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Description of key information

For the whole category of alcohol ethoxysulfates (AES) a oral NOAEL of 300 mg/kg bw/d was established.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEL
300 mg/kg bw/day
Study duration:
subchronic
Species:
rat
Quality of whole database:
The whole data base is conclusive and of high quality.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
195 mg/kg bw/day
Study duration:
subchronic
Species:
mouse
Quality of whole database:
The dose levels of the dermal study were chosen to produce irritating effects. Therefore, with regard to the systemic toxicity of the AES the doses are low. In conclusion the NOAELs from the repeated oral toxicity studies were considered for the risk assessment.

Repeated dose toxicity: dermal - local effects

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEL
397 µg/cm²
Study duration:
subchronic
Species:
rat
Quality of whole database:
The whole data base is conclusive and of high quality.

Additional information

Data on repeated dose toxicity are available for AES (C12-14; 2EO) Na (CAS 68891-38-3), AES (C10-16; 3 EO) Na (CAS 68585-34-2), and lauryl(3EO)ethoxysulphate. These data are also used to cover this endpoint for the other AES within the AES-category, i.e. AES (C9-11) Na (CAS 160901-27-9), AES (C8-10) NH4 (CAS 68891-29-2), AES (C12-14) NH4 (CAS 125301-88-4), AES (C12-14) MIPA (EC 932-185-7), AES (C12-14) Mg (CAS 160104-51-8), AES (C10-16) Mg (CAS 67762-21-4), AES (C8-10) Na, AES (C9-11) Na (CAS 160901-28-0), AES (C10-12) Na (CAS 68610-66-2), AES (C12-13) Na (CAS161074-79-9), AES (C12-14) Na (CAS 68891-38-3), AES (C12-18) Na (CAS 68081-91-4).

The AES reported within the category show similar structural, physico-chemical, environmental and toxicological properties. The approach of grouping different AES for the evaluation of their effects on human health and the environment was also made by the Danish EPA [1] and HERA [2], supporting the read-across approach between structurally related AES.

In a subchronic oral gavage study according to OECD Guideline 408, AES (C12-14) Na (CAS 68891-38-3, no data on grade of ethoxylation) was tested for systemic toxicity at doses of 0, 25, 75, 225 mg/kg bw/day on Wistar rats (Pittermann, 1994). No clinical signs of toxicity, no mortalities and no effects on any other investigated parameter (body weight, body weight gain, food consumption, water consumption, ophthalmoscopic examinations, haematology, clinical chemistry, organ weights, gross pathology and histopathology) were seen at the highest dose level. Apart from the missing systemic toxicity, local treatment-related concentration-dependent irritation to different degrees in the forestomach was seen in all test groups. Thus, a NOEL-value was not determined. Since there is no human equivalent to the rat forestomach, these effects are not considered to be relevant to human health assessment. Thus, a no adverse effect level (NOAEL) of greater than 225 mg/kg could be established.

In another subchronic feeding study four groups of 20 rats per sex were fed 0, 0.05, 0.5 and 5.0% (w/w) of the AES (C10-16; 3 EO) Na (CAS 68585-34-2) over a period of 91 days (Ashby, 1977). The test material contained 30% active ingredient, converting the doses to 0, 10, 100 and 1100 mg/kg bw/day active substance. There were no observable differences in the appearance, mood, locomotion, and fecal consistency of treated and control animals and no animals died during the treatment period. No statistically significant changes in food consumption occurred during the study. The body weight gains of both sexes in the 5.0% group were reduced from the commencement of treatment, so that their body weights were significantly different from the controls when analyzed at Week 2, at termination their body weights were 84% (males) and 85% (females) of those of the respective controls. The body weight gains of both sexes in the 0.5% group were lower from Week 5 (males) or 6 (females), although this reduction was statistically significant in the males only. The food conversion ratio of males in the 5.0% group was consistently reduced, indicating inferior food utilization; however, it is not specified if this finding was statistically significant. Females in the 5.0% group displayed erythrocytic characteristics slightly lower than in the controls, with statistically significant effects on packed cell volume and erythrocyte count. Serum glutamate pyruvate transaminase and alkaline phosphatase levels were significantly elevated in both sexes in the 5.0% group. The liver weights of both sexes in the 5.0% group were significantly elevated. The heart weights of both sexes in the 5.0% group were significantly reduced when analyzed in absolute terms and relative to brain weight. No treatment-related changes were seen in the macroscopic appearance of the tissues examined at necropsy. No histopathological changes or variations that were considered treatment-related were observed in any of the tissues and organs examined. Several effects were seen in the lungs, liver and kidneys; however, they were not statistically significant and were considered not to be of toxicological significance. There were no treatment-related effects on the organ weights (both absolute and relative), or macroscopic or microscopic pathology of the gonadal tissues examined. Since the decrease in the erythrocyte count was not dose-dependent, it was concluded that the test substance at dietary levels up to 0.05% test material (corresponding to 100 mg/kg bw/day) elicited no adverse effects.

