Phenol is an oxygenated derivative of benzene, usually produced from coal tar, used in painting and in the manufacture of certain plastics and medicines. Phenols and alcohols are formally similar, but their chemical reactions are largely different. Phenols show acidity in water.

Phenols, which are hydroxy derivatives of benzene, can be found in wastewaters, natural waters or in water basins for drinking water supply in domestic or industrial plants. Chlorination studies to clean these waters lead to the formation of chlorophenols having an odor and unpleasant taste in water.

A number of methods for phenol determination are applied by authorized laboratories. Phenols in wastewater can be decomposed by biological and chemical oxidation in a short time. For this reason, measurements should be made and evaluated within four hours after sampling. If immediate measurements cannot be made, samples can be stored for a maximum of 24 hours under appropriate conditions. When sampling wastewater, laboratories comply with TS EN ISO 5667-3 Water quality - Sampling - Section 3: Complies with guidelines for the storage, transport and storage of water samples

It is not possible to find relative amounts of various phenolic compounds in a water sample. Thus, phenolic compounds in the water sample are defined as phenol. Phenol refers to the minimum concentration of phenolic compounds present in the sample.

Phenol and phenol derivatives are quite common in industrial wastes. Because phenols are toxic, they harm all living things. Phenol in water is understood as smell and taste. Drinking water containing phenol causes discomfort in the human body. It is possible to remove phenolic compounds by physical, chemical and biological methods.

The laboratories providing these services based on their authority in national and international accreditation organizations are based on the standards published by Turkish Standards Institute in their measurement and evaluation studies.