1-Hexanol, 2-ethyl-, manuf. of, by-products from, distn. residues

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1-Hexanol, 2-ethyl-, manuf. of, by-products from, distn. residues

EC Number:

271-832-1

EC Name:

1-Hexanol, 2-ethyl-, manuf. of, by-products from, distn. residues

Cas Number:

68609-68-7

Molecular formula:

UVCB, not applicable, see section 1.2 for information on constituents

IUPAC Name:

2,4-diethyl-3-propylpentane-1,5-diol; 2,4-diethyloctan-1-ol; 2-ethylhexan-1-ol; 2-ethylhexane-1,3-diol

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples were taken and analysed after 0 and 72 hours

Test solutions

Vehicle:

no

Details on test solutions:

Due to the low water solubility of the test item, the water-accommodated fraction was perapared by filtration of a saturated solution after stirring for 24 hours. Then, the test solution was disolved with the nutrient medium.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Desmodesmus subspicatus, CHODAT
Source: supplied in February 2008 by the Collection of Algal cultures, Institute of Plant Physiology, Univesity of Göttingen (Göttingen, Germany).

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

No post exposure period

Test conditions

Hardness:

Not indicated

Test temperature:

24 - 29°C

pH:

8.0 - 9.2

Dissolved oxygen:

Not indicated

Salinity:

Not indicated

Nominal and measured concentrations:

Nominal: 10, 18, 32, 56 and 100 mg/L
Measured (geometric mean): 4.42, 7.63, 11.83, 19.39 and 33.80 mg/L throughout the test.
The highest measured concentration is considered as the limit of water solubility of the product.

Details on test conditions:

TEST SYSTEM
- Test vessel: The test was conducted in round cuvettes with a diameter of 10 mm. The vessels were filled with 5 mL of the test solution.
- Initial cells density: 10exp4
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes


OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod and light intensity and quality: The cultures were illuminated constantly with a light intensity of 5800 - 6100 Lux.

EFFECT PARAMETERS MEASURED
- Determination of cell concentrations: Counting chamber.
Every 24 h the cell numbers were determined for each test flask and the photometric absorption of the cuvettes were recorded. At the end of the test, the vessels were microscopically observed to verify a normal and healthy appearance of the algae.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

19 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: not applicable

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

19 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Basis for effect:

biomass

Remarks on result:

other: not applicable

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 34 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: not applicable

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

35 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Basis for effect:

biomass

Remarks on result:

other: not applicable

Details on results:

- Exponential growth in the control (for algal test): yes

Results with reference substance (positive control):

The 72 h-NOEC, the 72h- ErC50 and 72h-EbC50 of the reference substance potassium dichromate was 0.063, 1.2 and 0.31 mg/L.

Reported statistics and error estimates:

The EC50 values and NOEC after 72 hours test duration was calculated with 95% confidence limits when compared with the untreated control group.

Any other information on results incl. tables

1. 72 hour NOEC: 19 mg/L

2. ErC50: > 34 mg/L.

3. EbC50: 35 mg/L.

4. Cell deformations were not observed.

5. The growth inhibition in the treated cultures compared to the control ranged from -7.1 – 5.7 % at nominal concentrations of 10 – 56 mg/L and at nominal 100 mg/L the growth inhabitation was 34.6 %.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

1. 72 hour NOEC: 19 mg/L
2. ErC50: > 34 mg/L.
3. EbC50: 35 mg/L.

Executive summary:

The study examined the effect of Zogol 8 on green alga (Desmodesmus subspicatus) for 72 hours in a growth inhibition test. The cultures were exposed to nominal concentrations of 0, 10, 18, 32, 56 and 100 mg/L of the test substance (corresponding to measured 0, 4.4, 7.6, 11.8, 19.4 and 33.8 mg/L). The study was conducted under static conditions and in accordance with the OECD 201 guideline. The 72 hour NOEC value was determined to be 19 mg/L. The ErC50 and EbC50 was determined to be > 34 and 35 mg/L, respectively. The NOEC, ErC50 and the EbC50 values were based on cell concentration measurements. The growth inhibition in the treated cultures compared to the control ranged from -7.1 – 5.7 % at nominal concentrations of 10 – 56 mg/L and at nominal 100 mg/L the growth inhibition was 34.6 %.