Perfluorobutanesulfonic acid (PFBS) is a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

having a four-carbon fluorocarbon chain and a sulfonic acid

functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the re ...

. It is stable and unreactive because of the strength of

carbon–fluorine bond The carbon–fluorine bond is a polar covalent bond between carbon and fluorine that is a component of all organofluorine compounds. It is one of the strongest single bonds in chemistry (after the B–F single bond, Si–F single bond, and H–F ...

s. It can occur in the form of a colorless liquid or a corrosive solid. Its

conjugate base A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid donates a proton () to a base—in other words, it is a base with a hydrogen ion added to it, as in the reverse reaction it loses a ...

is perfluorobutanesulfonate (also called nonaflate) which functions as the

hydrophobe In chemistry, hydrophobicity is the physical property of a molecule that is seemingly repelled from a mass of water (known as a hydrophobe). In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, ...

fluorosurfactant Per- and polyfluoroalkyl substances (PFASs) are synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain. An early definition, from 2011, required that they contain at least one perfluoroalkyl mo ...

s. Since June 2003, 3M has used PFBS as a replacement for the persistent, toxic, and

bioaccumulative Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost or eliminated ...

compound

perfluorooctanesulfonic acid Perfluorooctanesulfonic acid (PFOS) (conjugate base perfluorooctanesulfonate) is a chemical compound having an eight-carbon fluorocarbon chain and a sulfonic acid functional group and thus a perfluorosulfonic acid. It is an anthropogenic (man-ma ...

(PFOS) in its

Scotchgard Scotchgard is a 3M brand of products, a stain and durable water repellent applied to fabric, furniture, and carpets to protect them from stains. Scotchgard products typically rely on organofluorine chemicals as the main active ingredient along ...

stain repellents. 3M markets surfactant with PFBS in two fluorosurfactants.

Safety

PFBS has a

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable at ...

of a little over one month in humans, much shorter than PFOS with 5.4 years. PFBS is persistent in the environment. Studies have not yet been specifically conducted to determine safety in humans. The ECHA decision adding PFBS and its salts to the

REACH Regulation Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) is a European Union regulation dating from 18 December 2006. REACH addresses the production and use of chemical substances, and their potential impacts on both human he ...

Candidate List of Substances of Very High Concern states:

“The combined intrinsic properties justifying the inclusion as a substance for which there is scientific evidence of probable serious effects to human health and the environment which give rise to an equivalent level of concern are the following: very high persistence, high mobility in water and soil, high potential for long-range transport, and difficulty of remediation and water purification as well as moderate bioaccumulation in humans. The observed probable serious effects for human health and the environment are thyroid hormonal disturbances and reproductive toxicity seen in rodents, and effects on liver, kidney and haematological system in rats, hormonal disturbances and effects on reproduction in marine medaka fish and effects on expression of hormone receptors in tadpoles. Together, these elements lead to a very high potential for irreversible effects.”

Legislation and Regulation

European Union

On 2020-01-16, PFBS and its salts were added to the

Candidate List of Substances of Very High Concern (SVHCs) on the grounds of "Equivalent level of concern having probable serious effects to human health (Article 57(f) - human health)" and "Equivalent level of concern having probable serious effects to the environment (Article 57(f) - environment)".

United States

There is no national standard for PFBS. However, several states have proposed regulating PFBS in drinking water including

Michigan Michigan () is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the List of U.S. states and ...

either as contamination standards, guidance or health advisories. In 2020 Michigan adopted drinking water standards for 5 previously unregulated PFAS compounds, including PFBS which has a maximum contaminant level (MCL) of 420 parts per trillion (ppt).

References

{{reflist Anionic surfactants Perfluorosulfonic acids

Safety

Legislation and Regulation

European Union

United States

See also

References