Is gold biodegradable? (11 properties of gold)

This article shall answer the question of the biodegradability of gold.

This article shall also address other topics such as:

  • The properties of gold.
  • The applications of gold.
  • The biodegradation process.
  • The toxicity and eco-friendliness of gold.

Is gold biodegradable?

No, gold is not biodegradable. This is because the enzymatic makeup of the agents of biodegradation such as the bacteria and the fungi can not break down gold.

The biodegradation process occurs to naturally occurring, organic matter that is mostly derived from plants and animals.

The bacterial and fungal enzymatic machinery is capable of breaking down these organic molecules into simpler molecules.

What is biodegradation?

Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi into the water, carbon dioxide, methane, and minerals. Heat energy is produced in the process.

Biodegradation occurs in three distinct stages: biodeterioration, bio-fragmentation, and assimilation.

Biodeterioration is the first stage of biodegradation that involves abiotic factors such as light, UV radiation, and water to help in the weakening of the structure of organic substances.

Bio-fragmentation is the second stage that involves the physical breakdown of organic matter into small particles, this is due to the biodeterioration of the organic matter in the first stage.

Assimilation is the last stage of biodegradation. It involves the bacteria and the fungi taking up the minerals and small biomass produced by the previous two stages into their biological systems.

The minerals are used as a source of energy and carbon for the synthesis of cells and tissues.

Biodegradation can occur in the presence or absence of oxygen. When biodegradation involves the microorganisms using oxygen, the process is called aerobic biodegradation.

Aerobic biodegradation produces carbon dioxide, water, and small biomass. Heat energy is also produced in the process. Aerobic biodegradation occurs very fast but it is not very efficient.

When biodegradation occurs in the absence of oxygen, it is called anaerobic biodegradation. The products of anaerobic biodegradation include water, carbon dioxide, and small biomass. In addition to these products, methane gas is also produced. Heat energy is released during the breakdown. 

Anaerobic biodegradation occurs slowly but is more efficient than aerobic biodegradation.

Biodegradation can be affected by several factors such as water, light, temperatures, the bioavailability of a molecule, and pH.

Water helps in the biodeterioration and mechanical fragmentation of substances, increasing the surface area for microbial degradation.

Light emits radiations that help in the biodeterioration and bio-fragmentation of organic matter. UV radiation is the most effective radiation. 

Temperature affects the rate of biodegradation. Some microorganisms are very active in high temperatures while others are active in low temperatures. The optimum temperatures for the microorganisms increase the rate of biodegradation.

Bioavailability is the availability of an organic substance to microorganisms. Highly concentrated organic matter has high bioavailability and this increases the rate of biodegradation.

pH is the measure of acidity or basicity of a substance. Some microorganisms are very active in acidic pH while others are active in neutral or alkaline pH. Optimum pH increases the rate of biodegradation.

What is gold?

Gold is a chemical element that is naturally occurring in nature. It is chemically called Aurum, with a chemical symbol of Au and an atomic weight of 79.

Gold can be found naturally as a free element in the form of grains, it can also be found in the compound form together with silver, in a form called electrum.

Gold can also be found as an alloy with other metals such as copper, and palladium, and as a molecule within pyrite. And sometimes it occurs in compounds containing gold such as gold tellurides, a compound of gold and tellurium.

Gold is a transition metal in group 11 elements. It is usually found in rocks, veins, and alluvial deposits.

What are the properties of gold?

Gold is one of the heavy minerals that occur naturally. It contains several properties, some of which are used to determine its quality in the market.

The properties of gold include the following:

  • It is a naturally occurring metal element.
  • It is a bright metal, with a slight yellow color.
  • Gold in its pure form is very dense.
  • Gold is soft, ductile, and malleable and can therefore be hammered into sheets or made into wires.
  • Gold occurs in its pure form, or as an alloy of metals such as pallidum or copper.
  • Gold does not react with most chemicals.
  • It has resistance to most acids, except aqua regia ( a mixture of nitric and hydrochloric acids), which reacts with gold to form tetrachloroaurate anion.
  • Unlike silver, gold is insoluble in nitric acid, a property used to test the presence of gold in metallic compounds in a process called gold’s acid test.

The property is also used to refine gold.

