Sulfuric acid, mono-C12-18-alkyl esters, sodium salts

Endpoint summary

Description of key information

Oral LD50 (OECD guideline 401), rat = 4010 mg/kg bw
Dermal LD50 (OECD guideline 402), rabbit > 2000 mg/kg bw (limit test) 
Acute toxicity by inhalation was not tested according to REGULATION (EC) No 1907/2006, Annex VIII, Section 8.5, Column 2.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

4 010 mg/kg bw

Quality of whole database:

The whole data base is conclusive and of high quality.

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

The whole data base is conclusive and of high quality.

Additional information

There are several acute oral toxicity studies but no data on acute dermal toxicity for C12-18AS Na (CAS 68955-19-1) available. Therefore the endpoint acute dermal toxicity is covered by read across from structurally related alkyl sulfate (AS), i.e. C10-16AS NH4 (CAS 68081-96-9), C10-16AS Mg (CAS 68081-97-0), C12-13AS K (CAS 91783-22-1) and C8AS Na (CAS 142-31-4). 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.

Acute oral toxicity

The key acute oral study was conducted with C12-18AS Na (CAS 68955-19-1, analytical purity 25%) on Cox CD rats (P&G, 1974) similar to OECD Guideline 401. The test substance was applied to 5 animals per sex per group at doses of 2500, 3500, 4900 and 6850 mg/kg bw via gavage. The post observation period comprised 14 days. Following mortalities were observed within the different dose groups: 0/10, 5/10, 6/10 and 10/10. Clinical signs of toxicity comprised slight to moderate decreased motor activity and respiratory rate, blanching, abdominal griping and diarrhea at 2500 mg/kg bw, slight haemorrhagic rhinitis which persisted up to seven days post treatment at 3500 and 4900 mg/kg bw and of slight loss of corneal reflex and pupillary responses at 6850 mg/kg bw. No findings were observed upon necropsy. The LD50 was given as 4010 mg/kg bw based on active ingredient.

Another acute oral study with C12-18AS Na (CAS 68955-19-1, analytical purity 30%) was conducted on Wistar rats (Potokar, 1989) similar to OECD Guideline 401. The test substance was applied to 5 animals per sex per group at 2000 mg/kg bw via gavage. No mortality, no clinical signs of toxicity and no effects on body weight or upon gross pathology were observed. Thus, the LD50 was > 2000 mg/kg bw based on test material and > 600 mg/kg bw based on active ingredient.

C12-18AS Na (CAS 68955-19-1, analytical purity 30%) was applied to 5 Sprague Dawley rats per sex per group (Cawley, 1977) at 500 mg/kg bw/d via gavage. No mortality and no clinical signs of toxicity were observed. Thus, the LD50 was > 500 mg/kg bw based on test material. The dose level was based on a preliminary range-finding study with 1 male and female rat at 1, 50, 500, 5000, 15000 mg/kg bw. Mortality was observed at 5000 and 15000 mg/kg bw. The application volume at the two highest dose groups was 30 mL/kg bw and 10 mL/kg bw for the other dose groups. Based on the available data no LD50 can be derived from this study.

In another study C12-18AS Na (CAS 68955-19-1, analytical purity 35%) was applied to rats via the oral route (not further specified) and revealed an LD0 > 5000 mg/kg bw (Potokar, 1981).

In conclusion the weight of evidence approach supports the assumption that C12-18AS Na (CAS 68955-19-1) does not fulfil the criteria for classification for acute oral toxicity.

Acute dermal toxicity

Regarding the acute dermal toxicity four relevant studies are available for the read-across substances C10-16AS NH4 (CAS 68081-96-9), C10-16AS Mg (CAS 68081-97-0), C12-13AS K (CAS 91783-22-1) and C8AS Na (CAS 142-31-4).

