Heptyl undec-10-enoate

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:

01/2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Heptyl undec-10-enoate

EC Number:

268-850-7

EC Name:

Heptyl undec-10-enoate

Cas Number:

68141-27-5

Molecular formula:

C18H34O2

IUPAC Name:

heptyl undec-10-enoate

Test material form:

liquid

Test solutions

Details on test solutions:

The test item was insoluble in water. Hence, the solvent medium CMC (at 30 mg/l) was used. The desired concentrations of the test upto 100 mg/l were prepared prior to the experiment, by dissolving 100 milligram of the test item with the solvent medium CMC (at 30 mg/l). 1.64 gm BG-11 medium in 1 litre demineralized water was dissolved. The pH was adjusted to 8.10 ± 0.10 using 0.1N NaOH solution.

A preliminary test was performed at four concentrations (1 mg/l, 10 mg/l, 50 mg/l & 100 mg/l) of test item.

Since, the range finding study shows significant growth inhibition in algae. The main study was performed at dose concentrations 0.1 mg/l, 0.5 mg/l, 1.0 mg/l, and 10.0 mg/l of the test item involving a comparison of responses in a control group.

Test organisms

Test organisms (species):

Anabaena sp.

Details on test organisms:

The fresh water algal strain “Anabaena sp.” was used for this study. Commercially available media for blue-green algae BG-11 was used at concentration of 1.64 gm in 1 litre demineralized Water.

A culture in test medium was prepared 4 days prior to starting the test. Initial biomass concentration of the strain ‘Anabaena sp.’ was maintained at as low as 104 cells/ml in the medium so as to allow exponential growth. The Biomass (cell count) was measured for ensuring normal growth range.

Seven days before initiation of the study pre-culture of ‘Anabaena sp.’ culture was done. The inoculated flasks were kept in the incubator room with continuous illumination of light intensity and temperature ranging from 2960 – 4440 lux and 21 to 24°C, respectively. After three days, the culture was examined under microscope to check any abnormalities or microbial contamination. During the experiment all the flasks (both control and treated) were kept in the incubator room for 72 hours continuously with above mentioned temperature and illumination

Study design

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

21–24°C controlled at +/- 2 °C

pH:

8.2 ± 1.5

Nominal and measured concentrations:

A preliminary test was performed at four concentrations (1 mg/l, 10 mg/l, 50 mg/l & 100 mg/l) of test item.
Since, the range finding study shows significant growth inhibition in algae. The main study was performed at dose concentrations 0.1 mg/l, 0.5 mg/l, 1.0 mg/l, and 10.0 mg/l of the test item involving a comparison of responses in a control group

Details on test conditions:

Initial Biomass concentration weight : 104 cells per ml or 0.5 mg/l
Illumination : 2960- 4440 lux
Growth medium : BG-11 Medium
Apparatus to determine algal biomass : UV-Vis Spectrophotometer
No. of replicates : Five in control and three in test groups

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

8.9 mg/L

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.8 mg/L

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

3.6 mg/L

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.1 mg/L

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

Preliminary study
No growth inhibitions were recorded in ‘Heptyl Undecylenate’ at the dose concentrations of
1, 10, 50 and 100 mg/l, respectively (Table 1).

Main Study
On the basis of observations from range finding study, main study was conducted at
the concentrations 0.1 mg/l, 0.5 mg/l, 1.0 mg/l, 5.0 mg/l and 10.0 mg/l of ‘Heptyl
Undecylenate’ ’in BG-11 medium. The pH measurement in control and ‘Heptyl
Undecylenate’ concentrations are presented in Table 2. Initial pH of BG-11 medium were in
the range of 8.22 – 8.32 and the final pH were recorded in the range of 6.75-6.78 at the
test termination. The test conditions (Temperature and Light intensity of the experimental
room) during the test period are presented in Table 3. During the test, the temperature was
maintained at the range of 23.6-24.1°C and the light intensity was maintained within the
range of 4252 to 4265 lux.
The algae absorbances (optical density) in control and test item concentrations of
‘Heptyl Undecylenate’ are given in Table 4.
Percent growth inhibition of yield and specific growth rate based on control at 0-72
hours of ‘Anabaena sp.’ exposed to various concentrations of ‘Heptyl Undecylenate’ are
given in Table 5.
The maximum concentration at 0.1 mg/l of test item ‘Heptyl Undecylenate’ did not
elicit any inhibitory effects on the yield and specific growth rate of algal strain ‘Anabaena
sp.’. Therefore the effective concentrations (ECs) and no observed effect concentration
(NOEC) came out as:
EC10 : 1.8 mg/ l
EC20 : 3.6 mg/ l
EC50 : 8.9 mg/ l
NOEC : 0.1 mg/ l
The percentage inhibition and specific growth rate are calculated by comparing with
the solvent control. The percent coefficient of variation (% CV) at different time interval in
the replicate control flasks was calculated as 18.87% which is less than 35%. Hence, the
result of study complies with the requirements of the OECD Guideline.

Applicant's summary and conclusion

Conclusions:

Under the condition of this test, it was concluded that maximum concentration the test item ‘Heptyl Undecylenate’ at 0.1 mg/l elicited no inhibitory effects on the yield and specific growth rate of algal strain ‘Anabaena sp.’. Therefore the effective concentrations (ECs) and no observed effect concentration (NOEC) came out as:
EC10 : 1.8 mg/ l
EC20 : 3.6 mg/ l
EC50 : 8.9 mg/ l
NOEC : 0.1 mg/ l
The study was conducted as per the procedure described in the OECD Guideline for the testing of Chemicals, Freshwater Algae and Cyanobacteria, Growth Inhibition Test Guideline No. 201 Adopted on 28th July 2011.

Executive summary:

The study was conducted to determine the growth inhibition effect of ‘Heptyl Undecylenate’ on algal strain ‘Anabaena sp.’ A range finding study was conducted at four concentrations 1 mg/l, 10 mg/l, 50 mg/l & 100 mg/l of test item. Significant growth inhibitions were found at these concentrations. Therefore, on the basis of range finding study, main study was conducted using concentration of 0.1, 0.5, 1, 5 and 10 mg/l in BG-11 medium. The temperature was maintained within the range of 23.6-24.1°C and light intensity within the range of 4252-4265 Lux throughout the experimentation. Under the condition of this test, it was concluded that ‘Dicapryl Succinate’ elicited no inhibition effects at 0.1 mg/l on the yield and specific growth rate of algal strain ‘Anabaena sp’. Therefore, the Effective concentrations (ECs) and No observed effect concentration (NOEC) came out as:

EC10 : 1.8 mg/ l

EC20 : 3.6 mg/ l

EC50 : 8.9 mg/ l

NOEC : 0.1 mg/ l