Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

The aromatic sulphonic acids are soluble in water and are neither sorptive, nor volatile, nor bioaccumulative. These substances completely ionise in water even at low pH. The salts of these acids are the hydrotropes. In total, 14 biodegradation studies - 7 with the acid forms and 7 with the salt forms - support a conclusion of ready biodegradability. These substances are neither hydrolysable nor photolysable. In summary, the aromatic sulphonic acids are not persistent and they and their salt forms should partition primarily to the water compartment

The studies with the salts (hydrotropes) provide valid read-across for the acids. The specific cation is not expected to have an appreciable effect on fate, ecotoxicity or mammalian toxicity and therefore the dataset for the entire hydrotropes category can be applied broadly. 

The aromatic sulphonic acids are almost completely ionized in watery environments even at low pH. The salts of these acids are the hydrotropes (or “sulphonates”) which include ammonium, calcium, potassium and sodium cations. In principle the salts get dissociated when in contact with water, so forming back to the acids. Because of their close chemical similarities and because much of the production of the aromatic sulphonic acids goes to manufacturing the salts, the extensive dataset for the hydrotropes can also be used as a source of read-across for endpoints in an aromatic sulphonic acid dossier. This is particularly relevant for studies that are conducted in water (e.g., ecotoxicity and biodegradation) as well as for mammalian toxicity studies where the relatively high acidity of the acid form has an immediate and harsh local effect, whereas the salt form provides an indication of potential systemic toxicity beyond the site of application or initial contact