Sodium decyl sulphate

Endpoint summary

Description of key information

Oral LD50 (OECD guideline 401), rat = 1200 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:

1 200 mg/kg bw

Quality of whole database:

The whole data base is reliable and of high quality.

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Quality of whole database:

Acute toxicity by inhalation was not tested according to REGULATION (EC) No 1907/2006, Annex VIII, Section 8.5, Column 2.

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 reliable and of high quality.

Additional information

There is one study for the acute oral toxicity of C10AS Na (CAS 142-87-0) available. However this study is deemed to be not reliable (for details see below). Therefore the endpoint acute toxicity is covered by read across to structurally related alkyl sulfates, i.e. C8AS Na (CAS 142-31-4) and C12AS Na (CAS 151-21-3) 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. 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 available study with C10AS Na (CAS 142-87-0, analytical purity 29-30%) addressing acute oral toxicity was conducted similar to OECD Guideline 401 on Sprague-Dawley rats (Potokar, 1985). Animals of both sexes were dosed with the test substance at 1000 and 2000 mg/kg bw via gavage. 5 animals per sex were dosed with 2000 mg/kg bw but only 2 animals per sex were dosed with 1000 mg/kg bw. Clinical signs of toxicity comprised of piloerection, diarrhoea and abdominal position in females at 1000 mg/kg bw and piloerection, paleness, bloody urine and cramps at 2000 mg/kg bw. Upon necropsy anaemia of internal organs, inflammation/haemorrhages in the GI tract and peritonitis were observed at the high dosed animals. Mortalities within the dose groups were: 0/2 males and 1/2 females at the low dose and 3/5 males and 4/5 for females at the high dose. Only limited information on the test item is available within the study report. The test item used is a formulation which is expected to have a higher pH value (>11.5) than pure C10AS Na (CAS 142-87-0). No information about a possible alkaline adjustment of the test substance is given. Therefore it cannot be excluded that the test item had a considerably higher pH value than the reference substance would have. This assumption is supported by the effects seen in the GI tract upon necropsy. As this methodological deficiency cannot be excluded the study is not reliable for risk assessment and the study was judged to be not reliable (RL3).

The endpoint acute oral toxicity is therefore covered by read across to C8AS Na (CAS 142-31-4) and C12AS Na (CAS 151-21-3).

The study conducted with C12AS Na (CAS 151-21-3) was performed according to OECD Guideline 401 with acceptable restrictions on Wistar rats (Potokar, 1983). Both sexes were dosed with the test substance via gavage. Mortalities occurred but no details were available. Clinical signs of toxicity comprised of diarrhoea, spastic gait, decreased activity, lateral position, hunched posture, laboured respiration and coma. Necropsy of dead animals revealed haemorrhages in gastro-intestinal tract and vascular congestion in the liver. No findings were observed in animals sacrificed upon study termination. The LD50 was given as 1200 mg/kg bw for males and females, 977 mg/kg bw for females and 1427 mg/kg for males.

The second study conducted with C12AS Na (CAS 151-21-3, analytical purity 30%) was performed similar to OECD Guideline 401 (Esposito, 1976). 5 Wistar rats of each sex were dosed with the test substance at the limit dose of 5000 mg/kg bw via gavage and observed for mortalities and behaviour for 14 days. Mortalities occurred 24 hours (2/5 males) and 3 days after treatment (1/5 females). No depression of animals was observed during the post exposure period. The LD50 was determined to be greater than 5000 mg/kg bw based on the test substance and greater than 1500 mg/kg bw based on the active ingredient.

The study conducted with C8AS Na (CAS 142-31-4) was performed according to OECD Guideline 423 with Wistar rats (BASF, 2012). Two groups of three female rats were treated with 2000 mg/kg bw via gavage according to the Acute Toxic Class method. The observation period was 14 days. One animal was found dead 5 h after administration in application group 1. No mortality occurred in the second test group. Clinical signs of toxicity comprised impaired general state, dyspnoea and piloerection. All animals gained weight throughout the whole study period. Upon pathology no findings were observed in the surviving animals of both groups.

Thus, the LD50 of 1200 mg/kg bw observed for males and females by Potokar (1983) was chosen as LD50 for C10AS Na (CAS 142-87-0) as a conservative approach.

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. 5 Wistar rats per sex were treated with 2000 mg/kg bw under semi occlusive conditions for 24 h (BASF, 2012). 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, 1975). 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 conducted similar to OECD Guideline 402 with 3 male and 3 female New Zealand White rabbits (Frank, 1975). 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.

Within the studies mentioned above no mortalities 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. Moreover, the used final product is a dilution of substance (20 - 30%) and does not contain the neat alkyl sulfate. In agreement, no classification for acute dermal toxicity is required. For details on absorption please see section Toxicokinetics, metabolism and distribution.

Acute inhalation toxicity 

No studies for acute inhalation toxicity are available. However, testing the potential of acute toxicity via inhalation route of C10AS Na (CAS 142-87-0) 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. However, as the neat substance has to be classified as harmful if swallowed the substance will also be classified as harmful if inhaled (H332: Acute tox 4 and R20, respectively) in case the substance is available as neat powder.

 

[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
The study in which the LD50 was achieved was selected.

Justification for selection of acute toxicity – dermal endpoint
Reliable OECD guideline 402 study.

Justification for classification or non-classification

The available data on acute oral toxicity meet the criteria for classification as Acute Toxic Category 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.