical-free
water is used. When chlorinated water is used, however, bathing may
he much less healthy than we ever supposed.
Gases are, as a rule, less soluble in hot water, and when water is heated
or boiled dissolved gases are released. Boiling water is a way in which
the free chlorine content in water is greatly reduced, the chlorine
escaping into the air. When we have a hot shower or run a bath we can
sometimes smell the chlorine as it escapes from the hot water. In a
confined shower recess, however, especially one with poor ventilation,
as we continue our hot shower, the chlorine steadily increases in concentration
in the air we breathe. The olfactory threshold for chlorine is about
3.5 parts per million (ppm) so when we can smell chlorine the concentration
is already above this level. The lethal concentration for ten-minute
exposure is about 600 ppm.
We suggest that regularly taking long hot showers with chlorinated water
could pose a health risk. Chlorine causes pulmonary oedema, and it would
seem likely that regular exposure to chlorine gas even at low levels
such as in normal showering may reduce the oxygen transfer capacity
of the lungs. This could be a critical factor for athletes and for others
prone to heart failure.
Another aspect to be considered is our skin, which is an important protective
barrier for our bodies. When we shower with chlorinated water we are
exposing our skin to a relatively large volume of a dilute chlorine
solution. Some of this chlorine reacts with the oils in the skin to
form chlorinated compounds, and it is these compounds which may then
be absorbed by the body. Recent research has also shown that the concentration
of certain chlorination by-products known as trihalomethanes (THM) is
actually about 50% higher in hot water than in cold. The researchers
point out that the estimated lifetime cancer risk associated with exposure
to THM in water during showering is therefore underestimated by 50%
if the concentration in cold water is used to estimate the risk. (19)
It seems very likely, considering the strong oxidising power of chlorine,
that regular exposure to chlorinated water promotes the aging processes
of the skin, not unlike extended exposure to sunlight.
Moreover, chlorine may enhance the ageing effects of ultraviolet radiation
by reinforcing the process of cell deterioration. In particular, some
health researchers from the University of Nijmegan in The Netherlands
are now suggesting that water chlorination may he a significant factor
in melanoma risk. They point out that the skin pigmentary system appears
to be a target organ for chlorine compounds and chlorination by-products.
(20) The researchers have also found that people who regularly swim
in chlorinated swimming pools have more than twice the incidence of
melanoma compared with those who swim in unpolluted waters. (21) Another
skin factor to be considered is the destruction by chlorine of the natural
bacterial balance on the skin. The skin has an ecology all of its own,
which needs to be preserved in order to maintain healthy skin and its
No Cheap, Foolproof Solution
Despite the overwhelming evidence of the health dangers of water chlorination,
chlorine has remained the disinfectant of choice for most water authorities
because it is relatively cheap and is promoted as being highly effective.
It is argued that, while there are disadvantages associated with the
formation of the organochlorine byproducts, the risk due to the presence
of these impurities is far outweighed by the reduction in mortality
due to waterborne diseases. (22) The 1991 Peruvian cholera epidemic
is often cited as a case in point. Peruvian authorities abandoned the
practice of disinfecting water because of concerns about the health
risks. This led to a major cholera epidemic which spread to other countries
in South America and caused widespread illness and death. (23)
Let us make clear that we are not advocating that it is unnecessary
to ensure that drinking water is safe. What we are arguing is that water
chlorination is not as safe as we are often led to believe. In addition
to the subtle health effects discussed earlier, chlorination does not
necessarily destroy all viruses, parasites and harmful microorganisms
such as cryptosporidium and giardia. (24) Both these latter organisms,
which can be present in water supplies, can cause diarrhoea and a flu-
like intestinal illness. Both can survive normal chlorination, and this
fact was made apparent in the city of Milwaukee in the US in 1993. In
a massive disease outbreak, an estimated 400,000 cases of diarrhoea
occurred over a 14-day period in a single city. (25)
There is probably no cheap, foolproof water treatment, which shows the
need to consider the total community hygiene problem, particularly the
disposal of sewerage and other wastes in our environment.
We believe, however, that nature provides clues to the solution of this
controversial environmental problem. It is commonly known that sunlight
and oxygen disinfect water, and the efficiency of sunlight as a drinking
water sterilising agent has been promoted by A. Acra and others. (26)
Research has shown that sunlight can purify water that is highly contaminated
with faecal bacteria. (27) In another experiment, the organochlorine
solvent, trichloroethylene, which pollutes ground water in some parts
of the US, was reduced from a concentration of 1 to 2 parts per million
to less than 50 parts per billion with a five-minute exposure to concentrated
sunlight. (28) Ultraviolet light-based water treatments which add no
chemicals to the environment can be extremely effective. When correctly
used, UV treatment can kill all bacteria and all forms of viruses in
drinking water, although bacterial spores and some parasitic protozoa
can survive. (29)
The Educational Goal
The complete chlorine-health picture is even larger and more disconcerting
than we have intimated in the limited space available. Whenever a toxic
substance is added to the environment in large quantities, the overall
balance of nature is bound to he changed, and the chain of reactions
produced are likely to be very disruptive, far- reaching, and often
unexpected. One need only mention, for example, the detrimental impact
upon the ozone layer caused by water chlorination by-products such as
chloroform which may find their way to the upper atmosphere. (30)
With education we can begin to discern that nature carries within itself
an important pattern for the design of our health and optimum fitness,
and even for the natural beauty of ourselves and the planet. It is apparent
that nature did not intend that we despoil the planet and ourselves
by contaminating it with the waste products of the technology we have
used to dominate it. After 100 years of chlorination, it is surely time
to express our misgivings about the prospect of continuing until we
celebrate its bicentenary.
