Sulfuric acid, mono(C16-18 and C18-unsatd. alkyl) esters, sodium salts

Endpoint summary

Description of key information

skin irritation (OECD 404): irritating
eye irritation (OECD 405): highly irritating/corrosiv
SCLs according to GHS:
>10% - <=20% Eye Irrit. Cat.2, R36
<= 10% No Classification

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

There is no study regarding skin and eye irritation/corrosion with C16-18 and 18 unsaturated AS Na (CAS 1394155-71-5) available. Therefore this endpoint is covered by read across to structurally related alkyl sulfates (AS) for weight-of-evidence approach, i.e. C12-18AS Na (CAS 68955-19-1) for skin irritation and C12-16 AS Na (CAS 73296-89-6), C10-16AS Na (CAS 68585-47-7) and C12-13AS K (CAS 91783-22-1) for eye irritation.The possibility of a read-across to other alkyl sulfates in accordance with Regulation (EC) No 1907/2006 Annex XI 1.5. Grouping of substances and read-across approach was assessed. In Annex XI 1.5 it is given that a read-across approach is possible for substances, whose physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity. The AS reported within the AS category show structural similarity. The most important common structural feature of the category members is the presence of a predominantly linear aliphatic hydrocarbon chain with a polar sulfate group, neutralized with a counter ion. This structural feature confers the surfactant properties of the alkyl sulfates. The surfactant property of the members of the AS category in turn represent the predominant attribute in mediating effects on mammalian health. Therefore, the AS of the AS category have similar physico-chemical, environmental and toxicological properties, validating the read across approach within the category. The approach of grouping different AS for the evaluation of their effects on human health and the environment was also made by the OECD in the SIDS initial assessment profile [1] and by a voluntary industry programme carrying out Human and Environmental Risk Assessments (HERA [2]), further supporting the read across approach between structurally related AS.

Skin irritation 

There is one relevant study for the read-across substance C12-18AS Na (CAS 68955-19-1) available addressing skin irritation.

The key study conducted with Na C12-18 ASO4 (CAS 68955-19-1) was performed according to OECD Guideline 404 under semi-occlusive conditions (Pels Rijcken, 1994). Each of three New Zealand White rabbits was exposed for 4 h to 0.5 g of the unchanged test item and was observed for a period of 14 days for erythema and edema. The mean erythema score (24, 48 and 72 h reading) and the mean edema score were 3 and 2.3, respectively. Both effects were fully reversed within the 14 days observation period. Thus the test substance was classified as skin irritating Category 2 according to Regulation 1272/2008/EC and R38 according to Directive 67/548/EEC within this study. As the neat substance has to be classified as skin irritating, the substance will also be classified as “may cause respiratory irritation” (STOT SE3, H335 and R37, respectively) in case the substance is available as neat powder.

Eye irritation

There is one relevant study for the read-across substance C12-16AS Na (CAS 73296-89-6) available addressing eye irritation.

An OECD guideline 405 study was performed with 0.1 mL pure Na C12-16 ASO4 (CAS 73296-89-6, analytical purity 30%) on three New Zealand White rabbits (Tortajada, 1997). The observation period was 21 days. Eye reactions were scored 1, 24, 48 and 72 h after treatment. Further observations were performed on days 7, 14, and 21 after application. The mean (24, 48 and 72 h reading) cornea, iris, conjunctivae and chemosis scores were 1, 0.2, 2.8 and 3.6. The iritic effects reversed within 72 h and chemosis within the 21 day observation period. The effects observed on cornea and the redness of the conjunctiva was not fully reversible within 21 days. Thus the substance produced irreversible effects on the eye at a concentration of 30% within this study.

Setting of SCLs for eye irritation

As corrosion and irritation depends on the concentration of the substance in a solvent, further studies with lower concentrations of the test substance were also considered to assess whether specific concentration limits can be set. For this purpose, one study with C12-13AS K (CAS 91783-22-1) and two studies with C10-16AS Na (CAS 68585-47-7) with a concentration range of 10 to 22% were evaluated.

