1-Hepten-4-yn-3-ol, 6,6-dimethyl-

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

6,6-dimethylhept-1-en-4-yn-3-ol

EC Number:

616-644-6

Cas Number:

78629-20-6

Molecular formula:

C9H14O

IUPAC Name:

6,6-dimethylhept-1-en-4-yn-3-ol

Test material form:

liquid

Details on test material:

Test item: enynolCAS No.: 78629-20-6Batch number: L62042NPhysical state: colourless liquidStorage: store it in a cool, dry, well-ventillated place, free from direct sunlight

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

yes

Details on test solutions:

Preparation of test solutions:
Seven test solutions of different concentration were prepared by mixing appropriate volume of OECD medium and stock solution of the test item. The maximum separation factor between of test vessels was 2.0. Two additional replicates were prepared for controlling the abiotic degradation of the test substance. These test vessels were not inoculated with alga inoculum culture. The following table shows the preparation of test solutions. The volume of the prepared dilution levels was 300 ml except the control solution which was 600 ml.

Preparation of test vessels:
Three replicates were prepared at every test, two at the abiotic control and six at the control level. The vessels contained 75 ml test media.

Test procedure:
The test vessels were closed with silicone stopper and kept in the Binder KBW 400 incubator. For the proper mass transfer of carbon dioxide glass tubes with filter were placed through silicone stoppers. The test was maintained under static conditions for a period of 72 hours. The temperature during the test remained in the 21 ± 2 °C range. The temperature data were harvested by Extech SD200 datalogger. The vessels were shaken and illuminated continuously in the incubator. The vessels were placed randomly into the incubator and were repositioned daily after sampling. One of the vessels of abiotic controls was taken into the incubator with a complete aluminium foil cover to check the stability of test item in the absence of light. This vessel was signed as 8/B (vessel No: 23). The abiotic control on light were signed as 8/A (vessel No: 22).

Test organisms

Test organisms (species):

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

Details on test organisms:

Test species: Pseudokirchneriella subcapitata (Korshikov) F.Hindák (formerly known as Selenastrum capricornutum and Raphidocelis subcapitata)
Source: Culture Collection of Algae and Protozoa, Scottish Marine Institute (www.ccap.ac.uk)
Batch: CCAP 278/4
Date of arriving: 27 October 2017

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

The temperature inside the incubator at the test vessels was measured and registered continuously by Extech SD200 thermometer and datalogger. Throughout the test the temperature was nearly constant.

pH:

At the beginning of the test the pH values were measured in the remaining test solution of the concurrent test vessels at each dilution level.
At the end of the test the pH values were measured in each test vessel. The pH of test solutions was not adjusted at the beginning of the test.

Nominal and measured concentrations:

The nominal concentration of stock solution was 100 mg/L. In the test the following nominal concentrations were applied: 100; 80; 60; 40; 30; 20 and 10 mg/L.
The following concentrations were calculated from the initial and ending values and were applied for the statistical evaluation in the test: 86.86; 69.63; 52.89; 34.94; 25.99 and 17.15 mg/L.
According to the Council Regulation (EC) 440/2008 Enynol is hazardous to the aquatic environment and classified into the third acute toxic hazardous category [GHS Acute aquatic hazard Category Acute III. – 72 h EC50 (for algae or other aquatic plants) > 10 mg/L but ≤ 100 mg/L].

Details on test conditions:

The test organism was grown and hold in OECD medium which was used also for preparing test item solutions. The stock solution was prepared by measuring 150.15 mg of test item into 1 500 ml OECD growth medium. The emulsion was stirred till complete dilution. At the end of the test the concentration of test item was measured from pooled replicates. The samples was filtered with 0.22 μm FilterBio® Hydrophilic PTFE-L Syringe Filter before analytical measurement. The first 5 ml filtrates were disposed. The concentration of the test item was analysed by validated UHPLC method. The validated concentration range is 8 to 41 mg/L. The concentration of test item was measured at the beginning and at the end of the test. The toxic property of test item was investigated at seven concentrations which were prepared by different dilutions of stock solution of test item.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

16.5 mg/L

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

19.45 mg/L

Effect concentrations 3

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

26.62 mg/L

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Remarks on result:

not determinable

Effect concentrations 5

Duration:

72 h

Dose descriptor:

LOEC

Remarks on result:

not determinable

Details on results:

The No Observed Effect Concentration and Lowest Observed Effect Concentration for the test item were calculated by ToxRat® software with Fisher’s exact binominal test with Bonferroni correction for specific growth rate and yield. The results were not conclusive or not determinable.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Acute toxic effect of Enynol was investigated in Freshwater Alga and Cyanobacteria, Growth Inhibition Test (according to OECD 201 guideline).
The ErC50 was 26.62 mg/L at 72 h. According to the Council Regulation (EC) 440/2008 Enynol is hazardous to the aquatic environment and classified into the third acute toxic hazardous category [GHS Acute aquatic hazard Category Acute III. – 72 h EC50 (for algae or other aquatic plants) > 10 mg/L but ≤ 100 mg/L].