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Iron oxide and Hematite
constituting about 5% of the earth's crust.
may contain between 10% and 12% free silica. Iron compounds have
many applications , and iron oxide pigments are used in coatings
and as colorants in ceramics, glass, plastics, rubber and the
like.
Exposure :
average concentration of iron in soil is very high, 5000
mg/kg.
of the world, the atmospheric concentration is less than 1
ng/m³.Higher values are found in urban areas and close to
iron- and steel-producing plants.
with the proportions of iron-rich and iron-poor items that
comprise the diet, but in most industrial countries, it typically
ranges from 9 to 35 mg/day.
:
part in oxygen transport and utilization. Absorption of iron from
the gastrointestinal tract is adjusted to a fine homeostasis.
Under normal conditions, about 5% to 15% of iron in food is
absorbed, but the uptake increases considerably in the case of
iron deficiency or depleted iron stores. Normally, the human body
contains about 3 to 5 g of iron. Two thirds of this amount is
bound to hemoglobin in the blood.
stored in storage proteins (ferritin and hemosiderin) Elimination
is slow and takes place mainly via bleeding and by desquamation of
mucosal cells
deposition of iron in various organs may lead to secondary lesions
in these organs. In other diseases, iron deposition is a sequella
of pathologic processes.
characterized by increased absorption of iron which ends up after
the age of fifty in cutaneous pigmentation, liver cirrhosis and
sometimes diabetes. Other organs may be affected:
:
which is an iron overload of tissues, from hemochromatosis which
comprises tissue lesions due to martial (iron)
accumulation.
hemolysis, sideroblastic anemias, excessive iron intake by
parenteral route or, in the case of sideroblastic anemia, by oral
route.
disease, a disease encountered in regions where drinking water is
very rich in iron salts.
repetitive hemorrhages as in mitral stenosis, in idiopathic
pulmonary hemosiderosis;
intravascular hemolysis, paroxysmal nocturnal hemoglobinuria;
cutanea tarda.
during mining, both underground or open-pit, in iron and steel
foundries, during arc-welding, in connection with various metal
processing activities; and in silver polishing (using fine iron
oxide as a polishing rouge).
Effects
those found in common iron tablets taken in the treatment or
prophylaxis of iron-deficiency anemia, are potentially very toxic.
In doses exceeding 0.5 mg of iron, toxic effects with vomiting,
ulceration of the gastro-intestinal mucosa, and intestinal
bleeding may occur. In severe cases, liver and kidney damage may
also develop.
of iron oxide fumes, can give rise to roentgenologic changes in
the lung due to deposition of inhaled iron particles. The retained
dust produces x-ray shadows that may be indistinguishable from
fibrotic pneumoconiosis. It has
been named siderosis, iron pneumoconiosis, hematite
pneumoconiosis, iron pigmentation of the lung, and "arc welder's
lung", reflecting the fact that
it has been seen in many occupational groups exposed to iron oxide
fumes, including silver polishers.
roentgenologic lung changes to be benign without having any
influence on the lung function or progressing to fibrosis.
silicosis among iron ore miners if the exposure to free silica is
severe enough to cause fibrotic changes and subsequent
deterioration of the pulmonary function.
:
cancer has been observed among hematite miners exposed to iron
oxide, presumably as a result of concomitant radon gas exposure,
there is no evidence that iron oxide alone is carcinogenic to man
or animals. In a large (10,403) cohort study of Minnesota iron ore
(hematite) miners, they did not show any increased mortality in
lung cancer. This study is of particular interest, for the radon
levels in Minnesota iron ores, in contrast to most of the other
iron ore mines examined, was low. In addition, smoking was
prohibited underground, and diesel fuel vehicles were not used. No
evidence was found in a study for an increased lung cancer risk in
a plant producing sulfuric acid from pyrite (FeS2) where workers
had been exposed to iron oxide dust at very high concentrations
(50 to 100 mg/m³).
to conclude that iron oxides are not carcinogenic.
:
Pondérée) = 5mg/m³
last edition.
Toxic Exposures, Sullivan & Krieger; last edition.
Industrial Materials, Lewis C., last edition.
Intoxications Professionnelles, Lauwerys R.R. last
edition.
Proctor & Hughes, 4th edition.
Related Information
Links
| Materials | Natural Red Iron Oxide |
|---|---|
| Materials | Iron Oxide Yellow |
| Materials | Iron Oxide Black |
| Materials | Iron Oxide Red |
| Materials | Iron Chromate |
| Typecodes |
Article by Edouard Bastarache
Edouard Bastarache is a well known doctor that has written many articles on the subject of toxicity of ceramic materials and books on technical aspects of ceramics. He writes in both English and French. |
By Edouard Bastarache
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