In the study with C12-13AS K (CAS 91783-22-1, analytical purity 44%) 0.1 mL of the diluted test item (1:1 mixture with water) was applied to one eye of each of three New Zealand White rabbits according to OECD guideline 405 (Braun, 1978) without rinsing. In a second experiment with additional 3 rabbits the procedure was repeated but the treated eye was rinsed with 20 mL of lukewarm tap water 4 seconds after application of the test item. The eye reactions were recorded 1, 24, 48, 72 h and 4, 7, 14, 21 and 28 days in both experiments. The mean (24, 48 and 72 h reading) cornea, iris, conjunctivae and chemosis scores of experiment 1 were 2, 0.8, 2.1 and 1.7. The findings reversed in 2/3 animals within 14 days while 1/3 animals showed signs of irritation after 21 days. However, the signs of irritation show a clear tendency to decrease with time. No reading on day 28 was possible. Findings in the experiment with rinsing of the eye were less pronounced but irritating properties were also observed. As the ocular findings clearly reversed within 21 days the result of the study indicate the concentration of 22% to be the turning point between classification as severe damage to the eye and eye damaging.

The first study with 0.1 mL undiluted C10-16AS Na (CAS 68585-47-7, analytical purity 10%) was performed similar to OECD guideline 405 (Kukulinski, 1980) on three New Zealand White rabbits with an observation period of 7 days. The mean (24, 48 and 72 h reading) cornea, iris, conjunctivae and chemosis scores over all animals were 1.4, 0.7, 2 and 1.6. Corneal opacity was still observed in 1/3 animals (scored 1) and conjunctival redness was still present in 2/3 animals (both scored 1) upon reading at day 7. Depending on the classification requirements the test substance is not or only moderate irritating to the eye at a concentration of 10%.

The second study with C10-16AS Na (CAS 68585-47-7, analytical purity 10%)was performed similar to OECD guideline 405(Kukulinski, 1980).0.1 mL of the undiluted test item was instilled into one eye of each of three New Zealand White rabbits. Eye reactions were scored at least 24, 48 and 72 h and 14 days after application of the test item. The mean (24, 48 and 72 h reading) cornea, iris, conjunctivae and chemosis scores were 0.9, 0.7, 1.9 and 1.6. All findings were fully reversible within the observation period. Thus, the test substance showed no eye irritating properties at a concentration of 10%.

Based on the above mentioned results with different concentrations of structurally related alkyl sulfates a cut of value for classification as severe irritating to eyes is set at a concentration of 20% and for classification as irritating at a concentration of 10%.

 

[1] SIDS initial assessment profile, (2007);
http://www.aciscience.org/docs/Alkyl_Sulfates_Final_SIAP.pdf

[2] (HERA Draft report, 2002);
http://www.heraproject.com/files/3-HH-04-%20HERA%20AS%20HH%20web%20wd.pdf

Justification for selection of skin irritation / corrosion endpoint:
Reliable OECD guideline study.

Justification for selection of eye irritation endpoint:
Reliable OECD guideline study.

Effects on skin irritation/corrosion: irritating

Effects on eye irritation: highly irritating

Justification for classification or non-classification

According to the classification criteria of Directive 67/548/EEC and Regulation (EC) No 1272/2008 the test substance needs to be classified with Xi, R38/R41 and Skin Irrit. 2, H315 and Eye Dam.1, H318, respectively.

It could be shown with experimental data on eye irritation that above 10 to 20% active substance only the classification Eye Irritating Category 2 according to Regulation (EC) No 1272/2008 and according to Directive 67/548/EEC only the classification R36 remains. At and below 10% active substance no classification at all is necessary. Hence, the Generic Concentration Limits (GCLs) can be substituted by the mentioned specific ones (SCLs).