Cadmium is a chemical element of the periodic table which is represented by the symbol Cd and whose atomic number is 48. It is in group 12 and is a white metal with a slight bluish tint, it has a lot of weight, is rare in abundance and It is among the metals with the highest level of toxicity among those that exist. It is closely related to zinc, and it is with it that it is found in nature, but it is more malleable and softer.
It is a metal that has a lot of ductility and its ion is colorless. Its atomic weight is 112.40, it has a density of 8.65 at 20 degrees Celsius. Its boiling and melting points are 765 degrees Celsius and 320 degrees Celsius respectively, both lower than those of zinc. A total of eight stable isotopes exist in nature and eleven have been described as artificially unstable radioisotopes.
Uses of Cadmium
- It is used in nickel-cadmium batteries.
- Previously, cadmium was used commercially to protect steel and iron from deterioration.
- It is used as a chemical reagent and pigment.
- Because it is very capable of absorbing neutrons, it is used in control rods to coat nuclear reactors.
- Its cadmium compounds are used to stabilize plastics.
Cadmium belongs to group IIb, in which mercury and zinc are also found. It is a divalent element in each of its stable compounds.
It does not occur freely in nature and its sulphide, which is its only ore, is not a commercial source of the metal. A large majority of it is obtained after the smelting and refining of zinc ores. Among the main source countries of this element are:
- United States
The Electron configuration of cadmium is: Kr 4d¹⁰5s²
Health Effects of Cadmium Use
This element is found mainly in the earth’s crust, almost always in combination with zinc. After its application, it reaches the environment through the soil, since it is found in pesticides and manure.
It reaches humans mainly through food, and foods that contain high concentrations of this element are capable of producing an increase in humans, such as shellfish, cocoa and mushrooms.
If a person is exposed to excessive concentrations of cadmium, the consequences can be very serious. One of the forms is given by smoking tobacco. The smoke is responsible for transporting the element to the lungs, then the blood carries it to the rest of the body and thus increases the effects of the cadmium already present in the body due to the consumption of foods that contain it in large quantities. .
People who live near landfills that dump highly hazardous waste or factories that release this element into the air, as well as those who work in metal refineries, are also at risk. Inhaling cadmium can cause severe lung damage and even death.
In addition, it can cause: bone fractures, damage to the nervous and immune systems, reproductive disorders and possible infertility, diarrhea, severe vomiting and stomach pain, it can damage DNA and increase the development of cancer.
Effects of using cadmium in the environment
More than 25,000 tons of this metal are released into the environment every year. Part in the rivers by the decomposition of rocks and in the air arrives by the fires of the Balkans and those that occur in the forests. The other half is released by certain human activities such as manufacturing.
Currently, thanks to the regulations, only a small quantity of cadmium reaches the water, this via the discharge of waste water towards industries or homes.
Cadmium discharged by industries in wastewater ends up in the ground. Cadmium is also emitted from fertilizer production, as it ends up in the soil when used on farms. Some of it reaches surface waters through what remains of the fertilizers used and dumped by companies.
Upon reaching the ground, invertebrate animals such as earthworms and other essential earth animal species are very susceptible to poisoning by this metal, they usually die even when exposed to very low concentrations, which can have important consequences on the structure of the plants. .earth.