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Dissolved Iron |
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Sources |
Concerns |
Iron is naturally found in the earth’s crust, and dissolved iron
found in groundwater that is not exposed to oxygen. Water with
ferrous iron is clear and colorless until oxygen is absorbed and
reacts with the iron to form non-soluble ferric oxide (iron oxide
or “red rust”). The iron in homes may b
e from the incoming water
supply, or corrosion of steel piping components.
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Based on the EPA, the secondary regulation
limit for iron in drinking water is 0.3 mg/L. This number is strictly based
on aesthetics (odor and taste) as iron is not considered a health risk. Iron
is essential for good health because it helps blood to transport oxygen around
the body. The reasoning for the limit on iron is that it stains and contaminates
anything it touches leaving a gray, black, red-brown , or yellow-brown stain, and
has an unpleasing odor and taste in drinking water. Iron may also promote the
growth of iron bacteria (non-disease producing). They grow and multiply in water,
then oxidize the iron to insoluble ferric state to make a thick rust colored slime
or sludge on fittings or hoses. Organic iron combines with organic matter (tannins)
to stain water. This form is usually found in shallow wells and surface water.
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Remedies |
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Treatment of iron can include: aeration, filtration, adding chlorine bleach,
hydrogen peroxide or ozone, flushing, or cleaning by soaking iron stains in
sodium metabisulfite (iron out or rust out). |
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Manganese |
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Sources |
Concerns |
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Manganese is a gray-white metal resembling iron. It is hard,
very brittle, and has strong magnetic properties when in an
external magnetic field. Naturally manganese is rarely found
alone in water; it is usually dissolved along with iron.
Manganese is important as an industrial alloy used as pigment.
It also comes from natural deposits or deposited from airborne
sources. Manganese was used in the “Wartime” nickel from 1942-1945,
and in dollar coins minted since 2000.
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The U. S. Environmental Protection Agency recommends a limit of
0.05 mg/L (or parts per million) for aesthetics such as taste,
discoloration, and staining of laundry and plumbing. Manganese
deposits in plumbing cause black sediment and blackish turbidity.
Also, manganese bacteria are often present which can cause clogs
in piping. Manganese is an essential trace element needed by our
bodies (found in grains and teas).
Remedies are the same as iron above. |
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Hardness |
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Sources |
Concerns |
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Hard water is high in dissolved minerals, specifically calcium
and magnesium. The higher the amount of minerals, the higher the
hardness of the water.
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Hardness is not a health risk, it actually contributes a small
amount to the total calcium and manganese daily human requirements.
It does however cause mineral build-up on fixtures, poor soap and
detergent performance. Scale build-up of calcium and manganese
may
cause clogs in piping, and has been known to increase energy bills by
up to 25%.
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Remedies |
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Some tips to combat hardness are to choose soaps and detergents to
match the hardness of your water; reduce the temperature of your
boiler to ~55°C to reduce mineral deposits; and use white vinegar
or rinse agents in your dishwasher to remove the film from dishes.
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Dissolved Sulfate |
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Sources |
Concerns |
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Sulfates (SO4) are salts of sulfuric acid (H2SO4). They occur
naturally in rain water, or man-made from industrial waste,
battery acid, Epsom salts, plaster, some drugs, and algaecides.
Many of the sulfate salts are highly soluble in water. Sulfates
occur as microscopic particles from fossil fuel burning and can
create acid rain. There are two types of bacteria associated with
sulfate: sulfate reducing and sulfate oxidizing. Sulfate reducing
bacteria live where there is little or no oxygen (such as deep wells,
plumbing systems, water softeners, and water heaters), and they convert
sulfate and other sulfur compounds to hydrogen sulfide gas (gives off a
rotten egg smell). They are usually found in the hot water plumbing.
Sulfur oxidizing bacteria convert sulfide to sulfate, making a dark slime
that clogs piping, stains clothes, and blackens water (these are less
common than the reducing bacteria).
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The Environmental Protection Agency set a secondary drinking water regulation
maximum limit for sulfate at 250 mg/L (parts per million). This is because
dissolved sulfate has a bitter or medicinal taste, it corrodes copper piping,
it can cause extreme hardness, a scale can build up on piping, and it can have
a laxative effect (30 grains per gallon or more are consumed when combined with
calcium and magnesium).
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Remedies |
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Treatment depends upon the form and quantities of sulfate, the amount of
iron, manganese, and bacteria, and how much water must be treated. For a
small amount of water, distillation and reverse osmosis; and ion exchange
for large quantities. The last option is to find an alternative water source
such as bottled water, or tapping into the city water system.
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