1,2-Heptanediol

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 29-Apr-2011 to 20-Jul-2011

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

For measurement of the actual concentrations of the test item, quadruplicate samples were taken from the test media of all test concentrations and the control at the start of the test (without algae) and at the end of the test (containing algae).
For the 72-hour stability samples, additional flasks containing the test medium with algae were incubated for each treatment under the test conditions. This was necessary since the volume of test solution of the treatment replicates (3 x 15 mL) was too small to perform the analyses.
All samples were stored deep-frozen (at about -20 °C) immediately after sampling until analysis. In pre-experiments (non-GLP), the test item proved to be stable under these storage conditions.
The concentration of the test item was determined in two of the quadruplicate test medium samples from the highest nominal test concentration of 100 mg/L. The samples from the lower test concentrations were not analyzed, since these concentrations were below the NOEC determined in this test and were not relevant for the interpretation of the biological results. From the control samples, one of the quadruplicate samples was analyzed per sampling time.

Vehicle:

no

Details on test solutions:

The test medium of the highest nominal concentration of 100 mg/L was prepared by dissolving 200.7 mg of the test item completely in 2000 mL of test water using ultrasonic treatment for 5 minutes and intense stirring for 10 minutes at room temperature. This test medium was serially diluted with test water to prepare the test media of the lower test concentrations. The test media were prepared just before the start of the test.

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

The test organism used for the study was Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum), Strain No. 61.81 SAG, supplied by the Collection of Algal Cultures (SAG, Institute for Plant Physiology, University of Göttingen, 37073 Göttingen / Germany). The algae were cultivated at Harlan Laboratories under standardized conditions according to the test guidelines.
An inoculum culture was set up three days before the start of the exposure. The algae were cultivated under the test conditions and were kept in the exponential growth phase until inoculation of the test solutions.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

no data

Hardness:

24 mg/L as CaCO3

Test temperature:

The water temperature during the test was maintained at 21 °C.

pH:

At the start of the test, the pH measured in the treatments was between 8.1 and 8.2. At the end of the test, pH values of 8.7 to 8.8 were measured.

Dissolved oxygen:

no data

Salinity:

no data

Nominal and measured concentrations:

nominal: 1.0, 3.2, 10, 32 and 100 mg/L
The measured concentration of the test item in the test medium of the highest test concentration of 100 mg/L was between 105 and 107 % of the nominal value at the start of the test and between 99 and 106 % at the end of the test. Thus the results were based on nominal concentrations.

Details on test conditions:

The test flasks were incubated in a temperature-controlled water bath at a temperature of 21 °C and illuminated by fluorescent tubes (Philips TLD 36W/840), installed above the test flasks. The test flasks were positioned randomly and repositioned daily. The mean measured light intensity at the level of the test solutions was approximately 6500 Lux (range: 5920 to 6980 Lux, measured at nine places in the experimental area). The light intensity over the incubation area deviated by less than ±15 % from the average light intensity as recommended by the guideline.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

The test item had no statistically significant inhibitory effect on the growth of the algae (average growth rate and yield) during the test period of 72 hours up to and including the highest nominal test concentration of 100 mg/L.
The measured concentration of the test item in the test medium of the highest test concentration of 100 mg/L was between 105 and 107% of the nominal value at the start of the test and between 99 and 106 % at the end of the test (see analytical results and Table 2 in Appendix I). Thus, the correct dosage of the test item could be verified and the test item proved to be stable in the test medium over the test period of 72 hours. Therefore, the biological results were related to the nominal concentrations of the test item.

Results with reference substance (positive control):

The result of the latest positive control test performed in April 2011 showed that the sensitivity of the test system was within the internal historical range (72-hour EC50 for the growth rate: 1.3 mg/L (Harlan Laboratories Study D25712), range of the 72-hour EC50 for the growth rate from 2000 to 2011: 0.71-1.7 mg/L).

Reported statistics and error estimates:

no data

Validity criteria fulfilled:

yes

Conclusions:

The test results of 1,2-Octanediol (CAS 111-86-8), the 72-hour NOEC and the EC50 were at least or higher than 100 mg/L based on the growth rate.

Executive summary:

The influence of the test item 1,2 -Octanediol on the growth of the freshwater green algal species Pseudokirchneriella subcapitata was investigated in a 72-hour static test according to the OECD Guideline 201 (2006), C.3 (1992) and the Commission Regulation (EC) No. 761/2009, C.3. The test item had no statistically significant inhibitory effect on the growth of the algae (average growth rate and yield) during the test period of 72 hours up to and including the highest nominal test concentration of 100 mg/L. The test concentration of 100 mg/L was, therefore, determined to be the 72-hour NOEC. This value might even be higher, but test item concentrations exceeding 100 mg/L were not tested, in accordance with the test guidelines. The 72-hour LOEC and the EC50 were higher than 100 mg/L. In conclusion, the test item had no acute toxic effects on Pseudokirchneriella subcapitata up to and including the test concentration of 100 mg/L.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH

Substances whose physicochemical, toxicological and ecotoxicological properties are likely to be similar as a result of structural similarity may be considered as analogue substances. In this case, experimental data of one substance may provide indications for specific physico-chemical properties and the (eco-) toxicological profile of another, based on a read-across approach (ECHA (2012); ECHA (2013), ECHA (2017a)).