The key study was conducted with C8AS Na (CAS 142-31-4) according to OECD Guideline 402 (BASF, 2012). 5 Wistar rats per sex were treated with 2000 mg/kg bw under semi occlusive conditions for 24 h. No mortality occurred, no sign of systemic toxicity and of local irritation was observed.

The study conducted with C10-16AS NH4 (CAS 68081-96-9) was performed as limit test similar to OECD Guideline 402 with 3 male and 3 female New Zealand White rabbits (Frank, 1975a). The test substance (analytical purity 25.1%) was applied at 2000 mg/kg bw for 24 h under occlusive conditions. No mortalities occurred. Clinical signs of toxicity comprised of severe erythema and slight eschar formation at 24 h, necrosis by day 2–14 with sloughing of the skin by day 8–14 and hyper-pigmentation of new skin by day 14. No signs of systemic toxicity were observed. Hence, the LD50 value is greater than 2000 mg/kg bw based on the test material and greater than 500 mg/kg bw based on the active ingredient.

The study conducted with C10-16AS Mg (CAS 68081-97-0) was performed as limit test similar to OECD Guideline 402 with 3 male and 3 female New Zealand White rabbits (Frank, 1975b). The test substance (analytical purity 23.5%) was applied at 2000 mg/kg bw for 24 h under occlusive conditions. No mortalities occurred. Clinical signs of toxicity comprised of severe erythema and eschar formation at 24 h, necrosis by Day 5–21 and necrotic tissues sloughed and leaving skin hyper-pigmented at Day 21. Hence, the LD50 value is greater than 2000 mg/kg bw based on the test material and greater 500 mg/kg bw based on the active ingredient.

Another study similar to OECD Guideline 402 was performed with C12-13AS K (CAS 91783-22-1) on three male and three female New Zealand White rabbits (Benedict, 1978). Both sexes were dosed at 2000 mg/kg bw (analytical purity 25%) under occlusive conditions for 24 h. No mortalities occurred during the conduct of the study. Findings within this study comprised of moderate to severe erythema, edema, and atonia, desquamation and fissuring by day 6 and eschar formation and exfoliation. Based on the above mentioned findings the LD50 is greater than 2000 mg/kg bw based on the test material and greater 500 mg/kg bw based on the active ingredient.

In conclusion the data justify a non-classification of C12-18 AS Na (CAS68955-19-1) for dermal acute toxicity.

Acute inhalation toxicity

No studies for acute inhalation toxicity are available. However, testing the potential of acute toxicity via inhalation route of C12-18AS Na (CAS 68955-19-1) is considered to be not justified. According to Regulation (EC) No 1907/2006, Annex VIII, Section 8.5, Column 2, in addition to the oral route (8.5.1), for substances other than gases, the information mentioned under 8.5.2 to 8.5.3 shall be provided for at least one other route. As information under 8.5.3 (dermal route) is provided, the requirement is fulfilled by using the most appropriate route of exposure.

AS is mainly used in liquid media and due to its very low vapour pressure [2] inhalation is not viewed as a significant route of exposure. Inhalation of AS may occur by inhalation of aerosols generated by spray cleaners or by inhalation of detergent dusts (e.g. washing powder). Taken into account that the acute toxicity of AS is generally low no further information on acute toxicity is expected by testing for acute inhalation toxicity as the predominant effect will comprise of local irritant effects rather than systemic toxicity.

 

[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 acute toxicity – oral endpoint
A reliable study conducted similar to OECD Guideline 401 was chosen. No mortality was observed at 2000 mg/kg bw/d.

Justification for selection of acute toxicity – inhalation endpoint
Acute toxicity by inhalation was not tested according to REGULATION (EC) No 1907/2006, Annex VIII, Section 8.5, Column 2.

Justification for selection of acute toxicity – dermal endpoint
The key study with pure test item was chosen.

Justification for classification or non-classification

The available data on acute oral and dermal toxicity do not meet the criteria for classification according to Regulation (EC) 1272/2008 or Directive 67/548/EEC, and are therefore conclusive but not sufficient for classification.