Undecyl glucoside

Endpoint summary

Additional information

The Alkyl Polyglycosides Category contains D-Glucopyranose monomers and oligomers with fatty alcohols C4 to C18 linear or in several cases (C9 to C11) mono-branched. Structural similarities of the category substances are reflected in similar physico-chemical properties and mode of action. Alkyl polyglycosides have a common metabolic fate that involves hydrolysis of the α- and β-glycosidic bond to the fatty alcohol and glucose. Glucose and glucose oligomers enter the carbohydrate metabolic pathway and are catabolised into pyruvate and subsequently to the major extent into acetyl-CoA, which is introduced into the citric acid cycle with the aim to generate reduction equivalents for energy generation in the oxidative phosphorylation. Fatty alcohols, representing the main difference in the structure of different alkyl polyglycosides, are oxidized to the corresponding fatty acid and fed into the physiological pathway of β-oxidation, where they are also oxidised to acetyl-CoA. In addition to its function in the generation of energy by catabolic processes acetyl-CoA can also be used in anabolic processes like lipid synthesis which is important for the storage of energy in form of large high-energy macromolecules.

In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met. In particular for human toxicity, environmental fate and eco-toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across)”.

Therefore, the available experimental data were collected and evaluated according to Annex XI in regard to:

-             Test duration (only tests which cover the expected exposure duration were regarded as suitable)

-             Key parameters of the test (only tests that cover the key parameters were accepted as suitable)

-             Comparability of the test systems

-             The adequacy of the results for C&L

-             The documentation of the test procedures (only in case of good documentation data)

Only data that were judged to cover the requirements specified above were used as adequate data suitable for the category and its members.

In this particular case the similarity of the Alkyl Polyglycosides Category members is justified, in accordance with the specifications listed in Regulation (EC) No 1907/2006 Annex XI, 1.5 Grouping of substances and read across, on basis of scope of variability and overlapping of composition, representative molecular structure, physico-chemical properties, toxicological, ecotoxicological profiles, and supported by various QSAR methods. There is no convincing evidence that any one of these respective chemicals might lie out of the overall profile of this category. The key points that the members share are:

(i)             Common origin: produced from fatty alcohols, reacting with D-glucose in the presence of an acid catalyst.

(ii)            Similar structural features: aliphatic hydrocarbon chain bound to glucose oligomers by alpha or beta glycosidic bond.

(iii)           Similar physico-chemical properties: trend in log Pow based on alkyl chain length and degree of glycosylation; low vapour pressure; water solubility decreasing with the alkyl chain length, starting from very high and high values up to insoluble C16-18; surface active substances fully dissociated in water (exception: C16-18).

(iv)          Common properties for environmental fate & eco-toxicological profile: readily biodegradable, no potential for bioaccumulation, low to moderate adsorption potential, clear trend in aquatic toxicity (increasing toxicity with increasing carbon chain with a maximum at C12-16 and then decreasing), no potential for sediment and soil toxicity.

(v)           Similar metabolic pathways: absorption in the intestine, hydrolysis of the α- and β-glycosidic bond in intestine and further metabolism of the breakdown products sugar and alcohol. Alkyl polyglycosides with α-glycosidic bond may already be hydrolysed in the saliva by enzymatic activity of α-amylases.

(vi)         Common levels and mode of human health related effects: The skin and eye irritating properties of the alkyl polyglycosides represent the main factor for effects on human health. The similar toxicokinetic behaviour (hydrolysis of the α- and β-glycosidic bonds) results in similar cleavage products, which show a low toxicity after acute and repeated oral exposure. Furthermore, all category members are not sensitising, not mutagenic or clastogenic, and have shown no reproduction and developmental toxicity.

Similar ecotoxicity profile

Many studies are available on the short- and long-term toxicity to fish, invertebrates, algae, microorganisms, sediment and terrestrial organisms within the category of alkyl polyglycosides (see also experimental data presented in Table 6). The results available on the toxicity to fish, invertebrates and algae demonstrate, that toxicity across the trophic levels within the aquatic compartment is rather similar. The most important influencing parameter for aquatic toxicity within the alkyl polyglycosides category is the chain length of the alkyl group. The carbon chains with lengths of C12-16 caused low effects to aquatic organisms whereas the chains below and above C12-16 were less or even non-toxic.

Sediment is not expected to be a compartment of concern since alkyl polyglycosides are mostly well soluble in water (except for D-Glucose, reaction products with alcohols C16-18 (even numbered) (excess)), have a low potential for bioaccumulation and are readily biodegradable. Therefore, alkyl polyglycosides will be eliminated in standard treatment plants. In case of release to sediment, the substances are expected to rapidly degrade in the environment. Furthermore, studies on sediment toxicity are available for most of the category members. Again, a trend of increasing toxicity with increasing carbon chain length could be observed. Nevertheless, effects occurred only at very high concentrations (LC50 values range from 650.45 mg/kg dw to > 7023.1 mg/kg dw and NOEC values range from 71.36 mg/kg dw to 698 mg/kg dw).

