Reaction product of Benzenesulfonic acid, 4-C10-13-sec-alkyl derivs. and Benzenesulfonic acid, 4-methyl- and sodium hydroxide

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Summary and overall conclusions: Marlon ARL can be characterised as reaction product of benzenesulfonic acid, 4-C10-13-alkyl derivatives and benzenesulfonic acid, 4-methyl- and sodium hydroxideealkenes C11-12 hydroformylation products. The substance does not fulfil the screening criteria for persistence, bioaccumulation or toxicity and hence does not meet the PBT or vPvB criteria. No further testing is required.

Persistence Assessment (P): The reaction product Marlon ARL and the substances that comprise the reaction product (i.e., the sodium linear alkybenzenesulfonate [LAS] and the sodium toluene sulphonate [a hydrotrope]) are soluble in water and are neither sorptive, nor volatile. The substances are expected to partition primarily to the water compartment where they are readily biodegradable and are not considered to be persistent in the environment. The evidence from experimental studies presented in this dossier is described below: Adsorption Experimental data are available for adsorption/desorption for the primary constituent, linear alkylbenzenesulfonate (LAS), although no data are available for the product Marlon ARL. The Kp for commercial LAS was 2,500 L/kg with a log Kp of 3.4 in activated sludge batch experiments. The log Pow for Marlon ARL was calculated according OECD Guideline 107 and determined to be 0.7 at 20 °C. It is reasonable to assume that based on this evidence the product Marlon ARL is unlikely to adsorb to sediment or soil compartments in the environment. Biodegradation The reaction product and the two substances that comprise the reaction product (i.e., the sodium salt of linear alkylbenzenesulfonate and sodiumtoluene sulphonate) are readily biodegradable, as described below:

• The Reaction Product: A 1993 EU DOC Die Away Test comparable to OECD 301A test where the test substance reached 94% DOC removal after 28 days and reached >70% biodegradation in 10 days after reaching 10% degradation;

• The main constituent (and read across substance) sodium 4-undecylbenzenesulfonate (CAS No 68411-30- 3): A 2002 OECD 301B Modified Sturm Test based on CO2 evolution where the test substance reached 85% CO2 evolution in 29 days and reached the 60% "ready biodegradability" threshold in 9 to 12 days; and

• The second constituent (and read across substance) sodium toluene sulphonate (CAS No 12068-03-0): A 2004 OECD 301B Modified Sturm Test based on CO2 evolution study where the test substance reached 100-115% CO2 evolution in 28 days and reached the 60% "ready biodegradability" threshold in 4 days.

A further six guideline biodegradation tests for hydrotrope substances closely related to sodium toluene sulphonate support these key studies and confirm the ready biodegradability of Marlon ARL. In addition, although the reaction product met the biodegradation screening test criteria, field study data for LAS are included in the dossier to demonstrate degradation in sediment and soil. These studies concluded a 11.6 day half-life in sediment and a 14 day half-life for the reaction product. In summary, Marlon ARL can be regarded as readily biodegradable, unlikely to adsorb to sediments or soil, and does not fulfil the criteria for Persistence (P).

Bioaccumulation Assessment (B): According to Annex XIII of Regulation (EC) No 1907/2006 and to the Guidance on information requirements and chemical safety assessment Chapter R.11 (PBT Assessment, ECHA (2008)), a substance does not fulfil the criteria “bioaccumulative (B)” or “very bioaccumulative (vB)” if the bioconcentration factor (BCF) is below 2000 or 5000 respectively or if the log Kow is below 4.5. The log Pow for Marlon ARL was determined according OECD Guideline 107 to be 0.7 at 20 °C. Published studies for the two substances that comprise the reaction product Marlon ARL (i.e., linear alkylbenzenesulfonate and sodium toluenesulfonate [a hydrotrope]) provide read across support for low bioaccumulation potential. In both tests the measured BCF value was reported as either aquatic or terrestrial compartments. In conclusion, as Marlon ARL cannot be regarded as bioaccumulative in aquatic, sediment or terrestrial organisms, Marlon ARL does not fulfil the criteria “bioaccumulative (B)” or “very bioaccumulative (vB)”. According to ECHA Guidance on information requirements and chemical safety assessment (May 2008), Chapter R.11, Figure 11-2: Integrated testing strategy for B-assessment, no further testing is required to conclude on the bioaccumulation criterion.

