Sodium hydrogen-5-sulphoisophthalate

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Persistence Assessment

The subject material was not readily biodegradable when tested in an OECD Guideline 301B test and displayed only 2% degradation after 28 days. It was also not biodegradable in a 20 -day BOD test conducted according to the EPA Method 405. There is no additional information on the persistence of the subject material in fresh or estuarine environments or in sediments or soils. There was less than a 10% change in the concentration of the test substance after 120 hours in an OECD 111 abiotic degradation test.  Based on the available information, it is is not possible to preclude that the subject material is a P or vP substance.

Bioaccumulation Assessment

There is no bioaccumulation data available for the subject material in an appropriate aquatic species.

The octanol/water partition coefficient was determined according to EU Method A.8 (Partition Coefficient) and OECD Guideline 107, and according to GLP. The logKow was estimated by potentiometric titration to be lower than (-1.7), at 23 deg C. EPIWIN KOWWIN (v1.68) estimates the logKow to be -7.33.

The QSAR methodology of Arnot and Gobas (2003) was used to assess the bioaccumulative potential of the subject material. This published method is well documented and is applicable to ionizable compounds, including those similar to the subject material and containing carboxylic and sulfonic acid functional groups. The subject material was assessed in this method for bioaccumulation potential in an upper trophic level freshwater fish considering either the presence or absence of biotransformation. In the case of assumed biotransformation, identical estimated BCF and BAF values were obtained for the subject material of 0.8938 L/kg wet-wt. If no biotransformation is assumed, the BCF and BAF values become 0.8972 and 0.8973 L/kg wet-wt, respectively. Based on this QSAR analysis, the subject material has a low potential for bioaccumulation.

Active and passive transport mechanisms might contribute to an increased potential for bioaccumulation (ECHA. Guidance on information requirements and chemical safety assessment. Chapter R.11: PBT Assessment. Appendix R.11 -1. November 2012). Passive transport would be most dependent on the ability to solubilize in and pass through the lipid membrane. For a chemical with a low measured LogPow, such as the subject material, passive diffusion is not expected. Active transport or carrier mediated processes could apply but such processes are generally quite molecule specific and are thus not generally operative. Filtration - or passage of molecules into cells through membrane channels - is generally active or possible only for molecules with molecular weights less than 100 g/Mol. Thus, a weight of evidence conclusion in the case of the current material would suggest that it will not readily pass across cellular membranes and is thus of low concern for bioaccumulation.

Toxicity Assessment

Based on significant developmental effects noted in an OECD 422 study in rats, the subject material receives a classification under the EU Dangerous Substance Directive (67/548/EEC) of Repr. Cat. 3; R63 (Possible risk of harm to the unborn child). Classification under the EU Regulation 1272/2008 results in a Repr. Cat. 2 (H361: Suspected of damaging fertility or the unborn child). Based on a Repr. Cat. 3; R63 classification, the subject material should be classified as toxic according to Annex XIII.

Summary and overall Conclusions on PBT or vPvB Properties

Based on the arguments and information presented above, the subject material would not be rated either as a PBT or vPvB substance.