Bisphenol

Not to be confused with biphenol.

The bisphenols (/ˈbɪsfɪnɒl/) are a group of industrial chemical compounds related to diphenylmethane; commonly used in the production of plastics and epoxy resins. They feature two hydroxyphenyl groups linked by a methylene bridge. Also included are bisphenol S, P, and M. "Bisphenol" is a common name; the letter following denotes the variant, which depends on the additional substituents. Bisphenol A is the most common representative of the group, with millions of metric tons produced globally in the past decade, often simply called "bisphenol".^[1]

Bisphenols have attracted controversy because of their role as endocrine disruptors. Their estrogenic properties are weak, but the scale of their production is considerable.^[2][3]

Partial inventory of bisphenols

Structural formula	Name	CAS	Reactants
	Bisphenol A	80-05-7	Phenol	Acetone
	Bisphenol AP	1571-75-1	Phenol	Acetophenone
	Bisphenol AF	1478-61-1	Phenol	Hexafluoroacetone
	Bisphenol B	77-40-7	Phenol	Butanone
	Bisphenol BP	1844-01-5	Phenol	Benzophenone
	Bisphenol C	79-97-0	o-cresol	Acetone
	Bisphenol C 2	14868-03-2	Phenol	Chloral
	Bisphenol E	2081-08-5	Phenol	Ethanal
	Bisphenol F	620-92-8	Phenol	Formaldehyde
	Bisphenol G	127-54-8	2-Isopropylphenol	Acetone
	Bisphenol M	13595-25-0
	Bisphenol S	80-09-1	Phenol	Sulfur trioxide
	Bisphenol P	2167-51-3
	Bisphenol PH	24038-68-4	2-Phenylphenol	Acetone
	Bisphenol TMC	129188-99-4	Phenol	3,3,5-Trimethylcyclohexanone
	Bisphenol Z	843-55-0	Phenol	Cyclohexanone
	Dinitrobisphenol A	5329-21-5	Bisphenol A	Nitric acid
	Tetrabromobisphenol A	79-94-7	Bisphenol A	Bromine
	Tetramethyl bisphenol F	5384-21-4	2,6-Xylenol	Formaldehyde

Health effects

Bisphenols A (BPA), F (BPF) and S (BPS) have been shown to be endocrine disruptors, potentially relating to adverse health effects.^[2][4] Other implicated health effects include obesity and metabolic disorders.^[5]The threat is of interest because the chemical is pervasive in everyday life, inclluding food^[2] and thermal paper.^[6]

Occurrence in humans

Bisphenols have monitored in humans through analysis of serum and urine.^{[7] [8]} Workers who manufacture BPA-based thermal paper have high BPA levels.^[6]. BPS and BPF levels are elevated among workers dismantling e-waste in China.^[9]

Many analogues of BPA, such as bisphenol F (BPF), bisphenol S (BPS), bisphenol AP (BPAP), bisphenol AF (BPAF), bisphenol FL (BPFL), and bisphenol C (BPC) are less studied with respect to their hormone-disrupting potential and other health effects.^{[10][5][11][12]}

Biodegradation

Due to its high production volumes, BPA has been characterised as "pseudo-persistent",^[13] leading to its spreading and potential accumulation in a variety of environmental matrices. BPA has a fairly short half-life. A number of aerobic organisms degrade BPA.^[14][15]

Precautions

Engineering controls have been applied such as process enclosure, local exhaust ventilation, and isolation of bisphenol-handling areas lower airborne and surface contamination in workplaces where bisphenols are used.^[16][17].

Exposure to Bisphenol

Because bisphenol are largely used in everyday life such as in plastics, protective coating of packages, inner lining of food containers, and thermal paper of receipts, it can enter the body through multiple pathways.^[18]

Exposure Pathways

Dietary Exposure

The main pathway of exposure is through ingestion of food that is contaminated with bisphenol. Bisphenol can leach slowly into the food from things like the inside lining of cans, plastic containers, packages, disposable tableware, and especially through wear and tear. ^[19] This means that even simply using or eating food that came in contact with product made from bisphenol could result in exposure. ^[20] Moreover, studies have found bisphenol residue in foods and beverages even when using containers that claimed to be "bisphenol free".^{[20] [21] [22]}

Dermal (Skin) Exposure

Bisphenol can also enter the body through the skin via absorption, and can result in skin irritation or allergic reactions in some individuals.^[19][23] One well-known example is the handling of store receipts, which are often coated with bisphenol, and can transfer from the skin of the hands to the mouth, resulting in ingestion of the chemical.^[24] Workers who handle receipts regularly, like cashiers and retail employees, may face higher dermal exposure.^{[19] [25]}

Inhalation Exposure

Due to its volatility, bisphenol do not easily evaporate into the air at room temperature according to their chemical properties.^[25][23] However, bisphenol can attach to dust an small particles in the environment and be inhaled. Usually, inhalation exposure of bisphenol are more common under industrial and manufacture settings. ^[26][18][27]