A third subchronic study was designed to evaluate the toxicological effects of AES (C10-16; 3 EO) Na (CAS 68585-34-2) in albino rats (20/sex/group) when administered in the diet for thirteen weeks at levels of 0.0, 0.1, 0.5, and 1.0% active ingredient (corresponding to 0, 60, 300 and 600 mg/kg bw/day) (Picrillo, 1977). Interim sacrifices were performed on five rats/sex/group at four weeks and ten rats/sex/group at thirteen weeks. Five rats/sex/group were maintained on study for one additional week and sacrificed at Week 14. The criteria evaluated for compound effects were clinical signs, mortality, body weight and food consumption, ophthalmoscopic findings, clinical chemistry and haematology, organ weights, and gross and microscopic pathology. No distinct effect attributed to the administration of the test substance were noted in comparisons of the clinical signs, mortality rates, ophthalmoscopic findings or haematology and blood chemistry values of the test groups to the controls. In addition, no compound related gross or histomorphologic organ or tissue alterations were noted in any of the treated animals. When compared to the data of the control group, slightly lower body weight gains were noted in the mid- and high-dose male groups. These differences were not statistically significant. The absolute and relative liver weights of all treated groups of both sexes were slightly, to moderately higher than respective control data at Weeks 4, 13 and 14. These differences were generally (but not always distinctly) dose-related and statistically significant at some of the intervals. The heart weights and ratios of all of the male treated groups were slightly (not statistically significantly) lower than those of the controls at Weeks 4, 13 and 14. However, neither gross pathology, nor microscopic examination of liver and heart sections confirmed the presence of any treatment-related hepatic or cardiac alterations. Gonadal tissues were examined for both gross pathology and histopathology and no treatment-related effects were detected. No outstanding treatment related toxic effects were noted when the test substance was administrated up to 600 mg/kg bw/day in the diet to albino rats. Although there were statistically significant differences in absolute and relative liver and heart weights noted in test substance-treated groups compared to control animals, and these differences were generally dose-related, no histopathological correlation was found to confirm the presence of any treatment-related alterations. As such the NOEL was determined to be 600 mg/kg bw/day.

Synthetic AES (C12-15; 3 EO) Na and natural AES (C12; 3 EO) Na (sodium lauryl(3EO)ethoxysulphate) were tested in a 90-day rat diet study at dose levels of 0, 40, 200, 1000 and 5000 ppm active material, corresponding to 0, 2, 10, 50 and 250 mg/kg bw/day (Walker, 1967). Health, behaviour, body weight, food intake, haematological and urinary parameters remained within normal limits at all doses. In both studies organ weight and blood chemistry effects observed were unaccompanied by any pathological changes. Based on the available information and taking into account that the study was conducted prior to the development of GLP and OECD guidelines, a NOAEL could be established at the dose level of greater than 250 mg/kg bw/day.

