2,6-dimethyloct-7-en-2-yl acetate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

May 10, 2016 to October 14, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Principles of method if other than guideline:

There were no Amendments or Deviations to the Study Plan.

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

As the test item is a volatile substance, the test was conducted using glass tubes completely filled with test medium and tightened/sealed with glass stoppers to avoid losses of test item (closed system). For preparation of the test media, the test item was added into test water in a requisite amount to obtain a solution with a loading rate of 100 mg/L.
Thereafter slow stirring was applied for 96 hours in a closed vessel to reach a maximum concentration of dissolved test item in the test water.After stirring, the lower aqueous and equilibrated phase of the stock solution was carefully separated from the non-dissolved upper test item phase and diluted with test water to obtain the following test media: the dilutions 1:320, 1:100, 1:32, 1:10 and 1:3.2. Additionally, a control (test water without test item) was tested in parallel.

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 (originally from the Daphnia Collection of the University of Basel/Switzerland in 2015) is successfully bred in IES Ltd Laboratories under temperature and light conditions identical to those of the tests.
During breeding, daphnids were generally fed three times a week with an algal suspension of the green algae Desmodesmus subspicatus CHODAT, Strain No. 86.81 SAG. At the start of the test, the organisms used in the test were 6-24 hours old and were not first brood progeny.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

2.5 [mmol/L]
250 as CaCO3 [mg/L]

Test temperature:

The water temperature was 21 °C.

pH:

the pH values of the test media were between 7.7 and 8.0

Nominal and measured concentrations:

At the start of the two test medium renewal periods, the analytically measured test item concentrations in the dilutions 1:32, 1:10 and 1:3.2 were 0.40, 1.8, 4.9 mg/L and 0.50, 1.6 and 5.2, respectively. At the end of the test medium renewal periods, 73 to 114% of the initially measured values were found. The mean measured concentrations over the test duration were calculated to be 0.46, 1.5 and 4.7 mg/L, respectively.

The measured concentrations for the lower treatment dilutions, 1:320 and 1:100, were not analyzed since they were below the NOEC determined in this test.

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1.3 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

The biological results were based on the mean measured concentrations. These were calculated as follows: For each test medium renewal period (i.e. Day0-Day1, Day1-Day2), the mean concentration was calculated as the geometric mean of the test item concentrations measured at the start and the end of the test medium renewal period. From the two geometric mean values obtained, the mean measured test item concentration during the full test period was calculated as arithmetic mean:

Treatment/ Dilution*	Mean measured concentration of the test item [mg/L]
1:320	n.a.
1:100	n.a.
1:32	0.46
1:10	1.5
1:3.2	4.7

*: Dilutions of the aqueous phase of the stock solution with a loading rate of 100 mg/L

n.a.: Not analyzed since below the NOEC determined in this test

Validity criteria fulfilled:

yes

Conclusions:

The 48-hour EC50 was determined to be 1.3 (95% confidence interval : 1.04 – 1.5) based on mean measured concentrations according to this test.

Executive summary:

The acute toxicity of the test item Dihydro Myrcenyl Acetate to Daphnia magna was determined in a 48-hour semi-static test according to the OECD Guideline for Testing of Chemicals, No. 202 (2004) and the Commission Regulation (EC) No. 440/2008, Part C.2. As the test item is a volatile substance, the test was conducted using glass tubes completely filled with test medium and tightened/sealed with glass stoppers to avoid losses of test item (closed system). A semi-static test with daily medium renewal was performed to keep the concentrations of the test item in the test media as constant as possible during the test period of 48 hours. For preparation of the test media, the test item was added into test water in a requisite amount to obtain a solution with a loading rate of 100 mg/L. Thereafter slow stirring was applied for 96 hours in a closed vessel to reach a maximum concentration of dissolved test item in the test water. After stirring, the lower aqueous and equilibrated phase of the stock solution was carefully separated from the non-dissolved upper test item phase and diluted with test water to obtain the following test media: the dilutions 1:320, 1:100, 1:32, 1:10 and 1:3.2. Additionally, a control (test water without test item) was tested in parallel. The preparation of the test media was based on the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures, 2000. At the start of the two test medium renewal periods, the analytically measured test item concentrations in the dilutions 1:32, 1:10 and 1:3.2 were 0.40, 1.8, 4.9 mg/L and 0.50, 1.6 and 5.2, respectively. At the end of the test medium renewal periods, 73 to 114% of the initially measured values were found.

The 48-hour EC50 was determined to be 1.3 (95% confidence interval : 1.04 – 1.5) based on mean measured concentrations according to this test.

Description of key information

The acute toxicity of the test item Dihydro Myrcenyl Acetate to Daphnia magna was determined in a 48-hour semi-static test according to the OECD Guideline for Testing of Chemicals, No. 202 (2004) and the Commission Regulation (EC) No. 440/2008, Part C.2 (Givaudan, 2016). As the test item is a volatile substance, the test was conducted using glass tubes completely filled with test medium and tightened/sealed with glass stoppers to avoid losses of test item (closed system). A semi-static test with daily medium renewal was performed to keep the concentrations of the test item in the test media as constant as possible during the test period of 48 hours. For preparation of the test media, the test item was added into test water in a requisite amount to obtain a solution with a loading rate of 100 mg/L. Thereafter slow stirring was applied for 96 hours in a closed vessel to reach a maximum concentration of dissolved test item in the test water. After stirring, the lower aqueous and equilibrated phase of the stock solution was carefully separated from the non-dissolved upper test item phase and diluted with test water to obtain the following test media: the dilutions 1:320, 1:100, 1:32, 1:10 and 1:3.2. Additionally, a control (test water without test item) was tested in parallel. The preparation of the test media was based on the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures, 2000. At the start of the two test medium renewal periods, the analytically measured test item concentrations in the dilutions 1:32, 1:10 and 1:3.2 were 0.40, 1.8, 4.9 mg/L and 0.50, 1.6 and 5.2, respectively. At the end of the test medium renewal periods, 73 to 114% of the initially measured values were found.

The 48-hour EC50 was determined to be 1.3 mg/L (95% confidence interval : 1.04 – 1.5) based on mean measured concentrations according to this test.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.3 mg/L