Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Biodegradation

Sodium diisobutylnaphthalenesulphonate is like the longer alkyl chain fraction of aromatic hydrocarbons, C10-13, reaction products with branched nonene, sulphonated, sodium salts not expected to be readily biodegradable. For the half-life's in soil and sediment the default half-life's as suggested by REACH guidance R.16 will be used for risk assessment as a worst-case.

The biodegradation results as observed for aromatic hydrocarbons, C10-13, reaction products with branched nonene, sulphonated, sodium salts will be read across to the structural analogue Sodium diisobutylnaphthalenesulphonate.

The biodegradation potential of aromatic hydrocarbons, C10-13, reaction products with branched nonene, sulphonated, sodium salts has been assessed in an inherent test (SCAS test) in combination with Closed Bottle tests. The results reveal that methylnaphthalenesulphonate, and part of the isomers of dimethylnaphthalenesulphonate, degrade. The other constituents are not readily biodegradable. The substance is considered to be inherently degradable not fulfilling the specific criteria outlined in the REACH guidance.

 

Abiotic degradation

The substance is expected to be stable in the environment on the basis of the chemical structure.

Bioaccumulation

The bioaccumulation test on aquatic species is waived because the available information (log Kow and calculated BCF values) is deemed sufficient for the PBT assessment, classification and labelling and the chemical safety assessment. The log Kow of 0 and the chemical structure of the substance suggest a very low bioaccumulation potential. The calculated BCF is 3.16 L/kg wwt.

 

Adsorption/desorption

No sorption/desorption data is available for Sodium diisobutylnaphthalenesulphonate. The sorption data from a structurally similar substance aromatic hydrocarbons, C10-13, reaction products with branched nonene, sulphonated, sodium salts (source) is read across to Sodium diisobutylnaphthalenesulphonate (target).

This source substance has a slightly longer alkyl chain than the target substance; Sodium diisobutylnaphthalenesulphonate and is therefore expected to have a slightly stronger sorption. The use of the Koc of the source substance aromatic hydrocarbons, C10-13, reaction products with branched nonene, sulphonated, sodium salts can therefore be considered as a worst-case approach (will lead to higher PECsoil and sediment concentrations).

The log Koc of aromatic hydrocarbons, C10-13, reaction products with branched nonene, sulphonated, sodium salts of 3.5 was experimentally determined in an adsorption/desorption study according to OECD Guideline 121 under GLP conditions