 

Further information on subchronic toxicity can be deduced from a two-generation reproduction study with AES (C12-14, no data on grade of ethoxylation) Na (CAS 68891-38-3) (Biggs, 1999). Sprague Dawley rats were dosed via the drinking water at the concentrations 0, 0.03, 0.1 and 0.3%, which corresponded to daily doses of ca. 0, 30, 100 and 300 mg/kg bw. There were some changes indicative of parental toxicity in the group treated with 0.3% of the test substance.

Slight but significantly reduced straight line velocity (VSL) of the sperm was without any significant effects on averaged path velocity (VAP) or total motility. Moreover, in the available subchronic and chronic toxicity studies on various AES the primary sex organs of the males and females did not show evidence for treatment-related adverse effects. The observed reduced triglyceride levels (female) and increased percentage neutrophil counts (males) were slight and within the range of the historical control data.

The male F0 generation showed a small but significant reduction in body weight-liver weight ratios, but the corresponding brain related liver weights and the absolute liver weights developed not in a dose dependant way. For the F1 generation where similar results were reported, no dose-response relationship was detected either. No influence on liver weight development was seen in the F2 generation. None of the groups revealed any histopathological or clinical-chemical findings, which could be attributed to hepatotoxicity. This led to the conclusion that this untypical liver weight reduction was of no toxicological relevance, additionally underlined by the absence of such effects in the studies for subchronic toxicity mentioned above.

There was evidence of toxicity on pup development at this dose level that was characterised by an increase in the time taken for sexual development of the male (not significant) and female (significant) offspring. This was investigated in more detail in the developmental toxicity studies up to 1500 mg/kg bw and no effects were noted there. Considering all these facts the subchronic NOAEL for systemic toxicity can be set to greater than 300 mg/kg bw.

No unusual findings regarding systemic toxicity were noted in a 2-year chronic feeding study in rats in which AES (C12; 3EO) (lauryl(3EO)ethoxysulphate) was given at 0, 0.1 or 0.5% (corresponding to 0, 50, 250 mg/kg bw/day) in the diet (Little, 1991). The results of this study suggest that the NOEL for AES (C12; 3EO) in this 2-year chronic feeding study in rats was greater than 250 mg/kg bw. In another 2-year study (Little, 1991), rats were administered AES (C12; 3 EO) (lauryl(3EO)ethoxysulphate) in the drinking water at a concentration of 0.1% (equals a dose of 75 mg/kg bw/day). The only unusual finding was slight, but consistently higher water consumption by all rats receiving the test compound in their drinking water and a significant difference in the empty caecum to body weight ratio of females. Absolute organ weights were all comparable to controls and no consistent gross or histopathology was found. A NOEL greater than 75 mg/kg bw can be estimated on the basis of the available information.

 

There are also two repeated dose toxicity studies with dermal application available.

The objective of the first study (Cardin, 1978) was to determine the histopathological effects on the skin at treatment sites after repeated dermal exposure to AES (C10-16; 3 EO) Na (CAS 68585-34-2) over 91 days with a 28 day interim sacrifice. 25 ICR-Swiss CD-1 mice per sex and group were assigned to each of the following treatment groups. The dose volume for each group was 0.1 mL with the control group being sterile water, a 2.38 mg/day test group, and a 6.91 mg/day test group. An area of 2 x 3 cm of the dorsal area of all animals was clipped and treated with the appropriate dose five times per week. All animals were observed daily for signs of general health, mortality and gross skin irritation effects. Gross signs of toxicity and body weights were recorded on a weekly basis throughout the study. After 28 days (21 dermal applications) ten animals per sex from each group were sacrificed and necropsied. The remaining animals continued on the treatment regimen until the termination of the study. At study termination (90-92 days from initiation of the study), five females from each group were sent to the sponsor for in-vitro skin penetration studies.The remainder of the animals were sacrificed and necropsied.

