lovesouthernsocial.com

Cyanide anion is extremely toxic and can cause many damages to health and the environment

Dan Dennis image in Unsplash

Cyanides are a family of chemical compounds that contain the highly reactive cyanide anion in their composition. Cyanide compounds commonly found in the environment are hydrogen cyanide and two of its salts, sodium cyanide and potassium cyanide. Hydrogen cyanide (HCN) is a colorless liquid or gas with a strong characteristic odor, while sodium cyanide (NaCN) and potassium cyanide (KCN) are water-soluble solids.

Cyanide can be found naturally in low concentrations in soil, water and vegetables such as wild cassava. Cyanides are used in electroplating, gold and silver extraction, metal cleaning, in the production of synthetic fibers, dyes, pigments and nylon, as a reagent in analytical chemistry, a fumigation agent and coal gasification. The main sources of anthropogenic cyanide emissions, in turn, are mining, chemical and metal processing industries and vehicle exhaust.

Gold Cyanidation

The cyanide leaching process of gold is known to have major impacts on the environment and human health. Gold cyanidation, the name given to this process, is used to extract gold from a raw ore taken from the ground. Cyanide dissolves the gold within the rock, removing it in liquid form. This gold is then treated to remove the cyanide to which it has been exposed.

Cyanidation of gold, however, is considered a threat to the environment and human health due to the high toxicity of cyanide. Furthermore, the surrounding lands, rivers and lakes can remain barren indefinitely.

With sustainability in mind, mining companies started to transform cyanide into a less toxic and more sustainable form before disposing of it. To minimize the impacts of disposal, companies have also started to line their disposal sites with a waterproof lining. Thus, they claim that this is an acceptable risk, but that there are still many harmful leaks around the mines.

Gold and its applications

There is no way to think about riches without thinking about gold. This bright, yellow, malleable and dense transition metal is present in everyday life in the form of jewelry, computer board components and many other products. It is normally found in its pure state in the form of nuggets, but it also exists in some minerals such as quartz and metamorphic rocks. Furthermore, gold can be found throughout the earth's crust and ocean waters, in lower concentrations.

Because it is soft, gold is usually hardened, forming a metallic alloy with silver and copper. Due to its good electrical conductivity and corrosion resistance, gold has many industrial applications.

Human exposure and health effects

Human exposure to cyanide occurs mainly through food ingestion and, to a lesser extent, through water. Certain foods, such as apple and almond seeds, contain moderate concentrations of cyanide. Others, such as wild manioc, have high concentrations and are dangerous when not prepared properly. Inhaling cigarette smoke and fires in buildings and homes is an important source of cyanide exposure for the general population.

The compound is also released during the pyrolysis of nitrogen-containing materials such as polymers (melamine, nylon and polyacrylonitrile) and natural materials such as silk and wool. In mining, the cyanide used in the leaching of gold is known to cause various damages to health and the environment.

Regardless of its origin, cyanide anion is extremely toxic to organisms, as it binds to the metallic groups of a series of enzymes, inhibiting its activity. The most important direct consequence is the blocking of the respiratory chain and the inhibition of oxygen metabolism.

The effects of acute cyanide exposure are seen in the central nervous and cardiovascular systems. The most common signs and symptoms are headache, dizziness, decreased motor coordination, arrhythmia, bradycardia, drowsiness, coma and death. The effects of chronic exposure are headache, difficulty speaking, gastrointestinal disturbances, muscle weakness, confusion, loss of visual acuity, and thyroid enlargement.

In addition to being used in suicides during World War II, it was also the base for the Zyklon B (Cyclone B) gas used in the extermination camps. In the United States, it served as a form of capital punishment in the gas chamber, but was abolished for causing a painful and slow death.

Cyanide leaching is prohibited

Thinking about the environment and their ways of life that Germany, Czech Republic, Hungary, Costa Rica, the states of Montana and Wisconsin in the United States and many regions of Argentina banned gold mining with cyanide. However, almost 90% of all world production is still made from the gold cyanidation process.