Alkalinity and pH
by
Dr. Mark Sircus
Perhaps now that I am living in Sanctuary surrounded by two rivers,
which envelop us on three sides, I will get back to my Waters of Life
book and finally finish it. Here we are reminded every day the importance
of water and what it's like to drink it as it comes out the top of
a mountain. We do have a village water system for our little valley of
perhaps 70 simple homes but it is for collection and no treatment is done.
There is something I found with our drinking water that makes an interesting
lesson about alkalinity and pH. I tested our water and to my dismay it
was slightly acid but putting only a pinch of sodium bicarbonate into
a half gallon moved it powerfully to the alkaline. There is some confusion
between alkalinity and pH. It seems that it is not enough to drink high
pH water. Alkalinity also needs to be high for the high pH water to have
a strong medical affect.
Alkalinity is important because it protects
or buffers against rapid pH changes.
Alkalinity and pH are related to each other in ways that are obvious,
and in other ways that are subtle. The idea that alkalinity is separate
from pH (which is by 'coincidence' called either acid or alkaline)
is a myth though pH and alkalinity are two different measurable
parameters of water. Even though the pH can be very high we find
that un-mineralized water has little ability to neutralize acid in the
stomach to initiate the production of bicarbonate in the bloodstream.
Alkalinity is a measure of the buffering capacity
of
water - its ability to resist sudden changes in pH.
pH is a measure of how acidic or basic water is.
Alkalinity is the water's capacity to resist changes in
pH that would make the water more acidic. This capacity is commonly
known as "buffering capacity." For example, if you add the same
weak acid solution to two vials of water - both with a pH of 7,
but one with no buffering power (e.g. zero alkalinity) and the other with
buffering power (e.g. an alkalinity of 50 mg/l) - the pH of the
zero alkalinity water will immediately drop while the pH of the buffered
water will change very little or not at all.
pH simply expresses the degree of hydrogen ion concentration.
Alkaline means that the pH is greater than 7. Alkalinity is the
true measure of acid-neutralizing capacity which includes the
bicarbonate (HCO3^-1), carbonate (CO3^-2) and hydroxide
(OH^-1) ions. It is measured in mg/l or ppm as CaCO3.
Alkalinity of natural water is determined by the soil and bedrock through
which it passes. The main sources for natural alkalinity are rocks which
contain carbonate, bicarbonate, and hydroxide compounds. Borates, silicates,
and phosphates also may contribute to alkalinity. Limestone is rich in
carbonates, so waters flowing through limestone regions or bedrock containing
carbonates generally have high alkalinity - hence good buffering
capacity. Conversely, areas rich in granites and some conglomerates and
sandstones may have low alkalinity and therefore poor buffering capacity.
A pH less than 6.5 may contribute to the corrosion
of
pipes and fixtures and certainly if acid water can do
this one can only wonder what it does to human innards.
The pH level of drinking water is a measure of how acidic or basic it
is - pH is related to the hydrogen ions in water and stands for
"potential of hydrogen." Alkalinity is a measure of the capacity
of water to neutralize acids. It measures the presence of carbon
dioxide, bicarbonate, carbonate, and hydroxide ions that are naturally
present in water. At normal drinking water pH levels, bicarbonate,
and carbonate are the main contributors to alkalinity. As we can see in
the below graph the higher the CO2 the more alkaline the water at a given
pH.
In the chemistry of natural waters, there are several types of alkalinity
that are encountered. Each of these is a measure of how much acid (H+)
is required to lower the pH to a specific level. The reason that aquarists
measure alkalinity is that in normal seawater, most alkalinity
consists of bicarbonate and carbonate. Consequently, alkalinity
is an indication of whether or not adequate bicarbonate is present in
the water. Sodium bicarbonate is the main alkaline buffer in our blood.
Alkaline supplied from outside the body,
like drinking alkaline water, results
in a net gain of alkalinity in our body.
The main chemical species that contribute to alkalinity in seawater
are bicarbonate and carbonate. The table below (from "Chemical Oceanography"
by Frank Millero; 1996) shows the contribution to alkalinity from the
major contributors in seawater at pH 8.
|
Chemical Species
|
Relative Contribution To Alkalinity
|
|
HCO3- (bicarbonate)
|
89.8
|
|
CO3- (carbonate)
|
6.7
|
|
B(OH)4-(borate)
|
2.9
|
|
SiO(OH)3- (silicate)
|
0.2
|
|
MgOH+ (magnesium monohydroxylate)
|
0.1
|
|
OH-(hydroxide)
|
0.1
|
|
HPO4-and PO4-(phosphate)
|
0.1
|
Carbon dioxide has a specific solubility in water as carbonic acid (H2CO3).
At any given pH there is an exact mathematical relationship between
H2CO3 and both bicarbonate and carbonate. For example, at a pH
of about 9.3 in freshwater (about 8.4 in seawater) the carbonate concentration
is 100 times that of the carbonic acid. At higher pH this multiplier rises,
and there is consequently more bicarbonate and carbonate present.
