Docosan-1-ol

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2005

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Remarks:

The value was predicted using a validated QSAR.

Justification for type of information:

Please refer to attached justification documents

Qualifier:

no guideline required

Principles of method if other than guideline:

The result is not an experimental study but rather a calculation which follows the principles in the TGD guidance and which are presented in the publication Fisk et al. (2009).

GLP compliance:

no

Analytical monitoring:

not required

Vehicle:

not specified

Test organisms (species):

Daphnia magna

Test type:

other: calculated

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

as indicated by OECD guidance

Reference substance (positive control):

not required

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: QSAR

Remarks on result:

other: calculated EC50, QSAR, 48 h based on OECD guideline requirements

Predicted to be non-toxic at the limit of solubility.

Validity criteria fulfilled:

not applicable

Conclusions:

A reliable 48 h EC50 value of >100 mg/L has been calculated for the effects of the test substance towards Daphnia magna. Therefore the test substance has been predicted to be non toxic at the limit of solubility, so the EC50 is >0.1 mg/L (the solubility limit as described in section 4).

Description of key information

Short-term toxicity to invertebrates: EC₅₀ 48 h >100 mg/l (non-toxic at the limit of solubilty) (QSAR prediction) for the effects of docosan-1-ol on mobility of Daphnia magna.

Additional information

No experimental data are available for short-term toxicity of docosan-1-ol to invertebrates.

A 48 h EC₅₀ value of >100 mg/L has been calculated for the effects of the docosan-1-ol on invertebrates (Fisk et al., 2009). This result signifies that the test substance is expected to be non-toxic at the limit of solubility, i.e. the EC₅₀ is >0.001 mg/l.

Discussion of trends in the Category of C6-24 linear and essentially-linear aliphatic alcohols:

Single constituent LCAAs

The data show the toxicity of the linear LCAAs to increase from an EC₅₀ of 200 mg/L for C6 to 0.77 mg/L for C12. Effects have also been observed in tests with C13 and C14 LCAAs but at concentrations that exceeded the solubility of the alcohols. Although not explicitly identified in the test reports, physical effects (rather than true toxicity) cannot therefore be excluded from the interpretation of the results for these two LCAAs. In the Unilever (1994) study with C14 the authors have recorded that the test substance adhered to the daphnids at concentrations higher than the water solubility of 1-tetradecanol. This indicates that physical fouling is likely to have caused the effects seen at the EC₅₀ value of 4 mg/L.

 

Multi-constituents LCAAs

The data show the multi-constituent substances containing LCAAs with carbon numbers in the ranges of C7-9 to C12-15 to exert short-term toxicity at concentrations of between 0.23 and 30 mg/L. At these concentrations it is likely that all constituents will have been fully dissolved. The short-term EC₅₀ of the C14-15 LCAAs to aquatic invertebrate was determined to be above the limit of solubility of the substance.

For the C12-14 and C12-18 multi-constituent substances there was evidence of toxic effects in tests conducted on test media prepared as water-accommodated fractions at loading rates that exceeded the solubility of some constituents. For the C16-18 substance there was evidence of effects in test media that could have contained undissolved test material. The possibility of physical effects (rather than true toxicity) contributing to the observed effects were not discussed in the test report but cannot be excluded.

 

The data for nonanol, branched and linear, decanol branched and linear, decanol branched and undecanol branched and reaction mass of 2-methyldecan-1-ol and 2-propyloctan-1-ol and 2-ethylnonan-1-ol and 2-butylheptan-1-ol alcohols have been read-across from their linear LCAAs counterparts (C9, C10 and C11) since they are essentially linear LCAAs.

The measured data do not permit a definite toxicity cut-off to be identified for the single carbon number LCAAs or the multi-constituent substances. This is because the potential for physical effects to contribute to the results obtained for the C13 and 14 single carbon number alcohols, and the multi-constituent substances containing constituents with carbon numbers that are all >C12, cannot be excluded. However, it is reasonable to conclude from the data that are presented that it is unlikely that linear LCAAs with carbon numbers >C13 and multi-constituent LCAAs with carbon numbers all >C13 would be toxic.