In case of exposure to soil, the substances are also expected to rapidly degrade, thus the hazard to terrestrial organisms is assumed to be negligible. Additionally, some studies on terrestrial macroorganisms (D-Glucopyranose, oligomeric, butyl glycoside; D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)) and terrestrial plants (D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)) consistently show no effects on the test organisms.

Aquatic toxicity

Short-term fish toxicity

Short-term toxicity to fish is well studied for the category of alkyl polyglycosides and includes studies with substances ranging from D-Glucopyranose, oligomeric, butyl glycoside to D-Glucose, reaction products with alcohols C16-18 (even numbered) (excess), covering a variety of both freshwater and marine species. Alkyl polyglycosides of chain lengths from C4 to C8-10 seem to have low to moderate toxicity, whereas substances from C9-11 to C10-16 are more toxic. Toxicity of D-Glucose, reaction products with alcohols C16-18 (even numbered) (excess) could not be observed, which can be explained by reduced bioavailability as a consequence of the low water solubility.

The 96-hour LC50 values for fish determined for alkyl polyglycosides vary from 2.95 mg/L for D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9) up to 420 mg/L for D-Glucopyranose, oligomers, hexyl glycosides.

Short-term toxicity to aquatic invertebrates

The influence of the chain length of alkyl polyglycosides on the acute invertebrate toxicity is comparable to that on fish toxicity. Also in this case a clear correlation can be shown between the toxicity of alkyl polyglycosides and the carbon chain length; the available experimental database includes studies on alkyl polyglycosides ranging fromD-Glucopyranose, oligomeric, butyl glycoside to D-Glucose, reaction products with alcohols C16-18 (even numbered) (excess). Short-term toxicity to aquatic invertebrates increases with increasing length of the hydrocarbon chain up to C16 and then decreases.

The 48-h EC50 values for aquatic invertebrates determined for alkyl polyglycosides range from 7 mg/L forD-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9) to 3160 mg/L forD-Glucose, reaction products with alcohols C16-18 (even numbered) (excess), based on the results of key studies.

Long-term fish toxicity

One long-term test on fish is available for D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9), with a resulted NOEC value of 1.8 mg/L. As D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9) represents the worst case regarding acute aquatic toxicity, this study is applied as source for read-across for the other members of the alkyl polyglycosides category.

Long-term toxicity to aquatic invertebrates

One long-term test on aquatic invertebrates is available for the member substance D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9), with a resulting EC10 value of 1.76 mg/L. As D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9) represents the worst case regarding acute aquatic toxicity, this study is applied as source for read-across for the other members of the alkyl polyglycosides category.

Furthermore, a study is available for octadecanol (CAS 112-92-5), representing a main component of D-Glucose, reaction products with alcohols C16-18 (even numbered) (excess). As a result, a NOEC (21 d) value of 0.98 mg/L was stated (mortality and reproduction). However, considering the low solubility of the substance (<1 mg/L), the resulted NOEC might lie above the water solubility and could reflect the effects of physical fouling rather than true toxicity of the tested substance.

Toxicity to aquatic algae

Several reliable experimental studies with algae are available for alkyl polyglycosides. The influence of the chain length on the toxicity to algae is comparable to that on fish and invertebrate toxicity. Also in this case a clear correlation can be shown between the toxicity of alkyl polyglycosides and the carbon chain length; the available experimental database includes studies on alkyl polyglycosides ranging from D-Glucopyranose, oligomeric, butyl glycoside to D-Glucose, reaction products with alcohols C16-18 (even numbered) (excess). Short-term toxicity to algae increases with increasing length of the hydrocarbon chain up to C16 and then decreases.

The 72-h EC50 values for freshwater algae determined for alkyl polyglycosides range from 12.5 mg/L for D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9) to 780 mg/L for D-Glucopyranose, oligomers, hexyl glycosides. An EC50 (72 h) of 8.4 mg/L Reaction products of D-Glucose, n-Butanol and alcohols C10-12 (even numbered) was determined in the key study for marine algae. The 72-h NOEC values for algae range from 2 mg/L for D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9) to 125 mg/L for D-Glucopyranose, oligomers, hexyl glycosides,based on key studies.

