3,7-dimethyloct-1-en-3-ol

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

02.10.2014 - 20.03.2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3,7-dimethyloct-1-en-3-ol

EC Number:

242-358-2

EC Name:

3,7-dimethyloct-1-en-3-ol

Cas Number:

18479-49-7

Molecular formula:

C10H20O

IUPAC Name:

3,7-dimethyloct-1-en-3-ol

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

For the determination of the actual test item concentrations, duplicate samples were taken from each treatment at the start and at the end of the test (after 48 hours).
For the 48-hour stability samples, the contents of the respective replicates were combined prior to sampling.
All samples were stored deep-frozen (at about -20 °C) immediately after sampling. Based on pre-experiments for investigation of the storage stability, the test item was found to be stable in the test water under these storage conditions.

Test solutions

Vehicle:

no

Details on test solutions:

Test Water

Reconstituted test water according to ISO 6341 [ISO, 1996] was used in the study. It consisted of analytical grade salts dissolved in purified water at the following nominal concentrations:
Ingredients / Concentration
Properties [mmol/L] [mg/L]

CaCl2 × 2H2O 2.0 294
MgSO4 × 7H2O 0.5 123
NaHCO3 0.75 65
KCl 0.075 5.8
Water Hardness 2.5 250 as CaCO3
Alkalinity 0.8 ---

The ratio of Ca:Mg and Na:K was 4:1 and 10:1, respectively, based on molarities.
The test water was aerated prior to the start of the study until oxygen saturation was reached. During the test period, the test water was not aerated.

The following nominal concentrations of 3,7-dimethyloct-1-en-3-ol were tested: 1.0, 3.2, 10, 32 and 100 mg/L. Additionally, a control (test water without test item) was tested in parallel.

Dosage

The test medium of the highest nominal concentration of 100 mg/L was prepared in a completely filled and tightly closed stirring vessel by completely dissolving 109.3 mg of test item in 1090 mL of test water using intense stirring for 3 hours at room temperature in the dark. Adequate volumes of this test medium were serially diluted with test water to prepare the lower concentrated test media. The test media were prepared just before the introduction of the daphnids (i.e., start of the test).
The preparation of the test media was based on the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures (2000).

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

The study was performed with young daphnids of the species Daphnia magna Straus. A clone of this species (defined by the supplier as clone 5) was originally supplied by the University of Sheffield / UK in 1992. Since that time, the clone has been bred at Harlan Laboratories in reconstituted water of the quality identical to the water quality used in the tests (with respect to pH, main ions, and total hardness) and under temperature and light conditions identical to those of the test.
During breeding, daphnids are generally fed three times a week with an algal suspension of the green algae Desmodesmus subspicatus Chodat, Strain No. 86.81 SAG, supplied by the Collection of Algal Cultures (SAG, Institute for Plant Physiology, University of Göttingen, 37073 Göttingen / Germany) and cultivated at Harlan Laboratories under standardized conditions or a mixture of this algal suspension and a commercial fish diet (Tetra Min® Hauptfutter, supplied by TETRA-Werke, 49304 Melle / Germany).
At the start of the test, the organisms used in the test were 6-24 hours old and were not first brood progeny.

Study design

Test type:

static

Water media type:

other: Reconstituted test water according to ISO 6341

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

250 mg/L as CaCO3

Test temperature:

21-22 °C

pH:

7.8

Dissolved oxygen:

8.4-9.0 mg/L

Nominal and measured concentrations:

Nominal concentrations: 0, 1.0, 3.2, 10, 32 and 100 mg/L
Measured concentrations (day 0): 0, 0.965, 3.08, 9.39, 33.0 and 95.8 mg/L
Measured concentrations (day 2): 0, 0.931, 2.99, 9.63, 32.5 and 93.8 mg/L

Details on test conditions:

Experimental Conditions

The test was performed in a temperature-controlled room. The water temperature was maintained at 21-22 °C.
A 16-hour light to 8-hour dark cycle with a 30-minute transition period was used. Light intensity during the light period was approximately between 800 and 1060 Lux.
The daphnids were not fed during the test.

Study Design

In the definitive test, the enlarged spacing factor of 3.2 between the test concentrations was chosen based on the results of the range-finding test that documented a rather flat concentration-effect relationship; therefore, a large concentration range had to be tested.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

39 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

The measured concentrations of 3,7-dimethyloct-1-en-3-ol in the test media of all test concentrations were between 94 and 103% of the nominal values at the start of the test and between 93 and 102% at the end of the test. Thus, the correct dosage of the test item 3,7-dimethyloct-1-en-3-ol was confirmed. The test item was stable in the test media over the test period of 48 hours. The biological results were related to the nominal concentrations of the test item.

Results with reference substance (positive control):

For evaluation of the quality of the daphnia clone and the experimental conditions, potassium dichromate is tested as a positive control twice a year. The result of the latest positive control test in August 2014 (48-hour EC50: 1.0 mg/L) showed that the sensitivity of the test organisms was within the internal historical range (48-hour EC50 from
2000 to 2014: 0.36-1.1 mg/L).

Reported statistics and error estimates:

Using bionomial distribution, the 95% confidence limits for the 48h-EC50 were calculated as 10 and 100 mg/L.

Any other information on results incl. tables

The biological test results were as follows based on nominal concentrations:

Parameter (0-48 h)	Immobility
	Nominal test item concentration  [mg/L]
24-hour EC50	51
95% confidence interval	32 and 100
24-hour EC0	3.2
24-hour EC100	100
48-hour EC50	39
95% confidence interval	10 and 100
48-hour EC0and
48-hour NOEC	1.0
48-hour EC100	100

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The test item 3,7-dimethyloct-1-en-3-ol had acute toxic effects on Daphnia magna. The 48-hour EC50 was determined to be 39 mg/L with 95%-confidence limits of 10 and 100 mg/L.

Executive summary:

The acute toxicity of the test item 3,7-dimethyloct-1-en-3-ol to Daphnia magna was determined in a 48-hour static test according to the Commission Regulation (EC) No. 440/2008, Part C.2 and the OECD Guideline for Testing of Chemicals, No. 202 (2004).

The nominal test item concentrations tested were 1.0, 3.2, 10, 32 and 100 mg/L. Additionally, a control group was tested in parallel.

As the test item is a volatile substance, the test was performed using glass tubes completely filled with test medium, minimizing the headspace, and tightly sealed with glass stoppers to avoid losses of test item. The preparation of the test media was based on the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures, 2000.

The measured concentrations of 3,7-dimethyloct-1-en-3-ol in the test media of all test concentrations were between 94 and 103% of the nominal values at the start of the test and between 93 and 102% at the end of the test. The biological results were related to the nominal concentrations of the test item 3,7-dimethyloct-1-en-3-ol, since the correct dosage was confirmed.

The biological test results were as follows:

Parameter (0-48 h)	Immobility
	Nominal test item concentration  [mg/L]
24-hour EC50	51
95% confidence interval	32 and 100
24-hour EC0	3.2
24-hour EC100	100
48-hour EC50	39
95% confidence interval	10 and 100
48-hour EC0and
48-hour NOEC	1.0
48-hour EC100	100