What You Can do
Since fluoride, chlorine and aluminium are routinely added to most of
our municipal water supplies, the problem of finding chemical-free drinking
water is difficult. When we appreciate the extent to which drinking
water has been degraded, it is evident that we need, as a community,
to join together to do something about it. If we cannot avoid the chemical
contamination of our water supplies, one of the first things we need
to do is to become sufficiently informed to lobby influential politicians
and to protect against, with the help of the media, the progressive
deterioration of our drinking water. In this regard it will probably
be necessary to find a spokesperson or spokespersons who can represent
accurately and authoritatively the nature of the problems and the options
available. In the meantime there are a few things we can do to minimise
the harmful effects of the toxic substances contained in water.
Water filters are probably the least expensive devices to improve the
quality of poor drinking water. Unfortunately, the claims made for water
filters by their manufacturers are often grossly exaggerated. A number
of filter systems are applauded for their ability to produce pure, crystal-clear
and safe water by removing all solids down to the most minute particles,
including residues of rust, minerals, toxic metals and organic contaminants.
The truth is that the most sophisticated large-scale filter systems
cannot deliver quite that much.
The best of household filters, however, can be used to reduce turbidity,
and to filter to some extent rust particles, dirt and suspended matter.
In addition, filters help to ensure cleaner-looking water and to minimise
a range of tastes and odours which would otherwise be regarded as objectionable.
The idea that tap-water filters eliminate harmful bacteria is somewhat
misleading. Because the activated charcoal in the filter effectively
absorbs chlorine, the reduction in chlorine levels allows certain bacteria
to propagate freely. In this regard, filtered water and the filter itself
may become a breeding ground for bacteria. The most efficient type of
filter seems to be made up of two different filter cartridges, one of
which depends upon granulated carbon as a filtering agent. This type
of filter has been reported to remove up to 93% of trihalomethanes,
a group of carcinogenic compounds, one of the best known of which is
Water purifiers can also help to improve water quality by reducing bacterial
levels. There are several different types of purifiers. One type utilises
ultraviolet light to kill bacteria, but its germicidal effectiveness
depends upon factors such as the intensity of ultraviolet light used,
coupled with its wave length. This type of purifier becomes less effective
when the water temperature drops below 10 degrees Celsius. Its effectiveness
is also reduced if the water is turbid or contains organic substances.
The presence of colours or iron may further decrease effectiveness,
as can the rate of flow of water passing through the system. Control
devices ordinarily restrict the water flow to about 36 litres per minute.
The use of minute amounts of silver ions, which are released as the
water passes through the filter, is another method of purification.
Because some of the silver escapes into the water which has been purified,
you may be imbibing some of the silver. Although there are allegedly
no toxic effects which silver is known to have on humans, we recommend
caution in the use of this type of purifier.
The reverse osmosis method involves the use of a semi-permeable membrane
to eliminate impurities. In addition to being susceptible to clogging,
the membrane permits the passage of certain contaminants such as iron
and nitrate. Because the membrane traps particles in the process of
preventing their passage, some organic chemicals may in fact become
The most basic method of water purification is boiling, which does serve
to kill virtually all bacteria. It will also remove many organic contaminants,
but it may serve to concentrate others. Boil when in doubt, but don’t
doubt that there are still impurities.
There is some evidence that a household distiller offers the most effective
means of purifying water. The water is heated to the point of vaporisation
and is then condensed. Although distilling eliminates many contaminants,
some carcinogens such as benzene may be carried over into the distillate.
Despite its benefits as a purifier, distilling may not be the best means
of purifying water for constant use. The reason is that it evacuates
the water of minerals and upsets the electrolyte balance of the water.
If you persist in drinking distilled water, you may find that the electrolyte
equilibrium of your body is disrupted by the deprivation of minerals
ordinarily contained in natural water. People who regularly drink distilled
water should at least supplement their diets with mineral tablets or
some natural mineral source such as dolomite. While supplementation
may have some benefits, it would he imprudent to assume that the body’s
electrolyte balance can easily be restored in this way.
Check the labels!
If you live in an area relatively free of air pollution and away from
crop spraying, it is possible to collect fresh drinking water during
heavy rains. Where it is difficult or impossible to do this, one option
is to buy bottled water. There are many types of bottled water commercially
available, but not all bottled water is worth buying. Imported brands
are expensive, especially if you are drinking the recommended eight
to ten glasses of water per day, each glass being approximately 250
ml. For a family of four or five, the cost quickly becomes prohibitive.
Mineral waters contain varying quantities of sodium and some brands
are sufficiently high in sodium that they can cause water retention
and bloating. They can also provide a problem for people who, for medical
reasons, are on low-sodium diets.
When purchasing bottled water, brands which use glass rather than plastic
containers are to be preferred, as glass does not generally transmit
odours or alter the taste of the water. It is also worth checking the
bottle cap before purchasing because seals can sometimes be faulty or
otherwise broken in transport or by tampering.
A final word of caution - the word ‘spring’ is often bandied
about in advertisements for bottled water, or appears on the label in
a variety of forms such as ‘spring clean’, ‘spring pure’
or ‘spring fresh’. Check to determine whether the water is
in fact ‘natural spring water’. The labels are not simply
interchangeable! Remember, when you purchase bottled water - especially
if you intend to become a regular customer - you have every right to
ask the manufacturer to provide an analysis of the contents of their
product. Sad to say, some bottled water has been found to have more
impurities than ordinary tap-water.
Copyright © by The Australian Vegetarian Society All Right Reserved.