No mortalities were attributed to treatment and there were no significant differences in body weights in any animals throughout the study. Gross necropsies at interim or terminal sacrifice did not reveal any compound related lesions with the exception of skin effects at the site of treatment. At the 28 day interim evaluation, repeated dermal applications in both test groups did not result in any gross skin effects with exception of two animals per group, which exhibited scaling and erythema or scales in the dorsal area which were not deemed to be of significance. Histopathological examinations of the skin exhibited comparable skin effects as controls. Furthermore, animals treated with 2.38 mg/day of the test substance did not exhibit any gross or microscopic compound related irritative effects after 91 days of treatment. However, mice treated with 6.91 mg/day of the test substance showed minimal or slight acanthosis in 12 of the 25 mice. Gonadal tissues were examined for both gross pathology and histopathology and no treatment-related effects were detected.

The test substance did not produce dermal irritation after 91 days of treatment at a dose of 2.38 mg/day. When calculating the concentrations based on mg/cm2 the NOAEL for local effects was 0.4 mg/cm2. Increasing the dose to 6.91 mg/day (corresponds to 1.15 mg/cm2) over 91 days did induce some irritation effects. No systemic effects were identified at either dose level. Thus, the systemic NOEL was the highest dose of 195 mg/kg bw/d.

 

In the second subchronic percutaneous toxicity study (Ligntowler, 1976) with AES (C10-16; 3 EO) Na (CAS 68585-34-2), three New Zealand White rabbits per sex were exposed to 0.9% active ingredient (corresponding to 18 mg/kg bw/day) to the intact non-occluded skin of the back over 13 weeks. The animals treated with the test substance developed a low grade erythematous reaction at the site of topical application which persisted at the same intensity for the last nine weeks of the study. Weight-gain, haematology, blood chemistry, liver and kidney weights, macropathology and micropathology displayed no evidence of a systemic reaction to treatment. It was concluded that repeated topical application provoked only a mild erythema at the site of application without inducing a systemic reaction.

 

 

Since the dose levels from the repeated dermal toxicity studies were very low and did not produce any systemic signs, only the NOAELs from the repeated oral toxicity studies were considered for the risk assessment. The respective NOAELs and LOAELs are listed in Table 1. 

 

Table 1: Dietary NOAELs and LOAELs (a.i.) for repeated oral toxicity studies of AES

Substance

Duration

(weeks)

NOAEL/NOEL

(mg/kg bw/day)

LOAEL

(mg/kg bw/day)

Reference

AES(C12-14)Na

13

225

> 225

Pittermann (1994)

AES(C12-15;3EO)Na

AES(C12;3EO)Na

13

250

> 250

Walker (1967)

AES(C10-16;3EO)Na

13

100

1100

Ashby (1977)

AES(C10-16;3EO)Na

13

600

> 600

Piccirillo (1977)

AES(C12-14)Na

13

300

> 300

Biggs (1999)

AES(C12;3EO)

104

250

> 250

Little (1991)

 

No LOAELs could be detected in the most studies, except for one study were a LOAEL was established at 1100 mg/kg bw/d (Ashby, 1977). However the dose tested exceeded the next lower dose within this study by 11 times. In addition the LOAEL is almost twice of the highest reported NOAEL. With exception of this study all NOAELs represented the highest dose level. Therefore an average of all NOAEL was chosen as basis for the risk assessment.

The available oral toxicity studies provide a coherent picture on the subchronic and chronic oral toxicity of AES. Based on the described effects, the NOAEL of 300 mg/kg bw/day (Biggs, 1999) representing an average of all NOAELs, was chosen for the risk assessment.

 

 

[1] Danish EPA, Environmental Project No. 615, (2001);
http://www2.mst.dk/udgiv/publications/2001/87-7944-596-9/pdf/87-7944-597-7.pdf

[2] (HERA report, 2003);
http://www.heraproject.com/files/1-HH-04-HERA%20AES%20HH%20web%20wd.pdf


Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
One of the reliable OECD guideline studies reflecting the low toxicity was chosen.

Justification for selection of repeated dose toxicity dermal - systemic effects endpoint:
Scientifically reliable study.

Justification for selection of repeated dose toxicity dermal - local effects endpoint:
Scientifically reliable study.

Justification for classification or non-classification

The available data on repeated dose 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.