  • Gold is soluble in an alkaline solution of cyanide, a property used in mining and electroplating.
  • Gold dissolves in mercury to form an amalgam.
  • Gold is a good conductor of both heat and electricity.
  • Gold is both mono nuclide ( found naturally as a single nuclide form) and monoisotopic ( occurring in one stable isotope).

What are the applications of gold?

Gold is considered the most valuable element on earth. It is popularly used as the standard through which the value of substances is measured.

The following are the uses of gold:

Monetary uses.

Gold was used as money for over a long time. It was usually exchanged with goods and services in the form of barter trade.

Gold mints and bars of various weights and quality were used as the standards of value. Gold had been standardized just like paper money today, for instance, a car could go for 1 kg gold, a piece of land for 1.5 kg gold, and such.

The elimination of gold and the introduction of paper money came about after World War II. 

Making of jewelry.

Gold is usually used to make jewelry and other related products. It is usually mixed with other metals to make alloys, which are used for the aforementioned purpose.

Gold is usually mixed with other metals to make alloys because pure gold is very soft. It also changes its ductility and hardness.

Most used alloys are pallidum-gold, copper-gold, silver-gold, and nickel-gold. Palladium-gold is the most expensive alloy.

Making electronics.

Gold is used in industry to make corrosion-resistant electrical connectors in devices such as computers.

Gold is used in electronic components because of its good conductivity of electricity, resistance to corrosion, highly ductile, and lack of toxicity.

In medical use

Gold compounds are generally used in the medical field for various reasons. 

Gold was usually used as an anxiolytic; for the treatment of the disorders of the nervous system.

Other ailments such as migraines, epilepsy, depression, amenorrhea, and impotence were treated using gold.

Gold is an inert element, as mentioned earlier, and because of this, the use of pure gold in medicine is something of contention. Effective gold compounds such as gold salts and radioisotopes are more effective in medical uses.

Sodium aurothiomalate and sodium auranofin are gold salts used to treat rheumatoid arthritis and tuberculosis because of their high anti-inflammatory properties.

Gold alloys are used in dentistry to fill tooth gaps or to coat teeth. 

In the food industry.

Gold can be used as a food additive, although this has raised concerns due to the possible presence of gold nanoparticles which can affect the genes of animals.

It is used as a decorative agent in the making of sweets and drinks.

Is gold toxic?

Pure gold is inert and therefore does not react with any compound in the body and as a result, it is non-toxic.

However, the alloys and salts of gold can be very toxic to animals and plants. Gold cyanides and cyanide chlorides are highly toxic to the liver and kidneys.

Gold toxicity can be treated using a chelating agent such as dimercaprol.

Is gold eco-friendly?

Yes, gold is eco-friendly since it does not react with anything in the environment due to its inert form.

The mining of gold has very negative impacts on the environment. Lands have been left derelict due to gold mining.

The potholes left after gold mining become the breeding ground for mosquitoes, therefore causing malaria.

Some holes dug during mining are so deep that in some parts of the world such as Kenya and South Africa, people have been reported dead after mining holes and caves crumbled on them.

According to a study, gold mining should be eco-friendly and sustainable if no toxic chemicals are used during the mining process.


This article has answered the question of the biodegradability of gold.

It has, in addition, covered other areas such as:

  • The properties of gold.
  • The uses of gold.
  • The toxicity and eco-friendliness of gold.

For any questions or comments please use the comment section below.

Frequently Asked Questions (FAQs): is gold biodegradable?

Is mining of gold ethical?

Yes, in some countries and industries, people mining gold has been treated with respect, but in some nations, there has been reported cruelty to people in gold mines. People going without pay, people working in deplorable conditions, and without proper PPEs are some of the major concerns.

What are the dangers of gold?

Gold mining leads to displacement of people and wildlife, land pollution and dereliction, death of gold miners, and contamination of water.

Can gold be recycled?

Yes, gold can be recycled many times without it losing its value, and therefore, gold is a very sustainable mineral.


Patrick Schein. Is recycled gold an ethical choice?

Retrieved from:

Adam Hayes. (March 09, 2022). Why Gold Matters: Everything You Need To Know. Reviewed by Michael J Boyle.

Retrieved from:

Schmidbaur, Hubert; Cronje, Stephanie; Djordjevic, Bratislav; Schuster, Oliver (2005). “Understanding gold chemistry through relativity”. Chemical Physics. 311 (1–2): 151–161


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