Toxicity to microorganisms

Activated sludge respiration inhibition tests and Pseudomonas putida tests are available for the alkyl polyglycosides of chain lengths from D-Glucopyranose, oligomeric, butyl glycoside to D-Glucose, reaction products with alcohols C16-18 (even numbered) (excess). No effects were observed for all of the substances across the category, and results range from 6 h EC50 > 560 mg/L to 16 h EC0 = 5000 mg/L.

Sediment Toxicity

All alkyl polyglycosides are well soluble in water (except for D-Glucose, reaction products with alcohols C16-18 (even numbered) (excess)), have a low potential for bioaccumulation and are readily biodegradable, therefore they will degrade in the STP process. In case of release to sediment, the substances are expected to rapidly degrade in the environment. Therefore, sediment is not expected to be a compartment of concern for the majority of the category members.

Additionally, studies are available for most of the category members (D-Glucopyranose, oligomers, undecyl glycosides; D-Glucopyranose, oligomers, hexyl glycosides; D-Glucopyranose, oligomers, decyl octyl glycosides (CAS 68515-73-1); D-Glucopyranose, oligomers, branched and linear C9-11-alkyl glycosides (CAS 157707-87-4); Reaction products of D-Glucose, n-Butanol and alcohols C10-12 (even numbered); D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)). Results from these studies range from an LC50 of 650.45 mg/kg dw to > 7023.1 mg/kg dw and NOEC values from 71.36 mg/kg dw to 698 mg/kg dw. Again, a trend of increasing toxicity with increasing carbon chain length could be observed.

Long-term data do not have to be generated because of the low to moderate log Koc values and the ready biodegradability of the test substances.

Terrestrial toxicity

Toxicity to terrestrial organisms is expected to be low. All alkyl polyglycosides exhibit an adsorption coefficient (log Koc) below 4 (except for D-Glucose, reaction products with alcohols C16-18 (even numbered) (excess)) and are readily biodegradable. Hence, persistency in soil is not expected. Moreover, the substances are acutely not toxic in the aquatic compartment (EC/LC50 for fish, aquatic invertebrates and algae > 1 mg/L; according to ECHA Guidance on information requirements and chemical safety assessment, Chapter R.7c: Endpoint specific guidance). In case of exposure to soil, the substances are expected to rapidly degrade, thus the hazard to terrestrial organisms is negligible.

Additionally, studies on earthworms and terrestrial plants are available for D-Glucopyranose, oligomeric, butyl glycoside and D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9) and showed no toxic effects. No effects were observed up to 1000 mg/kg dw D-Glucopyranose, oligomeric, butyl glycoside and up to 654 mg/kg D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9) in tests with Eisenia sp. (OECD 222 and 207, respectively), and up to 654 mg/kg D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9) in tests with terrestrial plants (OECD 208).

Table 1: Environmental Toxicity (*)

ID No.

Substance

CAS No.

Short term toxicity to fish 96h LC50

Long term toxicity to fish

Short term toxicity to aquatic invertebrates 48h EC50

Long term toxicity to aquatic invertebrates

Toxicity to aquatic algae

Toxicity to microorganisms

Sediment Toxicity

Terrestrial Toxicity

# 1

D-Glucopyranose, oligomeric, butyl glycoside

-

ER: LC50 > 51 mg/L, no effects in limit test

Data waiving

ER: EC50 > 51 mg/L, no effects in limit test

Data waiving

ER: 72h ErC50 >51 mg/L, NOECr ≥51 mg/L, no effects in limit test

Data waiving

--

ER: 56d NOEC earthworms ≥ 1000 mg/kg bw

# 2

D-Glucopyranose, oligomers, hexyl glycosides

-

ER: 420 mg/L

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: 490 mg/L

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: 72h ErC50 = 780 mg/L, NOECr = 125 mg/L

ER: 4h EC50 >1000 mg/L

ER: LC50 > 1547 mg/kg sediment dw

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

# 3

D-Glucopyranose, oligomeric, heptyl glycoside

1627851-18-6

RA from D-Glucopyranose, oligomers, decyl octyl glycosides (CAS 68515-73-1)

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: >100 mg/L

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: 72h ErC50 > 150 mg/L, NOECr = 44.5 mg/L

Data waiving

ER: LC50 (10 d) = 3318.81 mg a.i./kg dw

RA from D-Glucopyranose, oligomeric, butyl glycosides

# 4

D-Glucopyranose, oligomers, undecyl glycosides

-

ER: LL50 >37.6 mg/L

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: LL50 = 60.19 mg/L

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: ErL50 = 37.5 mg/L; NOELrR = 10 mg/L

--

ER: LC50 (10 d) = 901.92 mg/kg dw

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

# 5

D-Glucopyranose, oligomers, decyl octyl glycosides

68515-73-1

ER: 100 mg/L, marine 96.6 mg/L

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER:  >100 mg/L, marine 31.6 mg/L