In the present situation an “analogue approach” has been chosen because the target and the source substance are structurally similar substances. The target substance is a mono-constituent substance consisting of a linear C7 chain and two hydroxyl groups. The source substance octane-1,2-diol consists of a linear C8 chain with two hydroxyl groups at the same positions. The molecules only differ by one methylene group in the terminal C chain.

Hence, target and source substances share same chemical structures and functional groups. For the REACH information requirement under consideration, the effects obtained in a study conducted with the source substances are used to predict the effects that would be observed in a study with the target substance if it were to be conducted (ECHA 2017b).

This read-across is based on the hypothesis that source and target substances have the same type of toxicological effects based on common underlying mechanisms. This prediction is supported by physicochemical and (eco-)toxicological data on the substances.

Therefore, the effects of the target substance are predicted to be similar to the effects of the source substance. The exposure to target and source substances causes the same type of effects through a common mechanism.


References:

ECHA (2012) Practical guide 6: How to report read-across and categories. ECHA-10-B-11.1-EN, December 2012.

ECHA (2013) Grouping of substances and read-across approach, part 1: Introductory note. ECHA-13-R-02-EN, April 2013.

ECHA (2017a) Read-Across Assessment Framework (RAAF), Reference: ECHA-17-R-01-EN, Date: March 2017.

ECHA (2017b) Read-Across Assessment Framework (RAAF), Appendix B: Scenario 2.

2. SOURCE AND TARGET CHEMICAL
1) Target chemical
- IUPAC name: 1,2-Heptanediol
- CAS no.: 3710-31-4
- EC no.: 855-780-2
- Molecular formula: C7H16O2
- SMILES notation: CCCCCC(CO)O
- Purity: >= 99 < 100 % (w/w), typical concentration ca 99.8 % (w/w)

2) Source chemical
- IUPAC name: octane-1,2-diol
- CAS no.: 1117-86-8
- EC no.: 214-254-7
- Molecular formula: C8H18O2
- SMILES notation: CCCCCCC(O)CO
- Purity: 99.7% (w/w)

3. ANALOGUE APPROACH JUSTIFICATION
Read-across from (eco-)toxicity studies on the source substances is considered as an appropriate adaptation to the standard information requirements of Annex VII of the REACH Regulation for the target substance, in accordance with the provisions of Annex XI, 1.5 of Regulation (EC) No 1907/2006 (REACH).

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Description of key information

In an Algae Growth Inhibition Test according to OECD TG 201 with Pseudokirchneriella subcapitata, the 72-hour EC50 and EC10 for the read across source substance octane-1,2-diole (CAS 1117-86-8) was higher than 100 mg/L (nominal) based on the growth rate. By applying a read across approach the 72-hour EC50 and EC10 (growth rate) of the target substance heptane-1,2-diol is considered to be > 100 mg/L.

Additional information

No experimental data with the registration substance are available. Therefore read-across to the structural analogue octane-1,2-diol (CAS 1117-86-8) was conducted.

 

Key information

The algae test with octane-1,2-diol was performed with the freshwater green algal species Pseudokirchneriella subcapitata according to the OECD Guideline 201 (2006), and the Commission Regulation (EC) No 761/2009, C.3 in a 72 -hour static test under GLP conditions. The nominal concentrations of the test item of 1, 3.2, 10, 32 and 100 mg/L were tested in parallel with a control. The test item had no statistically significant inhibitory effect on the growth of the algae (average growth rate and yield) during the test period of 72 hours up to and including the highest nominal test concentration of 100 mg/L. The biological results were based on nominal concentrations as the test item was found to be stable during the test duration. The results of the study are: ErC50(72h) > 100 mg/L; EyC50(72h )> 100 mg/L; NOEC (growth rate & yield; 72h) >= 100 mg/L.

 

Conclusion

Based on the test results for the read across source substance octane-1,2-diol (CAS 1117-86-8) it can be assumed that the target substance heptane-1,2-diol will show no statistically significant inhibitory effect on the growth of the algae during a 72h test period up to and including a nominal test concentration of 100 mg/L. Thus, an ErC50(72h) > 100 mg/L and a NOEC(growth rate) of >= 100 mg/L is used for hepatne-1,2-diol. The provided information is regarded reliable and sufficient to cover the data requirements according to REACH Annex VII.