Benzenesulfonic acid, 4-C20-24 (even numbered) sec-alkyl derivs., sodium salts

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

An evaluation of the inherent properties of the test substance is performed against the ANNEX XIII criteria. If insufficient data were available, the screening criteria as laid down in ECHA Guidance on information requirements and chemical safety assessment Chapter R.11: PBT Assessment (2014) were applied.

 

The persistency assessment is based on the screening criteria in Annex XIII of the REACH Regulation. The biodegradation potential of the test substance was assessed using QSAR with the Biowin v4.10 plug-in from EPISUITE v4.1 from US EPA. The Biowin 3 result is "weeks_months" and the Biowin 5 probability is less than 0.5; therefore the prediction is not readily biodegradable. In addition, Biowin 6 also predicted to be not readily biodegradable, corresponding to a degradation in the OECD 301C test. In conclusion, it's expected that the substance is not readily biodegradable. Further, the substance displays properties that indicate persistency within the environment. Due to the extremely low water solubility (1.649e-05 mg/L, QSAR with the WSKOW v1.42 plug-in from EPISUITE v4.1 from US EPA), hydrolysis of the substance is unlikely to occur. As such, the substance fulfils the requirements of Annex XIII, Paragraph 1.1 based on evaluation of available data, and can be considered to be P and vP based in this data. It can therefore be concluded that based on the criteria mentioned above the substance is potentially P/vP.

 

The bioaccumulation assessment is based on the screening criteria in Annex XIII of the REACH Regulation. The bioaccumulation potential of the test substance was assessed using QSAR with the Kowwin v1.68 plug-in from EPISUITE v4.1 from US EPA. The Kowwin result is a partition coefficient (Log Kow) of 8.82. A partition coefficient in excess of 4.5 is considered to be of concern as potential for bioaccumulation, according to screening criteria for bioaccumulation in ECHA guidance (Chapter R.11 PBT Assessment). The likely reliability of the log Kow is, however, considered to diminish above a value of 6, as noted in Appendix R.11-1 Annex 1 of ECHA guidance on PBT Assessment. Substances with log Kow between 4.5 and 6 are considered likely to be highly accumulating; however no substantial bioconcentration is assumed for compounds having log K ow with values less than 4.5 or greater than 6.  For compounds having log Kow greater than 6, a gradual decrease of the BCF is observed and it has been hypothesised within the published literature that a high log Kow is more an effect of solubility than a tendency of the substance to be lipophilic. This is further supported by the estimation based on EPIWIN that the log BCF was determined to be 0.6 (BCF = 3.978 L/kg wet-wt), considerably below the threshold of concern derived by the REACH criteria of 2000 (B) and 5000 (vB). The available evidence on the bioaccumulation potential for the substance indicates that the screening criteria for bioaccumulation potential (B and vB) are not met. The substance is therefore concluded not to have a bioaccumulative potential (not B / not vB).  

 

The toxicity assessment is based on the screening criteria in Annex XIII of the REACH Regulation. No ecotoxicological and toxicological data are available on the test substance. Read-across was done with LABS Na as the source substance based on a worst-case approach. The target substance is very likely not acutely toxic to aqueous organisms, as it is expected that the obtained no effect concentration (NOEC) would be at or above the maximum concentration exposed to the organisms. The source substance for the read-across is not classified as carcinogenic (Cat. 1 or 2), as mutagenic (Cat. 1 or 2), or as reproductive toxicant (Cat. 1, 2, or 3), nor as STOT RE Cat. 1 or 2 according to the Regulation EC N° 1272/2008. The same is assumed for the target substance. As such, based on evaluation of available data, the test substance cannot be considered to be “T”. Hence, it does not fulfill the criteria to be considered as Toxic (not T).

 

Taking into account the conclusions that the substance is potentially P/vP, not B/vB and not T, the substance should not be considered as a PBT/vPvB substance.