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: 72h ErC50 27.2 mg/L (key study), marine (based on supp. studies): ErL50 = 7 mg/L,NOECr = 6 mg/L

ER: 6h EC50 > 560 mg/L

ER: LC50 (10 d) > 433.61 mg/kg dw

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

# 6

D-Glucopyranose, oligomers, branched and linear C9-11-alkyl glycosides

157707-87-4

ER: marine LL50 ≥0.5 mg/L (limit test), RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9): 2.95 mg/L

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: 26.2 mg/L

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: 72h ErL50 = 9.05 mg/L, NOErLR = 5 mg/L

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: LC50 (14 d) = 3732.74 mg a.i./kg dw

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

# 7

Reaction products of D-Glucose, n-Butanol and alcohols C10-12 (even numbered)

-

ER: 129 mg/L, marine 78.4 mg/L

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: marine 19.95 mg/L

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: marine 72h ErC50 = 8.4 mg/L, NOECr = 3.5 mg/L

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: LC50 (10 d) > 7023.1 mg a.i./kg dw

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

# 8

D-Glucopyranose, oligomeric, C10-16-alkyl glycosides

110615-47-9

ER: 2.95 mg/L, marine (based on supp. studies): 4.4 mg/L

ER: NOEC = 1.8 mg/L

ER: 7 mg/L, marine (based on supp. studies) 4.33 mg/L

ER: EC10 = 1.76 mg/L

ER: 72h ErC50 = 12.5 mg/L, NOECr = 2 mg/L, marine (based on supp. studies): EL50 = 1.17 mg/L, NOEC = 1.8 mg/L

ER: 16h EC0 = 5000 mg/L

ER: LC50 (10 d) = 650.45 mg a.i./kg dw

ER: 14d EC50 earthworms, plants >654 mg/kg dw

# 9

D-Glucose, reaction products with alcohols C16-18 (even numbered) (excess)

-

ER: >10,000 mg/L (no effects up to WS limit)

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: 3160 mg/L (no effects up to WS limit)

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

ER: 72h ErC50 = 28 mg/L, ECr10 = 21.7 mg/L (no effects up to WS limit)

ER: 30 min EC10 >10,000 mg/L (no effects up to WS limit)

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

RA from D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9)

# 10

Hexadecan-1-ol (a)

36653-82-4

ER: >0.4 mg/L (no effects up to WS limit)

--

--

--

ER: EL50 690 mg/L (no effects up to WS limit); EL10

--

--

--

# 11

Octadecan-1-ol (a)

112-92-5

ER: >0.4 mg/L (no effects up to WS limit)

--

ER: 1700 mg/L (no effects up to WS limit)

ER: NOEC 0.98 mg/L (no effects up to WS limit)

ER: EL50 0.64 - 10 mg/L (no effects up to WS limit); EL10

--

--

--

(*) substances #2, #5 and #8 were registered in 2010, substances #1, #6, #7 and #9 (bold font) were registered in 2013; substance #3 and #4 (bold italics font) are registered or scheduled for registration under Regulation (EC) No 1907/2006 (REACH) in 2014-2016.

(a)Surrogate substances: fatty alcohols. Available data on these substances are used for assessment of ecotoxicological properties by read-across on the basis of structural similarity and/or mechanistic reasoning. They are no members of the Alkyl Polyglycosides Category.

Several studies on the short-term aquatic toxicity to fish are available for D-Glucopyranose, oligomeric, undecyl glycoside. The most reliable study resulted in an LL50 of > 37.6 mg/L. Assessment of long term toxicity to fish relies on a read-across to the category member D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9) and a NOEC of 1.8 mg a.i./L was determined. D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9) represents the worst case scenario within the category members in terms of aquatic toxicity. Concerning short-term toxicity of D-Glucopyranose, oligomeric, undecyl glycoside to aquatic invertebrates, an LL50 of 60.19 mg/L was determined by the most reliable study. Long-term toxicity to aquatic invertebrates was covered with a read-across from the structurally related category substance D-Glucopyranose, oligomeric, C10-16-alkyl glycosides (CAS 110615-47-9). The NOEC determined in this study was 1.76 mg a.i./L. Three studies for D-Glucopyranose, oligomeric, undecyl glycoside are available evaluating its toxicity to algae. The key study resulted in an ErL50 of 37.5 mg/L and a NOErLR of 10 mg/L.

Based on this data an assessment is possible and aquatic toxicity is assumed to be low.

The substance can be assumed to be not inhibitory to aerobic activated sludge microorganisms due to the results of the toxicity control in the ready biodegradation test.