Environmental Impact and Health Effects of Cadmium

Cadmium is a lustrous, silvery-white, ductile, verycadmium uptake by plants. This is a potential
malleable metal. Its surface has a bluish tinge anddanger to the animals that are dependent upon
the metal is soft enough to be cut with a knife,the plants for survival. Cadmium can accumulate in
but it tarnishes in air. It is soluble in acids but not intheir bodies, especially when they eat multiple
alkalis. It is similar in many respects to zinc but itplants. Cows may have large amounts of
forms more complex compounds. Aboutcadmium in their kidneys due to this. Earthworms
three-fourths of cadmium is used in Ni-Cdand other essential soil organisms are extremely
batteries, most of the remaining one-fourth issusceptive to cadmium poisoning. They can die at
used mainly for pigments, coatings and plating, andvery low concentrations and this has
as stabilizers for plastics. Cadmium has been usedconsequences for the soil structure. When
particularly to electroplate steel where a film ofcadmium concentrations in soils are high they can
cadmium only 0.05 mm thick will provide completeinfluence soil processes of microorganisms and
protection against the sea. Cadmium has thethreat the whole soil ecosystem. In aquatic
ability to absorb neutrons, so it is used as aecosystems cadmium can bio accumulate in
barrier to control nuclear fission.mussels, oysters, shrimps, lobsters and fish. The
Cadmium can mainly be found in the earth's crust.susceptibility to cadmium can vary greatly
It always occurs in combination with somebetween aquatic organisms. Salt-water organisms
offensive metals and consists in the industries asare known to be more resistant to cadmium
their inevitable by-products. After being applied itpoisoning than freshwater organisms. Animals
enters the environment mainly through theeating or drinking cadmium sometimes get high
ground, because it is found in manures andblood-pressures, liver disease and nerve or brain
pesticides. Naturally a very large amount ofdamage.
cadmium is released into the environment. AboutÂ
half of this cadmium is released into rivers throughHuman uptake of cadmium takes place mainly
weathering of rocks and some cadmium isthrough food. Foodstuffs that are rich in cadmium
released into air through forest fires andcan greatly increase the cadmium concentration in
volcanoes. The rest of the cadmium is releasedhuman bodies. Examples are liver, mushrooms,
through human activities, such as manufacturing.shellfish, mussels, cocoa powder and dried
No cadmium ore is mined for the metal, becauseseaweed. An exposure to significantly higher
more than enough is produced as a byproduct ofcadmium levels occurs when people smoke.
the smelting of zinc from its ore, sphalerite (ZnS),Tobacco smoke transports cadmium into the
in which CdS is a significant impurity, making up aslungs. Blood will transport it through the rest of
much as 3%. Consequently, the main mining areasthe body where it can increase effects by
are those associated with zinc. Âpotentiating cadmium that is already present from
Cadmium waste streams from the industriescadmium-rich food. Other high exposures can
mainly end up in soils. The causes of these wasteoccur with people who live near hazardous waste
streams are for instance zinc production,sites or factories that release cadmium into the
phosphate ore implication and bio industrial manure.air and people that work in the metal refinery
Cadmium waste streams may also enter the airindustry. When people breathe in cadmium it can
through (household) waste combustion and burningseverely damage the lungs. This may even cause
of fossil fuels. Because of regulations only littledeath.
cadmium now enters the water through disposalCadmium is first transported to the liver through
of wastewater from households or industries.the blood. There, it is bond to proteins to form
Another important source of cadmium emission iscomplexes that are transported to the kidneys.
the production of artificial phosphate fertilizers.Cadmium accumulates in kidneys, where it
Part of the cadmium ends up in the soil after thedamages filtering mechanisms. This causes the
fertilizer is applied on farmland and the rest of theexcretion of essential proteins and sugars from
cadmium ends up in surface waters when wastethe body and further kidney damage. It takes a
from fertilizer productions is dumped byvery long time before cadmium that has
production companies. Cadmium can beaccumulated in kidneys is excreted from a human
transported over great distances when it isbody. Other health effects that can be caused by
absorbed by sludge. This cadmium-rich sludge cancadmium are: diarrhoea, stomach pains and
pollute surface waters as well as soils.severe vomiting, bone fracture, reproductive
Cadmium is strongly adsorbed to organic matterfailure and possibly even infertility, damage to the
in soils. When cadmium is present in soils it can becentral nervous system, damage to the immune
extremely dangerous, as the uptake through foodsystem, psychological disorders, and - Possibly
will increase. Soils that are acidified enhance theDNA damage or cancer development.