What is a naturally-occurring chemical?

Last update 23 January 2017

Factors to consider

In determining whether a chemical meets the definition of a naturally-occurring chemical, a number of factors need to be considered, including:

  • how was the substance obtained,
  • has the substance been obtained after some form of processing,
  • if so, what type of processing,
  • was heat used in the processing, and
  • was there any likelihood of chemical change during processing.

Explanatory notes on the definition

a. Unprocessed chemicals occurring in a natural environment

Unprocessed chemicals can be obtained from plants, micro-organisms or animals without any processing at all—for example blood and milk from animals.

This also applies to inorganic matter such as minerals, ores, crude oil, coal and natural gas obtained from the earth or sea without any processing.

b. Chemicals extracted without a chemical change

This refers to chemicals that occur in nature but which have been extracted without changing their chemical composition.

Only the following processes comply with the definition of a naturally-occurring chemical.

If your chemical is extracted by some other means, such as steam distillation or solvent extraction, it will not be a naturally-occurring chemical but an industrial chemical.

i. Manual, mechanical or gravitational

  • Filtration—solid and liquid phases of a mixture are mechanically separated by passing it through a porous medium.
  • Centrifugation—liquid phases or solid and liquid phases of a mixture are separated by mechanical/gravitational means.
  • Sedimentation—solid and liquid phases of a mixture are gravitationally separated by enabling the settling of solids in liquids.
  • Cold pressing—liquid of a liquid-solid mixture is separated by squeezing it to obtain the liquid.
  • Sieving—solids in a mixture can be separated on the basis of particle size.

ii. Extraction by dissolution in water (for water-soluble chemicals)

  • Water is the only solvent that can be used to extract the chemical from other components in a mixture.
  • Examples include:
    • extraction of sugar from sugar beets using water
    • leaching of soluble tea from tea leaves, and
    • extraction of a water-soluble chemical from a mineral ore.
  • Dissolution by any other solvent or mixture of solvents (or mixture of water with other solvents) disqualifies the chemical from being naturally-occurring.

iii. Flotation

  • Flotation is a separation process used in mineral processing to separate minerals from waste rock or solids.
  • Mineral ore is pulverised and mixed with water and chemicals that cause preferential wetting of the solid particles.
    • The unwetted particles are carried to the surface by air bubbles to obtain a mineral concentrate—for example, lead, zinc, and copper concentrates.

iv. Heating for the sole purpose of removing uncombined water

  • Heat can be used to purify or concentrate chemical compounds by removing uncombined water, for example the drying of a wet clay or mineral, where moisture is not chemically bound to the substrate.
  • Using heat for any other purpose, such as steam distillation, disqualifies the chemical from being naturally-occurring.