Copper
Copper is a
reddish metal with a face-centered cubic crystalline structure. It reflects
red and orange light and absorbs other frequencies in the visible spectrum,
due to its band structure, so it as a nice reddish colour.
It is malleable, ductile, and an extremely good conductor of both heat and
electricity. It is softer than iron but harder than zinc and
can be polished to a bright finish. It is found in group Ib
of the periodic table, together with silver and gold.
Copper has low chemical reactivity. In moist air it slowly forms a greenish
surface film called patina; this coating protects the metal from further
attack.
Applications
Most copper
is used for electrical equipment (60%); construction, such as roofing and
plumbing (20%); industrial machinery, such as heat
exchangers (15%) and alloys (5%). The main long established copper alloys are
bronze, brass (a copper-zinc alloy), copper-tin-zinc,
which was strong enough to make guns and cannons, and was known as gun metal,
copper and nickel, known as cupronickel, which was the preferred
metal for low-denomination coins.
Copper is ideal for electrical wiring because it is easily worked, can be
drawn into fine wire and has a high electrical conductivity.
Copper
in the environment
Copper is a
very common substance that occurs naturally in the environment and spreads
through the environment through natural phenomena. Humans widely use copper.
For instance it is applied in the industries and in agriculture. The production
of copper has lifted over the last decades and due to this copper quantities
in the environment have expanded.
The world's
copper production is still rising. This basically means that more and more
copper ends up in the environment. Rivers are depositing sludge on their
banks that is contaminated with copper, due to the disposal of
copper-containing wastewater. Copper enters the air, mainly through release
during the combustion of fossil fuels. Copper in air will remain there for an
eminent period of time, before it settles when it starts to rain. It will
than end up mainly in soils. As a result soils may also contain large
quantities of copper after copper from the air has settled.
Copper can be released into the environment by both natural sources and human
activities. Examples of natural sources are wind-blown dust, decaying
vegetation, forest fires and sea spray. A few examples of human activities
that contribute to copper release have already been named. Other examples are
mining, metal production, wood production and phosphate fertilizer
production.
Because copper is released both naturally and through human activity it is
very widespread in the environment. Copper is often found near mines,
industrial settings, landfills and waste disposals.
Most copper
compounds will settle and be bound to either water sediment or soil
particles. Soluble copper compounds form the largest threat to human health.
Usually water-soluble copper compounds occur in the environment after release
through application in agriculture.
World
production of copper amounts to 12 million tonnes a
year and exploitable reserves are around 300 million tonnes,
which are expected to last for only another 25 years. About 2 million tonnes a year are reclaimed by recycling. Today copper is
mined as major deposits in
Health effects of copper
Routes of exposition
Copper can be found in many kinds of food,
in drinking water and in air. Because of that we absorb eminent quantities
of copper each day by eating, drinking and breathing. The absorption of
copper is necessary, because copper is a trace element that is essential
for human health. Although humans can handle proportionally large
concentrations of copper, too much copper can still cause eminent health
problems.
Copper
concentrations in air are usually quite low, so that exposure to copper
through breathing is negligible. But people that live near smelters that
process copper ore into metal do experience this kind of exposure.
People
that live in houses that still have copper plumbing are exposed to higher
levels of copper than most people, because copper is released into their
drinking water through corrosion of pipes.
Occupational
exposure to copper often occurs. In the work place environment copper
contagion can lead to a flu-like condition known as metal fever. This
condition will pass after two days and is caused by over sensitivity.
Effects
Long-term
exposure to copper can cause irritation of the nose, mouth and eyes and it
causes headaches, stomachaches, dizziness, vomiting and diarrhoea.
Intentionally high uptakes of copper may cause liver and kidney damage and
even death. Whether copper is carcinogenic has not been determined yet.
There are scientific articles that indicate a link between long-term
exposure to high concentrations of copper and a decline in intelligence
with young adolescents. Whether this should be of concern is a topic for
further investigation.
Industrial exposure to
copper fumes, dusts, or mists may result in metal
fume
fever with atrophic changes in nasal mucous membranes.
Chronic
copper
poisoning results in Wilson’s Disease, characterized by a hepatic
cirrhosis,
brain damage, demyelination, renal disease, and
copper
deposition in the cornea.
Environmental effects of copper
When copper ends up in soil it strongly attaches to organic matter and minerals. As a result it does not travel very far after release and it hardly ever enters groundwater. In surface water copper can travel great distances, either suspended on sludge particles or as free ions.
Copper
does not break down in the environment and because of that it can
accumulate in plants and animals when it is found in soils. On copper-rich
soils only a limited number of plants has a chance
of survival. That is why there is not much plant diversity near
copper-disposing factories. Due to the effects upon plants copper is a
serious threat to the productions of farmlands. Copper can seriously
influence the proceedings of certain farmlands, depending upon the acidity
of the soil and the presence of organic matter. Despite of this,
copper-containing manures are still applied.
Copper
can interrupt the activity in soils, as it negatively influences the
activity of microrganisms and earthworms. The
decomposition of organic matter may seriously slow down because of this.
When the soils of farmland are polluted with copper, animals will absorb concentrations that are damaging to their health. Mainly sheep suffer a great deal from copper poisoning, because the effects of copper are manifesting at fairly low concentrations.