Alkalinity rises sharply as pH is raised. This becomes
especially true above pH 8 in salt water, where there
becomes an appreciable concentration of carbonate.
The theoretical relationship between carbonate alkalinity
and pH for seawater (blue) and
freshwater (red) equilibrated with the atmosphere (350 ppm carbon dioxide).
Normal to high alkalinity implies adequate bicarbonate, while low alkalinity
implies that it is in short supply. Bicarbonated water is the healthiest
water to drink and that is made clear in my Sodium Bicarbonate book. It
is critical to see that alkalinity does not depend strictly on pH though.
There is a relationship between the two but pH measures the degree
of alkalinity but not its quantity. It is like the relationship
between temperature and heat. You can have a paper clip heated to 10,000
degrees but it will not heat a house nearly as well as 90-degree air blown
from a home heater.
Alkalinity measures the concentrations of bicarbonate,
carbonate, and hydroxide ions and is expressed as an
equivalent concentration of calcium carbonate (CaCO3).
Alkaline ionizers do not always deliver water that is sufficiently acid-neutralizing
to make a difference. Alkaline ionizer promoters equate acid-neutralizing
ability with high pH. From the discussion above we can see that it is
the parameter of alkalinity that neutralizes acid, not pH levels alone.
In other words you can have high pH and little alkalinity and you can
have low pH and a lot of alkalinity (e.g. sparkling mineral water). If
there is only a small amount of alkaline elements (from the first two
columns of the Periodic Chart) an ionizer will generate a meager quantity
of acid neutralizing alkalinity - but the pH will still show as
a high alkaline value (e.g. 8.5 to 10.5).
The presence of calcium carbonate or other
compounds such as magnesium carbonate
contribute carbonate ions to the buffering system.
People living in low mineral areas (many city supplies and wells) think
they are getting a good dose of alkalinity from their ionizers when they
would be much better off with 1/2 tsp. of baking soda or a shot glass
of Gerolsteiner Sparkling Water. So it will be advised for many users
of water ionizers to add sodium bicarbonate to their water if they are
looking for stronger healing effects.
"Alkaline water" is not the same as "water
with alkalinity". For this
reason, water with a pH of 6.3 (e.g., sparkling mineral water) can
have hundreds of times more acid-neutralizing "alkalinity"
than water with an alkaline pH of 9.5 from an alkaline-ionizer.
Robert Slovak
The shortcoming of ionizers is simply that the input water chemistry
determines its degree of benefit in terms of acid-neutralizing alkalinity
(not pH!) and negative ORP (active hydrogen). The quality of one's
"raw" water resource has to have a lot to do with our decision
in terms of filters and ionizers chosen.
Water Ionizers
Most practitioners promote the idea that alkaline pH implies significant
acid-neutralizing capacity - but that is not always correct. There
are good reasons to suggest that those who have ionizer machines should
add extra alkalinity (bicarbonate) - if the mineral content of their
water supply is low. When the source water is low in minerals (most public
drinking waters are low in minerals especially magnesium and bicarbonate)
re-mineralization becomes critical.
Conclusions
Alkaline solutions, at about pH 8.5 has been shown
to overtly
increase the antioxidant effect by up to 60% relative
to the same compound tested in a near biological pH of 7.4.
Sang Whang, one of the world's great experts on reversing aging
reminds us that, "The ingredients in the stomach cell that make hydrochloric
acid (HCl) are carbon dioxide (CO2), water (H2O), and sodium chloride
(NaCl) or potassium chloride (KCl)."
NaCl + H2O + CO2 = HCl + NaHCO3, or
KCl + H2O + CO2 = HCl + KHCO3
Wang says, "In order to digest food and kill the kinds of bacteria
and viruses that come with the food, the inside of our stomach is acidic.
The stomach pH value is maintained at around 4. When we eat food and drink
water, especially alkaline water, the pH value inside the stomach goes
up. When this happens, there is a feedback mechanism in our stomach to
detect this and commands the stomach wall to secrete more hydrochloric
acid into the stomach to bring the pH value back to 4. So the stomach
becomes acidic again. When we drink more alkaline water, more hydrochloric
acid is secreted to maintain the stomach pH value."
As we can see from the above chemical equations the byproduct of making
hydrochloric acid is sodium bicarbonate (NaHCO3) or potassium bicarbonate
(KHCO3). In response to ingestion of sodium bicarbonate or high
pH alkaline water the production of hydrochloric acid is actually increased
because the stomach responds to lower the pH back down to normal acidic
conditions. So as we take more alkalinity from drinking high pH and alkaline
water, it forces our stomach to produce more acid (and a balancing amount
of bicarbonate). The bottom line is that a net gain of alkalinity is achieved
in the body and this is extremely helpful in a body struggling to maintain
equilibrium.
Reference
[1] Lee, H., Cha, M., Kim, I. Activation of thiol-dependant antioxidant
activity of human serum albumin by alkaline pH is due to the b-like conformational
change
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