Sodium alkyl sulphate

Endpoint summary

Description of key information

Oral LD50 (OECD guideline 401), rat = 1000 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:

adverse effect observed

Dose descriptor:

LD50

Value:

1 000 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 no data regarding the acute toxicity of C12-13AS Na (CAS 1231880-35-5) available. Therefore the endpoint acute toxicity is covered by read across to structurally related alkyl sulfates (AS), i.e. C12-13AS Na (CAS 91783-23-2) for acute oral toxicity and 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) for the dermal route. 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. The AS of the AS category also 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 

A study performed similar to OECD Guideline 401 was conducted with C12-13AS Na (CAS 91783-23-2, analytical purity 26.8%). Five Wistar rats of each sex were dosed with the test substance at 880, 1040, 1260 and 1500 mg/kg bw via gavage and observed for mortalities for 14 days (Sasol, 1984). At the lowest dose no mortalities occurred. In the 1040, 1260 and 1500 mg/kg bw dose groups 0/5, 3/5 and 5/5 males and 2/5, 5/5 and 5/5 females died within 14 days. No data on clinical signs of toxicity are available. The LD50 was determined to be 1230 mg/kg bw for males and 1063 mg/kg bw for females.

Acute dermal toxicity

Regarding the acute dermal toxicity four 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 conducted 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 severe erythema and slight eschar formation at 24 h, necrosis on day 2–14 with sloughing of the skin on 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 active ingredient.

The study conducted with C10-16AS Mg (CAS 68081-97-0) was performed as limit test conducted 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 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 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 was greater than 2000 mg/kg bw based on test material and greater 500 mg/kg bw based on active ingredient.

Within the studies mentioned above no mortalities or signs of systemic toxicity occurred after dermal application of alkyl sulfates with varying carbon chain length. Taken into account the generally low toxicity after oral application and the low dermal absorption rate of alkyl sulfates (approx. 1%) this result was expected. In agreement, no classification for acute dermal toxicity is required. For details on absorption please refer to section Toxicokinetics, metabolim and distribution.

Acute inhalation toxicity

No studies for acute inhalation toxicity are available. However, testing the potential of acute toxicity via inhalation route of C12-13AS Na (CAS 1231880-35-5) 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. Due to its very low vapour pressure [2], inhalation is not viewed as a significant route of exposure. Inhalation of AS may occur via aerosols generated by spray cleaners or by detergent dusts (e.g. washing powder). Taking into account that the acute toxicity of AS is generally low but that the substance is irritating to skin and eyes at concentrations of 10% or higher, no additional information is expected from testing for acute inhalation toxicity as the predominant effect will be local irritation 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
Reliable OECD Guideline study was chosen.

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 toxicity meet the criteria for classification as Acute Tox Cat 4 (H302) according to Regulation (EC) 1272/2008 and as Xn (R22) according to Directive 67/548/EEC.

The available data on acute 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.