Toxicity Assessment: For completeness the toxicity assessment is discussed here, although a toxicity assessment is not required if the P and B criteria have not been met (see above). According to Annex XIII of Regulation (EC) No 1907/2006 and according to the Guidance on information requirements and chemical safety assessment Chapter 11 (PBT Assessment, May 2008), a substance does not fulfill the T criterion if the NOEC for marine or freshwater organisms is 0.01 mg/l or higher and if there is no evidence of chronic toxicity considering human health and no classification as carcinogenic (category 1 or 2), mutagenic (category 1or 2) or toxic for reproduction (category 1, 2 or 3) according to Directive 67/548/ECC. Human health data for the primary constituent, linear alkylbenzenesulfonate (LAS), of the reaction product are not considered to be significantly hazardous to human health under most conditions. The acute toxicity of Marlon ARL and LAS were comparable, oral LD50s of 2240 and 1080 mg/kg respectively, and dermal LD50s of 2000 for each of the substances. LAS was therefore used as a read across substance for the assessment of mammalian toxicity. Significant irritation effects were observed in acute skin and eye irritation studies when tested with undiluted 100% doses. These effects were sufficient for classification as category 2 and 1 for skin and eye irritation, respectively, under the CLP criteria. When the undiluted dose was quickly rinsed, effects were still observed but were reversible within 7 to 14 days. Mortality was not observed in repeated dose studies; effects seen were reduced body weight gain, either reductions or increases in organ weights, and enzymatic activity effects. No significant effects were observed in a reproductive toxicity study at the highest dose tested (350 mg/kg bw/d). Effects in two developmental studies were only observed at doses that were maternally toxic. In addition, mutagenicity studies using both in vitro and in vivo methods demonstrate that LAS was not mutagenic. LAS is classified as a category 4 oral toxicant, a category 2 skin irritant, and a category 1 eye irritant under the CLP regulation. In the environmental compartment, the lowest acute data point for Marlon ARL was a 96-hr LC50 of 5.5 mg/L for fish (Diefenbach, 1998). A calculated NOEC from a model ecosystem study for the major constituent of Marlon ARL (i.e., the read across substance LAS) was used as the basis for the derivation of the PNECaqua freshwater, where the NOEC was 0.268 mg/L. A significant distribution into sediments is not expected for the reaction product as it is readily biodegraded and has a very low logPow of 0.7 (Spilker, 2010), however three sediment toxicity studies were included in the dossier where the most sensitive NOEC value for the most sensitive species, Lumbriculus sp., exposed to LAS in sediments was 81 mg/kg (Comber et al., 2002). Similarly, soil organisms are not expected to be exposed to the reaction product but an HC5 value of 35 mg/kg soil dw based on 9 invertebrate and 12 plant studies was derived by Jensen et al., (2007). Exposure to birds is not expected and data from toxicity studies with mammals demonstrate Marlon ARL to be of low oral toxicity. In addition, the very low logPow of 0.7 (Spilker, 2010) means that bioaccumulation is not expected to occur through the food chain. In summary, Marlon ARL cannot be regarded as toxic to aquatic, sediment or terrestrial organisms and does not fulfil the toxicity (T) criterion as laid down in Annex XIII of regulation (EC) No 1907/2006.

PBT Assessment:

Persistence: Marlon ARL is unlikely to adsorb to sediments or soil and is readily biodegradable in the environment; it does not fulfil the criteria for Persistence (P).

Bioaccumulation: Marlon ARL cannot be regarded as bioaccumulative in aquatic, sediment or terrestrial organisms and does not fulfil the criteria “bioaccumulative (B)” or “very bioaccumulative (vB)”.

Toxicity: Read-across data to Marlon ARL (from LAS) did not meet the toxicity (T) criterion for human health and based on reliable environmental data, Marlon ARL cannot be regarded as toxic to aquatic, sediment or terrestrial organisms and does not fulfil the toxicity (T) criterion as laid down in Annex XIII of regulation (EC) No 1907/2006. The overall conclusion is that Marlon ARL does not meet the PBT or vPvB criteria. No further testing is required.